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ANALOG AND DIGITAL I/O CARD AD12

1. UNI UNIPOLAR BIPOLAR y BIP SELECT 16 S E ref 8 DIFF _ SWITCH CHO HI i IME o O 12 BIT A D CONVERTER gt tve DC de 15 v CONVERTER 16 SE o5 AJD E MUX OR 2 GAIN 2 DeL MUX 5 sor DATA REGISTER ANAL DMA INPUTS USER DMA TA SELECT S OU or 3 REGISTER CHI5 Loe _ ra 4 DMA MUX INCREMENT amp CONTROL LOGIC CONTROL l Vref IN o B DATA 4 M 12 Bt DIA INTERNAL DATA BUS D A 0 OUT o _ ee o ga Vref IN D A 1 OUT DAT TRIGGER R B o 12 BT DAK REGE ls B LOGIC it FJADDRESS RGE T DECODE S a2 TIMER ENABLE El E REGISTER SELECT Po o a PI apr 1P20o e __ INPUT REGISTER eet cs A hey 0 CONTROL A CIRO GATE A PO REGISTER 16 16 le aut A BIT BIT oro CR CR CR oF OuPUT 9 1 2 INTERRUPT oP2 REGISTER N on yi CONTROL l CRO CIRO Ew clock U at IN FIGURE 1 1 AD12 16 16F BLOCK DIAGRAM 2 5 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted 2 6 ANALOG DIGIT
2. 0 8 7 COUNTER TIMER ENABLE REGISTER 20 cee eee 8 8 TRIGGERING THE A D PERIODICALLY 0 0 00 eee 8 8 GENERATING SQUARE WAVES OF PROGRAMMED FREQUENCY 8 9 MEASURING FREQUENCY AND PERIOD 0 bee es 8 10 GENERATING TIME DELAYS uste spe e Cts pee tae eae is 8 10 Pulse On Terminal Count 2 22 2 cece de na oe da ee ee ee Deg 8 10 Programmable One Shot co 8 11 Software Triggered Strobe 0 0 0 ee 8 11 Hardware Triggered Strobe 000000 c eee 8 11 GENERATING INTERRUPTS WITH THE COUNTER TIMER 8 11 D A CONVERTERS 23053 2208 G248 eed me L a e Ae da IS Fa ee Se Ghee nea ee eed 9 1 PROGRAMMING isos verde bee ERR Ae ee ce e oy eda eee es 9 1 USE WITH AC REFERENCE i cc ees Phd edad Ab ea ee vee Rae ve tag Dae A 9 3 ARBITRARY WAVEFORM OUTPUT 0 0 eee 9 3 CABLING AND CONNECTOR INFORMATION occ 10 1 AD12 16 16F OUTPUT CONNECTOR PIN ASSIGNMENTS 0 00 0 10 1 AD12 16 16F TO AIM 16P CABLE ADAPTER ASSEMBLY occ 10 2 CA37 2 AD12 16 16F ADAPTOR TO SECOND STRING OF AIM 16 s 10 3 SPECIFICATIONS areta ar dal oh oe bala aad Maa Shed dealt glee o 11 1 WARRANTY eit gunk sh Sa oo eae a a AON ne alate dig ek a al et sce ale Se da Sale ee 12 1 EINEARIZATION parno RE Soe wheat dye elle Ae Bae ee od eae ae ea A 1 BASIC INTEGER VARIABLE STORAGE ccoo B 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL DIRECT MEMORY ACCES
3. 6 23 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 20 WRITE VALUE TO A D A CONVERTER Writes a value to a given D A converter NOTES None INPUT params 0 D A channel to write to O or 1 params 1 Write value 0 to 4095 RETURNS DATA None ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver has not ben initialized status 24 D A data out of range not between 0 and 4095 status 25 D A channel not 0 or 1 EXAMPLE int task params 7 status these are globally declared variables task 20 params 0 1 write to D A channel 1 params 1 2047 write half scale to this channel aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver 6 24 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 2 SUMMARY OF ERROR CODES Invalid task number The task number does not fall within the range of 0 through 19 This error code also occurs if any task is selected before a successful initialization with TASK 0 Invalid base address The base I O address does not fall within the range of 100 hex through 3F0 hex A D failed The EOC end of conversion signal did not change state This is usually because the base address has not been set properly Point list is full The point list can only hold 256 entries Invalid point address The point address does not fall within the range of 0 through 255 Invalid gain code The gain co
4. lala Switch 1D las as ar ac as ae Serie REQUIRED Switch setting USING THE SETUP PROGRAM TO SET THE BASE ADDRESS The setup program provided on CD with AD12 16 16F contains an interactive menu driven program to assist you in setting the base address The following procedure demonstrates the use of the setup program 1 Select the desired base address 2 Execute the setup program by typing SETUP and pressing the ENTER key 3 Select the first item in the menu 1 Set board address with the up or down arrow 3 7 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL key and press ENTER 4 Enter the desired base address in hex the program will display a graphic representation of how you should set the switches You may press the space bar to try another address 5 Set DIP switch S4 as shown on the graphic representation INSTALLING THE AD12 16 16F CARD The following procedure will show you how to install the AD12 16 16 inside the computer 1 Ensure that all options have been set as described in the first part of this chapter Be sure to pay close attention to base address selection 2 Turn off the power switch of your computer and remove the power cords from the wall outlet CAUTION FAILURE TO REMOVE POWER FROM THE COMPUTER COULD RESULT IN ELECTRICAL SHOCK OR DAMAGE TO YOUR COMPUTER SYSTEM 3 Remove the computer cover 4 Locate an unused full length slot and remove the blank I O back plate 5 Insert the
5. counter 2 divisor a16drv FP_OFF task FP_OFF params FP_OFF status call the driver Continued 8 8 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL If the 10MHz clock source had been used closer compliance to the desired 8 3KHZ frequency would have been possible i e 10 000 000 8300 1204 8 10 000 000 1205 8 299 KHz Then the counters could have been loaded with division ratios of params 0 5 and params 1 241 5 241 1205 GENERATING SQUARE WAVES OF PROGRAMMED FREQUENCY Either the Counter 1 and 2 combination or Counter 0 can be used to generate square waves of programmable frequency Counter 0 is internally connected to a 100KHZ on board source when the C1 bit of the timer counter enable register is high and the Counter 0 gate input is high Counter 0 can be programmed to operate in a square wave configuration with a maximum divisor of 65 535 Thus the lowest output frequency available directly from Counter 0 is about 1 5HZ The minimum divisor can be as low as 1 yielding a maximum output frequency of 50KHZ Note that the divide by 2 is accomplished by loading a 1 into the counter Calculating the divisor is straightforward For example assume that you want a 1KHZ output frequency The input frequency to the counter is 100KHZ so you must divide by 100 Counter 0 should be set in mode 3 Square wave generator and loaded with 100 as follows outportb BASEADDRESS 10 2 enable 100KHZ
6. 6 _ detect this condition which could cause system lockups or crashes Due to data re formatting that this Task performs it is not a general purpose block move utility If using BASIC it is advisable to make the data array and channel array assign ments just before the CALL statement because declaring a new simple variable after making this assignment will dynamically relocate the arrays and upset operation of this task If you don t need channel data set params 4 O and channel data will be suppressed Once data acquisition has been set up as a background operation using the recycle options of Tasks 5 or 6 a foreground program can be processing the data as soon as acquired using Task 9 to retrieve the data This is excellent for graphic or digital oscilloscope applications As an alternative to Task 9 you may be tempted to retrieve data using BASIC s PEEK function Since PEEK retrieves data a byte at a time if interrupt transfers are active itis possible that an interrupt can occur between reading the low byte and the high byte of a data word thereby changing the halves of a word in mid flight and causing your time sequential PEEK s to return erroneous data Use of Task 9 avoids this problem INPUT params 0 Number of words to transfer params 1 Source memory segment to transfer from params 2 Starting position within source segment 5 14 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL p
7. CABLING AND CONNECTOR INFORMATION AD12 16 16F OUTPUT CONNECTOR PIN ASSIGNMENTS Connections are made to the AD12 16 16F card via a 37 pin D type connector that extends through the back of the computer case The female mating connector can be a Cannon DC 37S for soldered connections or insulation displacement flat cable types such as AMP 745242 1 may be used The wiring may be directly from the signal sources or may be on ribbon cable from screw terminal accessories such as ACCES I O Products Inc part number STA 37 The pin assignments are as follows PIN NAME FUNCTION 5VDC 5VDC Power from the Computer Bus CTRO OUT Counter 0 Output OP3 Digital Output 3 MSB OP1 Digital Output 1 IP3 Digital Input 3 IP1 Digital Input 1 COM Power Common Logic Ground V ref 5V Reference Voltage DACO OUT D A Channel 0 Output DACO REF D A Channel 0 Reference Input CH7 LO CH15 HI Chi 7 Analog Low Input diff l Chl 15 Analog High Input s e CH6 LO CH14 HI Chl 6 Analog Low Input diff l Chl 14 Analog High Input s e CH5 LO CH13 HI ChI 5 Analog Low Input diff l Chl 13 Analog High Input s e CH4 LO CH12 HI Chl 4 Analog Low Input diff l Chl 12 Analog High Input s e CH3 LO CH11 HI ChI 3 Analog Low Input diff l Chl 11 Analog High Input s e CH2 LO CH10 HI Chi 2 Analog Low Input diff l Chl 10 Analog High Input s e CH1 LO CH9 HI Chi 1 Analog Low Input diff l Chl 9 Analog High Input s e CHO LO CH8 HI Chl 0 Analog Low Input
8. QUALITY OF SOLUTION sum of the errors squared 2 797989 The goal is to make the quality as close to O as possible The program checks the resulting polynomial with the data pairs that you entered It computes the f x values for each x value entered using the polynomial subtracts the result from the supplied value of f x and then squares the result The squared results are then summed to compute the QUALITY A 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL If the computed f x values were exact this value would be 0 But since this is an approximation this value will usually be something greater than 0 The QUALITY can be used to indicate how good a particular solution is If the range of points is very wide or if the points make transition from negative to positive values then QUALITY will suffer accordingly For these cases it may be better to use multiple polynomials rather than just one As an example the following data are taken from the NIST tables for type T thermocouples 6 258 5 603 4 468 3 378 1 182 0 2 035 109 200 150 o 4 277 6 702 9 286 12 01 14 86 17 82 20 87 100 150 200 250 300 350 If we take all the data and compute one 5th order polynomial the QUALITY is 473 543732 not very good Now divide the data into two polynomials one on the negative side including O and one on the positive side also using O The results will show a QUALITY of 90 732620 for the negative side and a QUALITY
9. SI DMA Level S2 Unlpolar Blpolar 3 15CH single ended 828CHC ditterentlal gt 4 Basea Address 5 Galn Select Potentiometers RP1 D A 31 Span Adjust RP2 D A 0 Span Adjust RP3 eDfA 0 Zoro Adjust RP4 DfA 1 Zaro Adjuat RP5 Galn 1 Zero Adjust RP Galn 10 Zero Adjust RP7 Galn Span Adjust RP amp Galn 2 Adjust FACTORY SET RP9 Gailn amp Adjust FACTORY SET Jumpers CTROEN Countar 0 Enable CLOCK Clock Selection Input to CTR1 x1 2 Galn of 1 2 When Removed D4 Select IFO as OP4 D Select IF1 as OPS D Select IF as OPS Di Sselect IFS as GOP 3 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL COUNTER TIMER Three 16 bit Counter Timers are provided on AD12 16 16F Refer to the block diagram on page 1 5 for an understanding of the counter timer configuration and to CHAPTER 7 COUNTER TIMER OPERATIONS for a description of applications Counter O is fully accessible to you if multiple AIM 16P s are not being used with the AD12 16 16F as described in the first section FUNCTIONAL DESCRIPTION Counters 1 and 2 are intended for software programmed timed A D start Counter 0 has its clock and output lines available on the I O connector The gate input for Counter 0 is at digital input IP2 CLOCK FREQUENCY SELECT The clock for Counter 1 is either 1 MHz or 10 MHz derived from an on board crystal oscillator and selected by the CLOCK jumper located under DC DC Converter transformer T1 Installing the jumper betw
10. 1 Counter is latched before reading RETURNS DATA params 1 Contains the count read ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 16 read operation number is not 0 or 1 5 17 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL EXAMPLE int task params 7 status these are globally declared variables task 12 params 0 1 latch counter before read a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 13 WRITE DIGITAL OUTPUT BITS Writes a value to digital output bit OPO through OP3 NOTES 1 The value written may be 0 to 15 This represents a four bit binary value with each bit position corresponding to one digital output bit A 1 output sets OPO high and the rest low a 3 output sets OPO and OP1 high and the rest low INPUT params 0 Value to write to digital output bits RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task O status 2 Invalid task number task gt 20 status 13 Digital output value not in range O to 15 EXAMPLE int task params 7 status these are globally declared variables task 13 params 0 15 set all digital output bits high a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 14 READ DIGITAL INPUT BITS Read th
11. A D converter and can sustain a throughput slightly over 100 000 conversions per second 2 The A D will perform conversions on channels according to the scan limits set in either TASK 0 or TASK 1 3 You may not re install the DMA task if the DMA task is still active If you use the recycle mode which generates continuous DMA then TASK 19 which disables DMA must be run before you can successfully run this task again If you are using the non recycle mode then it must have reached the conversion count which automatically disables interrupts and DMA before this task can be run 6 20 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL again The segment registers are not incremented by the handler therefore the maximum data area available is 64K a page for 32 767 conversions Be sure that your data area is not in use by your program or altered by subsequent operations Data may be safely retrieved by TASK 18 during or after TASK 17 operation Upon completion of a DMA operation the tristate DMA request drivers of the AD12 16 16F are placed in the high impedance state This allows more than one AD12 16 16F to use the same DMA level as long as they do so sequentially 6 If you are using the programmable interval timer note that you cannot exit from TASK 17 until the signal at IPO is taken high 4 5 x INPUT params 0 Number of conversions to make params 1 Segment of memory to store data params 2 Trigger s
12. by the scan limits set in Task 1 is performed Task 20 installs an interrupt handler to perform this function Due to the execution delays of the interrupt handler 16 channel block scan rates are limited to about 500 16 channel scans per second on a 4 77 MHz PC If you only scan four channels then 2000 scans per second would be possible Better performance can be expected on Turbo XT s and on AT s During the block scan channels in a 4 77 MHz PC are sampled at about 100 microsecond intervals but other interrupts may produce variable delays in the scan rate If this is a problem you can suppress other interrupts especially the PC timer interrupt while data are collected using Task 20 There are two possible A D trigger sources external trigger inputs and the programmable interval timer If you start missing channels or if the foreground program slows to a crawl you will know that you are operating close to the maximum interrupt rate INPUT params 0 Number of conversions required 1 to 32 767 This is not number of scans params 1 Memory segment to place conversions params 2 Trigger source 0 External trigger input Conversions start on positive transitions of the IPO input and continue until the word count is reached 1 Programmable interval timer In this case IPO should be held low until you want to start conversions After IPO goes high this input will have no further effect params 3 Cycle Recycle operation
13. diff l Chl 8 Analog High Input s e L L GND Low Level Ground Analog Common CTR2 OUT Counter 2 Output CTRO IN Counter 0 Clock Input OP2 Digital Output 2 OPO Digital Output 0 LSB IP2 CTRO GATE Digital Input 2 Also gate for Counter 0 if enabled IPO TRIG O Digital Input 0 Also A D trigger or ctr 1 amp 2 gate if enabled DAC1 REF D A Channel 1 Reference Input CAC1 OUT D A Channel 1 Output L L GND Low Level Ground Analog Common L L GND Low Level Ground Analog Common CH7 HI Chl 7 Analog High Input CH6 HI Chi 6 Analog High Input CH5 HI ChI 5 Analog High Input CH4 HI Chl 4 Analog High Input CH3 HI ChI 3 Analog High Input CH2 HI Chi 2 Analog High Input CH1 HI Chi 1 Analog High Input CHO HI Chl 0 Analog High Input AD12 16 16F TO AIM 16P CABLE ADAPTER ASSEMBLY If you are using an AD12 16 16F with an AIM 16P a special cable adapter may be ordered ONOOARWDND 10 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL directly from ACCES 1 O Products Inc the part number is CA37 1 The cable adapter will allow the use the lower eight channels of the AD12 16 16F for up to eight AIM 16P s This adapter is designed to be used with our standard 37 pin ribbon cable If you desire to construct a cable yourself the following chart provides the recommended pin connections The cable requires two 37 pin D type female connectors Use caution and ensure that in the positions where N C is specified that no connection i
14. status 1 Invalid task number task gt 20 or driver not initialized status 8 Invalid counter not 0 1 or 2 EXAMPLE int task params 7 status these are globally declared variables task 15 params 0 1 counter 1 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 16 HIGH PERFORMANCE BUFFERED CONVERSIONS Fetch multiple conversions from the point list using more efficient code NOTES 1 The point list is used to determine which point addresses to convert 2 This task will use the gain set up in TASK 4 but will not use the function assignments set up in TASK 10 3 This task uses two buffers a data buffer and a point gain buffer Both buffers should be integer buffers of the same length The number of conversions must not exceed the length of the shortest buffer If you do other areas of computer memory may be corrupted cause unpredictable computer behavior The driver has no criteria to evaluate the validity of the pointer It is incumbent upon the application program to supply a valid buffer pointer 4 The point and gain for each analog input is returned in the point gain buffer The point address and gain are packed into one integer with the point address in the upper eight bits and the gain in the lower eight bits 5 The buffers must be declared globally or the driver will not be able to find their segment Using this task a 25MHz 386 computer will achieve thr
15. 0 One cycle After completion of the number of conversions specified interrupts are disabled and operation status is set to zero 1 Re cycle Data are continuously written to the same memory params 0 corresponds to the memory buffer length Operation will continue until stopped by Task 7 Conversions start on each positive transition of the output of counter 2 therefore you must set up counters 1 and 2 using Task 17 RETURNS DATA 5 25 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL The memory segment specified will contain the packed data with the channel number in the lower four bits and the count in the upper 12 bits ERROR CODES status 0 status 1 status 2 status 11 status 19 status 20 status 26 EXAMPLE No error Driver has not been initialized with task 0 Invalid task number task gt 20 Number of conversions zero or negative Trigger type not 0 or 1 Interrupt already active Invalid memory segment int task params 7 status these are globally declared variables task 20 params 0 100 make 100 conversions not scans params 1 0x5000 segment of memory to store conversions params 2 0 params 3 0 external trigger do one cycle only a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver 5 26 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL HDnoaRhWN SUMMARY OF ERROR CODES Driver
16. 0 to 5V output D A Alternatively the D A s may be used with a variable or AC reference voltage as multiplying D A s In both cases the output is the product of the loaded digital count and the reference voltage input The maximum output voltage swing of the D A s is 10V Twelve bit accuracy is maintained at update rates up to 1 KHz PROGRAMMING Since the data is 12 bits wide it has to be written to each D A in two consecutive bytes The first byte contains the four least significant bits of data and the second byte contains the eight most significant bits of data The least significant byte should be written first and is stored in an intermediate register in the D A with no effect on the output When the most significant byte is written it s value is added to the stored least significant data and presented broadside to the D A converter thus assuring a single step update Note that the four bits of the least significant byte are left justified The location of the D A registers is Base Address 4 D A 0 Low Byte Base Address 5 D A 0 High Byte Base Address 6 D A 1 Low Byte Base Address 7 D A 1 High Byte The data format is Least significant byte ls es bs s so om pao x DAO DA3 Least significant four bits of the output value X Don t care bits It is good programming practice to set these to 0 9 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Most significant byte lar
17. 18 or 20 NOTES None INPUT None RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 EXAMPLE int task params 7 status these are globally declared variables task 7 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 8 FETCH DMA INTERRUPT OPERATION STATUS Fetches the status of background tasks 5 6 18 20 NOTES None INPUT None RETURNS DATA params 0 Operation type 0 None 1 DMA Task 6 2 Interrupt Task 5 3 Interrupt Task 18 4 Interrupt Task 20 params 1 Status of operation 0 Done 1 Active in progress params 2 Number of conversions completed so far 5 13 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 EXAMPLE int task params 7 status these are globally declared variables task 8 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver if params 0 0 puts background task complete TASK 9 TRANSFER DATA FROM MEMORY TO ARRAY Takes data from a memory segment and extracts the channel and data and places each into its own array NOTES 1 Do not transfer more words than an array will hold The driver has no way to 2 3 4 5
18. 4 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL REGISTER DEFINITIONS A D REGISTERS A D data are in true binary form and are latched in the A D registers at the end of each conversion These are read at base address and base address 1 in low byte high byte sequence The data are available until the end of the next A D conversion Channel address also in binary form is supplied with the data Base 0 Read Contains the lower four bits of the A D converter output in binary form and the channel address in binary form ADO AD3 The lower four bits of the A D conversion ADO is the least significant bit MAO MA3 The binary representation of the channel number converted MAO is the least significant bit Base 0 Write A write to this location starts an A D conversion The data written is irrelevant This causes the EOC bit of the status register to go high until the conversion is complete Base 1 Read Contains the upper eight bits of the A D converter output in binary form aia AD4 AD11 The most significant eight bits of the A D conversion AD11 is the most significant bit Base 2 Read and Write This register controls the multiplexer scan limits and contains the channel scan starting and ending channel numbers in binary form About 1 2 microsecond after the A D starts a conversion while the sample and hold amplifier is holding the previous channel the multiplexer address is incremented to prepare for the next conve
19. 6 16 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL NOTES 1 If the AIM 16P is used then the digital output bits are not available as they are used by the driver to set channel and gain on the AIM 16P 2 If the AIM 16P is not used the digital input bits may be converted to output bits by installing jumpers D4 through D7 on the AD12 16 16F 3 Output values are not checked for proper range INPUT params 0 Value to output OUTPUT DATA None ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized EXAMPLE int task params 7 status these are globally declared variables task 12 params 0 15 set standard 4 output bits high aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 13 DIGITAL INPUT Reads the digital input bits NOTES 1 If the AIM 16P is used then the digital input bits are not available as they are used by the driver to set channel and gain on the AIM 16P The exception is the IPO bit 2 If the AIM 16P is not used the digital input bits may be converted to output bits by installing jumpers D4 through D7 on the AD12 16 16F INPUT None OUTPUT DATA params 1 Digital input value ERROR CODES status 0 No error 6 17 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL status 1 Invalid task number task gt 20 or driver not initialized EXAMPLE int task params 7 status the
20. 7 status these are globally declared variables task 1 params 0 2 lower scan limit is channel 2 params 1 15 upper scan limit is channel 15 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 2 FETCH GAIN CODE FOR A POINT ADDRESS Returns a previously assigned gain code for a given point address NOTES None INPUT params 0 Point address OUTPUT DATA params 1 Gain code for the given point address ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 5 Invalid point address or index EXAMPLE int task params 7 status these are globally declared variables task 2 params 0 14 fetch gain code for point address 14 6 5 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 3 FETCH POINT ADDRESS FOR A POINT LIST INDEX Returns a previously assigned point address for a given point list index NOTES None INPUT params 0 Point list index OUTPUT DATA params 1 Point address for the given point list index ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 5 Invalid point address or index EXAMPLE int task params 7 status these are globally declared variables task 3 params 0 6 fetch point add
21. AD12 16 16F USER MANUAL ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 11 Number of conversions is O or negative status 19 Trigger mode is not 0 or 1 EXAMPLE int task params 7 status datbuf 100 these are globally declared variables task 4 params 0 100 number of conversions params 1 FP_OFF datbuf passes offset to driver params 2 1 use timers for conversion pulses a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 5 DO N A D CONVERSIONS USING INTERRUPT Perform N conversions and store the results in a specified segment of memory using interrupts This is a background task NOTES 1 The A D will perform conversions on channels according to the scan limits set in either Task O or Task 1 2 You may not re install the interrupt handler if the interrupt is still active Error 20 will result If you use the recycle mode which generates continuous interrupts then Task 7 which disables interrupts must be run before you can successfully run Task 5 again If you are using the non recycle mode then Task 5 must have reached the word count which automatically disables interrupts or disable the operation with Task 7 before Task 5 can be run again 3 The segment registers are not incremented by the handler therefore the maximum data area available is 64K
22. CHAPTER SEVEN COUNTER TIMER OPERATIONS section of this manual However for a full description of features of this extremely versatile IC refer to the Intel 8254 data sheet The counter read write registers are located as follows Base 13 Write Read Counter 1 read or write See description for Base 12 Base 14 Write Read Counter 2 read or write See description for Base 12 Base 15 Write The counters are programmed by writing a control byte into a counter control register at Base Address 15 The control byte specifies the counter to be programmed the counter mode the type of read write operation and the modulus The control byte format is as follows sz se es es os m m wo 4 7 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL sc pwo m m mo aco _ SC0 SC1 These bits select the counter that the control type is destined for scr sco Function Program Counter 0 Program Counter 1 Program Counter 2 Read Write Cmd 200 200 NOTE See CHAPTER SEVEN COUNTER TIMER OPERATIONS for more information RWO RW1 These bits select the read write mode of the selected counter RW1 RWO Counter Read Write Function Counter Latch Command Read Write LS Byte Read Write MS Byte Read Write LS Byte then MS Byte MO M2 These bits set the operational mode of the selected counter 1 mo 200 200 MODE M2 M 0 0 0 0 1 0 0 1 2 X 1 0 3 X 1 1 4 1 0 0 5 1 0 1 BCD
23. Differential If the multiplexer is set up for 16 channel single ended inputs this bit will be a 1 If setup for 8 channel differential inputs this bit will be 0 INT Interrupt This is the interrupt signal which is directed to IRQ2 IRQ7 by the Control Register If interrupts are disabled INT will be a O After generation of an interrupt this bit will be 1 and will remain high until reset by a write to this Status register Your interrupt handler routine should include a write to the Status register at some point to re enable interrupts from the AD12 16 16F MA3 MAO Multiplexer Address This is the channel number of the next channel to be converted if the EOC bit is a 0 MAO is the least significant bit The channel address changes shortly after the EOC bit goes high and when EOC is high may be indeterminate Base 8 Write Clear interrupts A write to this location will clear the interrupt status bit and reset interrupts on the card The value written is irrelevant CARD CONTROL REGISTER This read write register provides status information and software control of interrupts interrupt level DMA and the source of start pulses for the A D 4 5 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Base 9 Read Write Read or write the control register fo so fies co co co fe oo Lore love n o x om s so J INTE This bit enables disables AD12 16 16F generated interrupts 1 enabled O disabled L2 LO These bit
24. TASK 0 Driver initialization TASK 1 Set channel scan limit register of AD12 16 16F TASK 2 Fetch gain code for a given point address TASK 3 Fetch point from point list TASK 4 Assign gain code to range of point addresses TASK 5 Assign range of point addresses to point list TASK 6 Perform conversion of the given point address TASK 7 Perform conversion on next point address in the point list TASK 8 Perform multiple conversions from the point list using polling TASK 9 Perform multiple conversions from the point list using interrupts TASK 10 Function assignments TASK 11 Reset operations TASK 12 Write digital output TASK 13 Read digital input TASK 14 Load counter timers TASK 15 Read counter timers TASK 16 Fetch Multiple Points High Performance point list is used but function assignments are not TASK 17 Perform multiple conversions from the scan register using DMA TASK 18 Transfer data from memory segment to array TASK 19 Terminate DMA operations TASK 20 D A operations TASK REFERENCE TASK 0 INITIALIZE This task provides the driver with default information on l O base address and voltage range This task should be called once at the beginning of the program before any other tasks are called If other tasks are called first they will return error code 1 NOTES 1 Default channel scan limits of O to 7 are set if switch S3 is set in 8CH position otherwise the default will be O to 15 2 Disables all
25. TASK 2 FETCH GAIN CODE FORA POINT ADDRESS 00 6 5 TASK 3 FETCH POINT ADDRESS FOR A POINT LIST INDEX 6 6 TASK 4 ASSIGNS GAIN CODE TO RANGE OF POINT ADDRESSES 6 6 TASK 5 ASSIGN POINT ADDRESSES TO THE POINT LIST 6 8 TASK 6 FETCH DATA FROM A POINT ADDRESS 0 0 0 6 8 TASK 7 FETCH SINGLE DATA POINT USING POINT LIST 2 00 6 9 TASK 8 FETCH MULTIPLE BUFFERED CONVERSIONS 6 10 TASK 9 INTERRUPT DRIVEN DATA ACQUISITION 2 2 0 0 02 e eee eee 6 11 TASK 10 THERMOCOUPLE FUNCTION ASSIGNMENT 00 6 13 TASK 11 RESET FUNCTIONS Le eee 6 16 TASK 12 DIGITAL OUTPUT 0 ee ee 6 17 TASK 13 DIGITAL INPUT ci a i manai bantai eee 6 17 TASK 14 COUNTER TIMER SETUP 0 0 0 0 000 000 0200 008 6 18 TASK 15 READ COUNTER TIMER COUNT ooo 6 19 TASK 16 HIGH PERFORMANCE BUFFERED CONVERSIONS 6 19 TASK 17 DO N A D CONVERSIONS USING DMA 0 00004 6 20 TASK 18 TRANSFER DATA FROM MEMORY TO ARRAY 005 6 22 TASK 19 TERMINATE DMA INTERRUPT OPERATION 00 6 23 TASK 20 WRITE VALUE TO A D A CONVERTER 00 000008 6 24 SUMMARY OF ERROR CODES a rearea n ee 6 25 A D CONVERTER APPLICATIONS reae neia i oeei d a E aE kA NEEE A AE E AA EN E O A E Aa 7 1 CONNECTING ANALOG INPUTS serr av spatii nae e aa aa A OAE EA E Y 7 1 A
26. USER MANUAL CA37 2 AD12 16 16F ADAPTOR TO SECOND STRING OF AlM 16 s If you desire to construct a cable yourself the following chart provides the recommended pin connections The cable requires two 37 pin D type female connectors Use caution and ensure that in the positions where N C is specified that no connections are made AIM 16P AIM 16P FUNCTION AD12 16 16F FUNCTION AD12 16 OMANDABRWND 12 volt power unused Gain selection bit 0 unused Gain selection bit 1 Gain selection bit 2 Address selection bit 0 Address selection bit 1 Address selection bit 2 Address selection bit 3 Common logic ground unused unused unused unused unused unused LL GND Analog Common 10 V REF 12 volt power unused unused unused unused unused unused unused 10 V REF return 5 volt power Output channel 7 Output channel 6 Output channel 5 Output channel 4 Output channel 3 Output channel 2 Output channel 1 Output channel 0 Channel 7 analog input Digital input 1 set for output 5 V REF Digital input 2 set for output Digital input 3 set for output Digital output 0 Digital output 1 Digital output 2 Digital output 3 Common Logic ground Channel 6 analog input Channel 5 analog input Channel 4 analog input Channel 3 analog input Channel 2 analog input Channel 1 analog input LL GND Analog Common Channel 0 analog input LL GND Analog Common D A channel 0 output D A channel 0 reference inpu
27. a page for 32 767 conversions Be sure that your data area is not in use by your program or altered by subsequent operations Data may be retrieved by Task 9 during or after Task 5 operation and will not alter the memory On completion of an interrupt operation the selected level of the 8259 interrupt mask register is disabled and the tristate interrupt drivers of the AD12 16 16F are placed in the high impedance state This allows multiple AD12 16 16F s to use the same interrupt level as long as they do so sequentially Note that any old interrupt vectors are not restored by the driver after AD12 16 16F has finished using the interrupt 5 Conversion speeds up to 3000 samples per second using a 4 77 MHz PC can be reliably achieved using Task 5 For higher speeds use Task 6 Task 5 is subject to disruptions from higher priority interrupts notably from the system timer and this is the main limitation on throughput In general Task 6 is a better 4 x 5 9 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL choice than Task 5 at any speed because it uses much less processing time 6 If you are using the programmable interval timer note that you cannot exit from Task 5 until the signal at IPO is taken high INPUT params 0 Number of conversions to make params 1 Segment of memory to place data must be unused params 2 Trigger source 0 External trigger input Conversions start on positive transitions of the IPO input and continue
28. address bus the higher order bits A16 through A19 are provided by a set of sup plemental registers for each DMA level These are known as the DMA page registers and although there are four DMA levels there are only three page registers Level 0 does not have a dedicated page register because it is used internally for memory refresh and does not require a page register because it refreshes all pages regardless of the A16 A19 address bits To economize it shares the same page register as level 1 Page register I O locations are DMA LEVEL PAGE REGISTER 1 0 LOCATION 081 1 83 HEX 2 2 81 HEX The DMA controller contains other registers that also must be initialized before DMA transfer Which registers you will use will depend on the DMA channel that you are using DMA channel specific registers are 03 HEX 06 HEX Channel 3 memory start address 07 HEX Channel 3 number of byte transfers In addition a fifth register the command register is set by the BIOS at boot up and should not be altered Before a DMA operation can be started all those registers must be initialized This is taken care of by TASK 6 of the standard driver Note that in addition to setting up the DMA controller the AD12 16 16F control register must also be loaded to enable the AD12 16 16F hardware There are two types of DMA operation provided for in the A16DRV driver The first is a straight one time data transfer From 1 to 32 767 conversions
29. aie ae DA i A ea alle 2 2 ANALOG OUTPUT pitais Senta la Seed aie Ak Gees tie a aaah a eae a ete A E ahh 2 3 INTERRUPTS AND DMA cio Sd ia eee Bdge ae ek ae E ong ea A ad a eet 2 3 TRANSFERRING DATA INTO THE COMPUTER 0 000 000 000s eee 2 3 REFERENCE VOLTAGE AND POWER REQUIRED 0 000 000 00202 e eee 2 4 INPUT OUTPUT CONNECTIONS 1 5 cascade ct a dei AOE tae ee ea 2 4 UTILITY SOFTWARES Sues eh eth Guy hited etek aod ad jalapa da 2 4 AD12 16 16F BLOCK DIAGRAM nronu a e ana e ee 2 5 HARDWARE CONFIGURATION AND INSTALLATION 0 0 000 000 eee eee eee 3 1 OPTION SELECTION ss sacha ies cutee eaten ea att OR oo ee deed agate Io ee eg 3 1 MULTIPLEXER CONFIGURATION 0 0 00 0000 3 1 UNIPOLAR BIPOLAR RANGE 00 000 ccc ee 3 1 INPUT VOLTAGE RANGE ovio oa ae ee er a ea ee ee ce a 3 1 OPTION SELECTION MAP oia a ee ea ae 3 3 COUNTER TIMER restin entire tes wa Genk a duced wis eggs cas ae Me oa aes Gan ee ES 3 4 CLOCK FREQUENCY SELECT 0 0 0 0 0c ee 3 4 DIGITARIO T TAs ge ak A Bite wise o athe a tale ie a a aide Nia ota ait Ads 3 4 SELECTING A BASE ADDRESS 0 00020 c ee eee 3 4 STANDARD ADDRESS ASSIGNMENTS FOR 286 386 486 COMPUTERS 3 6 SETTING THE BASE ADDRESS 2 ce ee 3 7 BASE ADDRESS EXAMPLE ortsin a aN AE EA R S E E aieri eee 3 7 USING THE SETUP PROGRAM TO SET THE BASE ADDRESS 3 7 INSTALLING THE AD12 16 16F CARD 2 0 00 2 ee 3 8 CAL
30. card in the slot and install the I O back plate screw To ensure that there is minimum susceptibility to EMI and minimum radiation it is important that there be a positive chassis ground Also proper EMI cabling techniques must be used on I O wiring 6 Inspect the installation for proper fit and seating of the card 7 Replace the computer cover 8 Reapply power to the computer 9 Perform the calibration procedure which follows CALIBRATION AND TEST Periodic calibration of AD12 16 16F is recommended to retain full accuracy The calibration interval depends to a large extent on the type of service that the card is subjected to For environments where there are frequent large changes of temperature and or vibration a three month interval is suggested For laboratory or office conditions six months to a year is acceptable A 4 1 2 digit digital multimeter is required as a minimum to perform satisfactory calibration Also a voltage calibrator or a stable noise free DC voltage source that can be used in conjunction with the digital multimeter is required 3 8 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Calibration is performed using the SETUP program supplied with your card This program will lead you through the set up and calibration procedure with prompts and graphic displays that show the settings and adjustment trim pots This calibration program also serves as a useful test of the AD12 16 16F A D and D A functions a
31. channel possible then reset to 0 and scan until the high limit is reached For example if params 0 13 and params 1 2 the sequence would be 13 14 15 0 1 2 13 14 15 0 1 2 13 14 etc If you are using the card in the 8 channel differential mode avoid setting the lower limit greater than the upper limit because the counter will attempt to cycle through channels 8 through 15 If you wish to perform continuous conversions on only one channel set the low and high scan limits equal to each other Control of the multiplexer address is performed by high speed hardware on the AD12 16 16F card and is independent of the processor Approximately two microseconds after the A D has been triggered and the Sample Hold amplifier is holding the previous sample the multiplexer is advanced to the next channel This allows the instrumentation amplifier to settle before the Sample Hold amplifier returns to the Sample state at the end of the 12 microsecond A D conversion 8 microseconds on AD12 16F This pipelining technique optimizes throughput of the system INPUT params 0 Lower scan limit O to 7 if differential or O to 15 if single ended see note 3 params 1 Upper scan limit 0 to 7 if differential or 0 to 15 if single ended see note 3 OUTPUT DATA NONE ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 6 Differential scan limits are ou
32. counter s gate input Counter Loading Programming of a binary count into the counter Mode 0 Pulse on Terminal Count After the counter is loaded the output is set low and will remain low until the counter decrements to zero The output then goes high and remains high until a new count is loaded into the counter A trigger enables the counter to start decrementing This mode is commonly used for event counting with Counter 0 Mode 1 Retriggerable One Shot 8 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL The output goes low on the clock pulse following a trigger to begin the one shot pulse and goes high when the counter reaches zero Additional triggers result in reloading the count and starting the cycle over If a trigger occurs before the counter decrements to zero a new count is loaded Thus this forms a re triggerable one shot In mode 1 a low output pulse is provided with a period equal to the counter count down time Mode 2 Rate Generator This mode provides a divide by N capability where N is the count loaded into the counter When triggered the counter output goes low for one clock period after N counts reloads the initial count and the cycle starts over This mode is periodic the same sequence is repeated indefinitely until the gate input is brought low This mode is used on the AD12 16 16F card in counters 1 and 2 to generate periodic A D start commands This mode also works well as an alternative to mode O for even
33. driver for use with VisualBASIC for Windows is provided Section 3 of this manual contains a detailed description As a further convenience in application the AD12 16 and AD12 16F are also supported by several third party software packages The drivers for these cards are the same ones used for the Keithley MetraByte DAS 16 16F However these drivers do not take advantage of the channel by channel gain programming capability of the AIM 16 s Some available software packages are listed below a STREAM 16 high speed hard disk transfer utility Continuous A D data transfer rates to hard disk in excess of 50 KHz are possible on PC AT and somewhat slower on PC XT depending on the hard disk controller type b LABTECH NOTEBOOK and LT CONTROL menu driven data acquisition analysis and control packages from Laboratory Technologies Corp c ASYST programmable data acquisition and analysis software from Keithley ASYST d ASYSTANT menu driven data acquisition and analysis software from Keithley ASYST e UNKELSCOPE menu driven data acquisition and analysis from Unkel Software Inc Copyright M I T f SNAPSHOT STORAGE SCOPE menu driven data acquisition and analysis package from H E M Data Corp g TTOOLS utilities for the Turbo Pascal programmer from Quinn Curtiss Software h CTOOLS utilities for the C programmer by the Systems Guild 2 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL
34. execution time of the interrupt service routine and the speed of the processor Task 18 can output in excess of 4000 data points per second on a standard 4 77 Mhz 8088 processor After an interrupt is asserted there is a delay in starting to process the interrupt and this delay varies a little depending on the instruction that is being processed at the time or if a higher priority interrupt is being serviced or requesting service In the PC both the internal DOS timer on level O and the keyboard on level 1 have higher priority than any of the expansion bus interrupts levels 2 7 The latency or variation in the delay causes a time jitter in the steps which is more noticeable at higher output frequencies The latency variation which can amount to several tens of microseconds can be reduced by suppressing other interrupts while outputting data from the D A The following example gives an idea of the steps involved in using TASK 18 For example to generate a 60 HZ sine wave with 50 data points per cycle first set up the counter timer to output a frequency of 60 50 3 KHZ to generate interrupts at the desired rate Note that there is a limitation here due to the rate at which interrupts can be processed Frequency Number of steps lt 4000 The lower the frequency the more steps or points that we can put in the waveform Using 9 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL a clock frequency of 10 MHZ you can set a division ratio o
35. high Thus you can hardware gate Task 18 Once interrupts have been initiated by Task 18 they will run as a background operation until the number of output cycles specified have been performed If you wish to terminate Task 18 before then use Task 7 Task 8 can be used to determine the status of a Task 18 operation This provides for stimulus response type testing where the D A outputs a signal and the A D measures the result The output and input can be set either to transfer a series of values from an array as a single shot operation to transfer the whole array for any number of 5 22 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL cycles up to 65 535 or to continuously transfer That latter mode is useful for wave form generation INPUT params 0 D A Channel number 0 or 1 params 1 Number of D A conversions to transfer 1 to 32767 params 2 Number of cycles to make 0 continuous params 3 D A data array offset params 4 A D data array offset 0 is no array RETURNS DATA If an offset was passed in params 4 then the data array whose offset was passed will have the packed A D conversion The lower four bits will contain the channel number and the upper 12 bits will contain the counts ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 15 D A channel number not 0 or 1 status 11 Conversion count not between 1
36. index reaches the top of the list it is automatically set to the beginning of the list If you desire to set the list index to the top of the list at any time you may use TASK 11 The point list is dynamic During program operation if you desire to clear the point list and add a different set of points this is done quite easily using the tasks provided 6 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL The main advantages of a point list are that conversions can be done in any order and the driver takes care of setting the AIM 16P channel and the AD12 16 16F channel as well as gains linearization and scaling OTHER SOFTWARE FEATURES The driver provides the ability to use the programmable gain feature of the AIM 16P You may assign gains to a given point address directly Each point address may have its own gain code associated with it This is useful when differing input ranges are desired using the same AIM 16P The driver also provides the ability to make a function assignment to each individual point address You may assign a thermocouple curve or a scaling range to a point address Look up tables are contained in the driver to convert counts to the proper temperature Reference junction compensation may also be performed The AD12 16 16F combined with the AIM 16P and this driver provide an excellent tool to handle most kinds of data acquisition signals 6 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK SUMMARY
37. its functionality This driver provides tasks that are unique to the AIM 16P because of its thermocouple and programmable gain capability A task reference for this driver is provided in the following chapter The file names of the AIM 16P in DOS only driver and their language uses are as follows AA16DRV BIN A BASIC loadable driver for use with most interpreted BASIC languages AA16DRV OBJ A Pascal and QuickBASIC linkable driver in object form AA16DRVC OBJ A C linkable driver in object form Also to help you in understand how to use the driver with your program sample programs are provided in three languages C Pascal and QuickBASIC The first three samples are provided for both the standard driver and the AIM 16P driver The last two samples are provided for the standard driver only The programs are SAMPLE 1 Demonstrates data acquisition using polling SAMPLE 2 Demonstrates timer driven data acquisition using interrupts SAMPLE 3 Demonstrates timer driven data acquisition using DMA 5 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL SAMPLE 4 Demonstrates D A conversion SAMPLE 5 Demonstrates digital output To access the functions of the driver a call to a single procedure within the driver is used The name of the procedure for the standard driver is A16DRV the name of the procedure for the AD12 16 16F with AIM 16P is call AA16DRV The procedure is called with three variables which are defined as fol
38. mov DS AX call driver as normal aa16drv FP_OFF amp task P_OFF params FP_OFF status 5 28 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL asm pop DS If you are using a version of Microsoft C prior to version 6 0 use the following code _asm _emit Ox1E _asm _emit 0x86 _asm _emit OxCO _asm _emit Ox8E _asm _emit 0xD8 call driver as normal aa16drv FP_OFF amp task P_OFF params FP_OFF status _asm _emit 0x1F These changes work around a peculiarity of Microsoft C enabling our drivers to locate the variables used in the program USING THE DRIVER WITH TURBO PASCAL The following procedure will show you how to use the driver with Turbo Pascal You may refer to any of the Pascal example programs for further illustration Make sure that you use the proper driver name where required depending on which of the two drivers you use A Include the following compiler directive at the beginning of your program L aa16drv B Declare the three variables for the driver globally type param_array array 1 7 of integer var params param_array task status integer C Declare the driver function as external in using a prototype declaration procedure aa16drv task word param word status word external D Make your assignment to these variables as desired for the function you wish to perform See the reference sections for details on each task E Make the call to the driver 5 29 ANALOG DIGITA
39. of a periodic signal The signal should be applied to the gate input of Counter 0 and a known frequency such as the100 KHz crystal controlled oscillator applied to the Counter 0 clock input During the interval when the gate input is low Counter 0 is loaded with a full count of 65 535 When the gate input goes high the counter begins decrementing until the gate input goes back low at the end of the pulse The counter is then read and the change in count is a linear function of the duration of the gate input signal If Counter 0 receives 10 microsecond duration clock pulses 100KHZz the maximum pulse duration that can be measured is 65 535 10 655 milliseconds Longer pulse durations can be measured if Counters 1 and 2 are used as the input clock source for Counter 0 GENERATING TIME DELAYS There are four methods of using Counter 0 to generate programmable time delays Pulse On Terminal Count After loading the counter output goes low Counting is enabled when the gate goes high The counter output will remain low until the count reaches zero at which time the counter output goes high The output will remain high until the counter is reloaded by a programmed command If the gate goes low during countdown counting will be disabled as long as the gate input is low This mode can be used by the AD12 16 16F card to hold off external start pulses to the A D for up to 650 milliseconds Counter 0 is operated in mode 0 with the desired nu
40. the driver will not occur until all conversions are completed To abandon further conversions you may press any key at the keyboard and the system will return to the calling program If you do not want to wait for data to 5 7 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 2 be collected consider Tasks 5 or 6 wherein data are gathered as a background operation and you can collect and process data at the same time The A D will perform conversions on channels according to the scan limits set in either Task O or Task 1 You must dimension a receiving array that has at least as many elements as the number of conversions specified by params 0 No checks are made by the driver on whether you are requiring more conversions than the array will hold If you do other areas of computer memory may be corrupted causing unpredictable computer behavior If using BASIC after assigning the pointer to the receiving array do not introduce any new simple variables before entering the CALL A problem would arise because of the way that BASIC stores array variables They are located in memory above the data area for simple non array variables which in turn is located above the program storage area If you introduce a simple variable that has not been used before BASIC makes room for this variable by re locating all the variables upwards in memory If you assign the pointer using VARPTR to the receiving array before a new variable is introduced and
41. then enter the CALL the actual location of the array will have changed and the CALL routine will write data to the old array location causing unpredictable computer behavior Conversion rates in excess of 2000 conversions per second are attainable using this task Since interrupts in the computer mainly the timer interrupt divert the CPU away from attending to transferring data from the A D for several hundred microseconds data may be lost above 3000 samples per second INPUT params 0 Number of conversions to make params 1 Offset of a data array to store counts read params 2 Trigger source 0 External trigger input Conversions start on positive transitions of the IPO input and continue until the conversion count is reached NOTE Exit from the routine cannot take place until a number of pulses equal to the word count have been applied 1 Programmable interval timer In this case IPO should be held low until you want to start conversions After IPO goes high this input will have no further effect Exit occurs when the word count is released Conversions start on each positive transition of the output of counter 2 therefore you must set up counters 1 and 2 using Task 17 RETURNS DATA The array whose offset was passed in params 1 will contain the conversions The upper 12 bits contain the counts which are from 0 to 4095 regardless of polarity The lower 4 bits contain the channel number 5 8 ANALOG DIGITAL 1 0 CARD
42. to 15 2 Disables all interrupt DMA and external trigger functions 3 Programmable interval timers 1 and 2 are configured for rate generator mode and set to produce a 1 KHz pulse rate 10 KHz with a 10 MHz clock INPUT params 0 Base Address params 1 Interrupt request level IRQ params 2 DMA channel OUTPUT DATA NONE ERROR CODES status 0 No error status 2 Invalid task number task gt 20 status 3 Invalid base address params 0 gt Ox3f0 or lt 0x200 status 4 Invalid interrupt level params 1 lt 2 or gt 7 status 5 Invalid DMA channel params 2 is not equal to 1 or 3 status 22 Card not present or I O base address set improperly EXAMPLE int task params 7 status these are globally declared variables task 0 params 0 0x300 base address 300 hex params 1 5 interrupt IRQ5 params 2 3 DMA level 3 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 1 SET MULTIPLEXER SCAN LIMITS This task sets the multiplexer scan limits for the A D converter NOTES 1 You should set the limits prior to a call to tasks 3 4 5 6 18 20 if the default 5 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 3 5 x _ limits set in task O are acceptable then this task need not be called If the lower limit is greater than the higher limit the multiplexer will scan starting at the lower limit through the highest
43. until the word count is reached 1 Programmable interval timer In this case IPO should be held low until you want to start conversions After IPO goes high this input will have no further effect Conversions start on each positive transition of the output of counter 2 therefore you must set up counters 1 and 2 using Task 17 params 3 Cycle Recycle operation 0 One cycle After completion of the number of conversions specified interrupts are disabled and operation status is set to zero 1 Recycle Data are continuously written to the same memory params 0 corresponds to the memory buffer length Operation will continue until stopped by Task 7 RETURNS DATA Data are stored in the segment address passed starting at offset 0 The data may be converted and placed in an array by using task 9 ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 11 Number of conversions is 0 or negative status 19 Trigger code not 0 or 1 status 20 Interrupt or DMA already active status 26 Invalid memory segment status 27 Recycle code not 0 or 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL EXAMPLE int task params 7 status globally declared variables task 5 params 0 100 number of conversions params 1 0x5000 passes data segment to driver should be unused params 2 1 use timers for conversion pul
44. 004 5 14 TASK 10 SET COUNTER 0 MODE 0 0 0 00 5 16 TASK 11 LOAD COUNTER O c cccccccccc ee 5 17 TASK 12 READ COUNTERO cccccccccc ee 5 17 TASK 13 WRITE DIGITAL OUTPUT BITS occccccccccc 5 18 TASK 14 READ DIGITAL INPUT BITS 0 00 00 00 0 00000 5 19 TASK 15 WRITE VALUE TO A SINGLE D A CONVERTER 5 19 TASK 16 WRITE TO BOTH D A CONVERTERS 2 0 2 cee eee 5 20 TASK 17 SET COUNTER 1 AND 2 RATE cccccccc 5 21 TASK 18 D A OUTPUT ON A D EOC c 0occccccccccc ee 5 22 TASK 20 A D CHANNEL SCAN ON INTERRUPT 0 000 000 0008 5 25 SUMMARY OF ERROR CODES 1 ee 5 27 USING THE DRIVER WITH TURBO OR BORLAND C ooo 5 28 USING THE DRIVER WITH MICROSOFT C 0 0 00 000000000 5 28 USING THE DRIVER WITH TURBO PASCAL 00 00 0000 000000 5 29 USING THE DRIVER WITH QUICKBASIC 0 0 0000 000000000 5 30 AD12 16 16F WITH AIM 16P DRIVER REFERENCE 0 000 000 0 000 000 eee 6 1 USING THE DRIVER 00d tated bat Pah tek he SR a A a Oe Seni Seles 6 1 THE POINT LIST CONCEPT oii dat beste an BE a ee ea we are 6 1 OTHER SOFTWARE FEATURES 0 0 0 00 ee 6 2 TASK SUMMARY vratni yn a a cee a tad ees at ea A aie Ae 6 3 TASK REFERENCE cx iria see eae a eed ee a de ayn ces 6 3 TASK 0 INITIALIZE cscs cis a ek ak ecient a eee hd oe te Eta i ea 6 3 TASK 1 SET MULTIPLEXER SCAN LIMITS o occcccccccccooo 6 4
45. AL 1 0 CARD AD12 16 16F USER MANUAL HARDWARE CONFIGURATION AND INSTALLATION OPTION SELECTION Many of the AD12 16 16F card features are selected by hardware jumpers or switches At least one of each of the option categories must be selected if the card is to operate correctly The setup program provided on CD with the card provides menu driven pictorial presentations to help you quickly set up the card You may also refer to FIGURE 3 1 OPTION SELECTION MAP and the following sections to set up the card The card need not be plugged into the computer at this time MULTIPLEXER CONFIGURATION Select the desired A D input multiplexer configuration using switch S3 located in the upper right hand corner of the card near the I O connector 8 Channel Differential Input 8CH position 16 Channel Single Ended Input 16CH position UNIPOLAR BIPOLAR RANGE In the unipolar mode inputs can be positive only i e ranges from zero volts to some positive voltage The maximum voltage span in the unipolar mode is 10V In the bipolar mode inputs can be between positive and negative full scale limits Select for unipolar or bipolar range using switch S2 located just above U38 Unipolar UNI position up Bipolar BIP position down INPUT VOLTAGE RANGE Input voltage range is selected using sections of GAIN SEL switch S5 for gains of 1 2 5 and 10 and by installing the 0 5 GAIN jumper Note that switch S5 is oriented such that when the card
46. ARD AD12 16 16F USER MANUAL A D CONVERTER APPLICATIONS CONNECTING ANALOG INPUTS The AD12 16 16F offers optional switch selected eight channel differential or 16 channel single ended input configurations Single ended configuration means that you have only one input relative to ground A differential input provides two inputs and the signal corresponds to the voltage difference between these two inputs Although the single ended mode provides ability to accept 16 inputs rather than eight this configuration is suitable only for floating sources i e a signal source that does not have any connection to ground at the source Thus if the signal source has one side connected to a local ground the eight channel differential configuration should be used A differential input responds only to difference signals between the high and low inputs In practice the signal source ground will not be at exactly the same voltage as the computer ground where the AD12 16 16F is because the two grounds are connected through ground returns of the equipment and the building wiring The difference between the ground voltages forms a common mode voltage i e a voltage common to both inputs that a differential input rejects up to a certain limit In the case of the AD12 16 16F the common mode limit is 10V If you have a combination of floating and ground referred signal sources use the differential configuration For the floating signals connect a jumper betw
47. CESS CHANNEL Levels Levels 1 or 3 switch selectable Enable Via DMA bit of Control Register Termination By interrupt on terminal count or auto initialize Transfer Capable of 150 000 transfers per second User is responsible for initialization of the DMA controller in the computer With the DMA bit set double byte requests are generated at the end of each A D conversion Data are latched and available for transfer until the end of the following A D conversion The transfer sequence is low byte high byte 11 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL PROGRAMMABLE TIMER Type 82C54 2 programmable interval timer Counters Three 16 bit down counters two permanently concatenated with 1 10MHz clock as programmable timer One is uncommitted Output Drive 2 2mA at 0 45V 5 LSTTL loads Input Gate TTL DTL CMOS compatible Clock Frequency DC to 10MHz Active Count Edge Negative edge Min Clock Pulse Width 30nS high 50nS low Timer Range 2 5 MHz to lt 1 pulse hr ENVIRONMENTAL Operating Temp 0 to 50 C Storage Temp 20 to 70 C Humidity 0 to 90 RH non condensing Weight 10 oz Power Required 5VDC 900 mA typical 12VDC 250 mA typical 11 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL WARRANTY Prior to shipment ACCES products are thoroughly inspected and tested to applicable specifications
48. ERAL Under this Warranty liability of ACCES is limited to replacing repairing or issuing credit at ACCES discretion for any products which are proved to be defective during the warranty period In no case is ACCES liable for consequential or special damage arising from use or misuse of our product The customer is responsible for all charges caused by modifications or additions to ACCES equipment not approved in writing by ACCES or if in ACCES opinion the equipment has been subjected to abnormal use Abnormal use for purposes of this warranty is defined as any use to which the equipment is exposed other than that use specified or intended as evidenced by purchase or sales representation Other than the above no other warranty expressed or implied shall apply to any and all such equipment furnished or sold by ACCES 12 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted 12 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL APPENDIX A LINEARIZATION A common requirement encountered in data acquisition is to linearize or compensate the output of non linear transducers such as thermocouples flowmeters etc The starting point for any linearizing algorithm is a knowledge of the calibration curve input output behavior of the transducer This may be derived experimentally or may be available in manufacturer s data or standard tables There are several approaches to linearization The two most common are
49. F USER MANUAL The readback command byte format is CNT When is O latches the counters selected by bits CO C2 STA When is 0 returns the status byte of counters selected by CO C2 CO C1 C2 When high select a particular counter for readback CO selects Counter 0 C1 selects Counter 1 and C2 selects Counter 2 You can perform two types of operations with the readback command When CNT 0 the counters selected by CO through C2 are latched simultaneously When STA 0 the counter status byte is read when the counter I O location is accessed The counter status byte provides information about the current output state of the selected counter and its con figuration The status byte returned if STA 0 is fx fio ios fi foo foo fo oo our we rw we we wi mo eo OUT Current state of counter output pin NC Null count This indicates when the last count loaded into the counter register has actually been loaded into the counter itself The exact time of load depends on the configuration selected Until the count is loaded into the counter itself it cannot be read RW1 RWO Read Write command M2 M1 MO Counter mode BCD BCD 0 is binary mode otherwise counter is in BCD mode If both STA and CNT bits in the readback command byte are set low and the RW1 and RWO bits have both been previously set high in the counter control register thus selecting two byte reads then reading a selected counter address location
50. FF params FP_OFF amp status call the driver TASK 18 D A OUTPUT ON A D EOC Uses the EOC interrupt to time the outputs to the D A converter Optionally if an address to an array is passed the values converted by the A D are returned NOTES 1 The A D converter is triggered by the on board interval timer The resulting 3 6 7 gt gt xw Nyo EOC s will provide periodic interrupts delayed eight to twelve microseconds depending on A D conversion time from the timer pulse Channel scan limits and interrupt rate from the timer are set independently preceding this task using Tasks 1 and 17 Speed is dependent on the rate at which interrupts can be processed and varies according to the type of hardware and CPU clock rate Typically with a 4 77 MHz clock interrupt rates approaching 4 KHz are possible Due to the use of interrupts D A update has variable latency delays of several microseconds which can be improved by suppressing other higher priority interrupts such as the computer s timer interrupt on level 0 If using BASIC it is advisable to make the data array assignments just before the CALL statement because declaring a new simple variable after making this assignment will dynamically relocate the arrays and upset operation ofthis task Digital input IPO is polled before enabling interrupts If IPO is held low by external hardware this will hold off the start of D A output until IPO is taken
51. However should equipment failure occur ACCES assures its customers that prompt service and support will be available All equipment originally manufactured by ACCES which is found to be defective will be repaired or replaced subject to the following considerations TERMS AND CONDITIONS If a unit is suspected of failure contact ACCES Customer Service department Be prepared to give the unit model number serial number and a description of the failure symptom s We may suggest some simple tests to confirm the failure We will assign a Return Material Authorization RMA number which must appear on the outer label of the return package All units components should be properly packed for handling and returned with freight prepaid to the ACCES designated Service Center and will be returned to the customer s user s site freight prepaid and invoiced COVERAGE First Three Years Returned unit part will be repaired and or replaced at ACCES option with no charge for labor or parts not excluded by warranty Warranty commences with equipment shipment Following Years Throughout your equipment s lifetime ACCES stands ready to provide on site or in plant service at reasonable rates similar to those of other manufacturers in the industry EQUIPMENT NOT MANUFACTURED BY ACCES Equipment provided but not manufactured by ACCES is warranted and will be repaired according to the terms and conditions of the respective equipment manufacturer s warranty GEN
52. IBRATION AND TEST i ege had oa eed ee a ee te es E E 3 8 PROGRAMMING THE AD12 16 16F 2 ee 4 1 AD12 16 16F REGISTER ADDRESS MAP 0 0 0 0 000 eee 4 1 REGISTER DEFINITIONS cues cea ke ke bee hee ad ee ee ek 4 2 AID REGISTERS sima ea ee a VR a ee AA 4 2 DIGITAL VO p Spenn oe ls ee Reed et ale See ie ee ee a oe a 4 3 ANALOG OUTPUTS culona ara he sla ae eee de i ad A an ae Ai 4 4 CARD STATUS AND CLEAR INTERRUPT 0 0 0 0 00 002 0005 4 5 CARD CONTROL REGISTER 4 5 COUNTER TIMER REGISTERS 0 0 0cccccccc ee 4 6 STANDARD DRIVER REFERENCE ici a as a i wale el Ds 5 1 TASK SUMMARY Si is da Pt beeen cole Ree eet A gaa wate 5 3 TASK REFERENCE solia Aa cant tae dee a Aaa dal ee ia he eR ace a 5 3 TAS K202 INITIALIZE mio ia sh Sig nee wanted a a 5 4 TASK 1 SET MULTIPLEXER SCAN LIMITS 0 00 0 00 0 0000 0 5 5 TASK 2 FETCH MUX SCAN LIMITS AND CURRENT CHANNEL 5 6 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 3 PERFORM A SINGLE A D CONVERSION oc occcccccc 5 7 TASK 4 DO N A D CONVERSIONS USING POLLING 0 0 0 5 7 TASK 5 DO N A D CONVERSIONS USING INTERRUPT 5 9 TASK 6 DO N A D CONVERSIONS USING DMA 0 00 0 nann 5 11 TASK 7 TERMINATE DMA INTERRUPT OPERATION 000 5 13 TASK 8 FETCH DMA INTERRUPT OPERATION STATUS 00 5 13 TASK 9 TRANSFER DATA FROM MEMORY TO ARRAY 0
53. L 1 0 CARD AD12 16 16F USER MANUAL aa16drv ofs task ofs params ofs status F Compile and link the program USING THE DRIVER WITH QUICKBASIC The following procedure will show you how to use the driver with Microsoft QuickBASIC You may refer to any of the QuickBASIC sample programs for further illustration Make sure that you use the proper driver name where required depending on which of the two drivers you use The following procedure will allow you to use the driver both in the QuickBASIC environment and from the command line compiler A Declare the three variables for the driver as global DIM TASK STAT PARAMS 7 B The array dimension statement must be followed by the COMMON statement for the driver to be able to find the array Note Steps A and B are necessary for any array that will be used by the driver Certain tasks within the driver required the address of a data buffer so these two steps would need to be performed for those arrays as well COMMON SHARED PARAM C Now DECLARE the driver routine This declaration must include a BYVAL statement before the array variable DECLARE SUB A16DRV TASK BYVAL PARAM STAT D Make your assignment to these variables as desired for the function you wish to perform See the reference section on each task for details E Make the call to the driver The CALL statement must explicitly pass the offset of the array variable CALL A16DRV TASK VARPTR PARAM 1 STAT F T
54. NALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL COMMENTS ON NOISE INTERFERENCE 0 0 eee 7 1 GrOUNGIEOOPS cia tata lt cate de cot A Sy ee he ade ie teh ahd Deets a dere Bid iat 7 2 External NoiSe 2 2 sa nie oe Ae Nek tack a are hind Bee aed is a oe 7 2 INPUT RANGE AND RESOLUTION SPECIFICATIONS 0 0000 eee eee 7 2 CURRENT MEASUREMENTS coco 7 2 MEASURING LARGE VOLTAGES 1 0 cee ee 7 3 ADDING MORE ANALOG INPUTS 1 eee 7 3 PRECAUTIONS NOISE GROUND LOOPS AND OVERLOADS 0000 7 4 COUNTER TIMER OPERATIONS ooo 8 1 OPERATIONAL MODES 0 020065 2 fb ee bah aah eh ba dam debe dod ed a a aa 8 1 Mode 0 Pulse on Terminal Count 20 cee eee 8 1 Mode 1 Retriggerable One Shot 0 0 2 ee eee 8 2 Mode 2 Rate Generator isi pe sete eee bea ee ne ra ebb eee el bee wees 8 2 Mode 3 Square Wave Generator 0 cee eee 8 2 Mode 4 Software Triggered Strobe 1 cee eee 8 2 Mode 5 Hardware Triggered Strobe 2020 cee ee 8 2 PROGRAMMING iria ek acai ek ae A eee de ene ee eS RE ea oe ee 8 3 READING AND LOADING THE COUNTERS 0 000 cee eee eee 8 4 PROGRAMMING EXAMPLES ccoo 8 6 Generating a Square Wave Output 0 000020 8 6 Determining Status of Counter 1 21 0 ee 8 6 Using Counter 0 as a Pulse Counter 0 00 ee es 8 6 Reading Counter 0 und Pha hed eet he bee RA ae eae 8 6 PROGRAMMING EXAMPLES USING THE A16DRV DRIVER
55. OFF params FP_OFF amp status call the driver params 0 2 check for end of scan process do aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver while params 1 0 wait until end of scan or if you do not want to wait until end of scan params 0 3 stop interrupt process sub task aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 10 THERMOCOUPLE FUNCTION ASSIGNMENT Provides sub tasks to assign thermocouple curves and scaling factors to a given point address A subtask is also provided to use the thermocouple tables to manually linearize a given value NOTES 1 The built in NIST tables are designed to convert A D counts to temperature 6 12 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 2 4 5 x directly When using SUBTASK 1 the driver expects the passed counts to be multiplied by 16 if using the bipolar mode and multiplied by 8 if using a unipolar mode Curves are assigned to a point address by calling SUBTASK 2 with the ASCII code of one of the curves listed in the table that follows Also temperature units are assigned in the same manner If reference junction compensation using the AIM 16P on board sensor is desired then assign this sensor to the point list as the first channel of a given AIM 16P ie 0 16 32 48 etc Make sure that the TMP jumpers are installed on the AIM 16P Final
56. ONVERSION Perform a single A D conversion triggered by software The multiplexer is automatically incremented after the conversion NOTES 1 The A D will perform conversions on channels according to the scan limits set in either Task O or Task 1 Task 3 is the only task that allows A D conversion to be initiated on software command It is slow because it is limited by program execution speed which for interpreted BASIC can takes several milliseconds per line of code A tight loop will perform about 200 conversions per second on a 4 77 MHz PC If compiled BASIC is used about 4000 samples per second can be obtained on a 4 77 MHz computer 2 INPUT None RETURNS DATA params 0 A D data 0 to 4095 if unipolar 2048 to 2047 if bipolar params 1 Channel number 0 to 7 if differential or 0 to 15 if single ended ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 9 No end of conversion a timeout occurred indicating a hardware failure EXAMPLE int task params 7 status these are globally declared variables task 3 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 4 DO N A D CONVERSIONS USING POLLING Perform N conversions and store the results in an array NOTES 1 Since the CPU is performing the A D polling and data transfers as a foreground operation exit from
57. S amp di hie lalla dl ata Se data AA a and ide C 1 IBM PC DMA STRUCTURE 2 0 cee ee C 1 PAGE REGISTER AND DMA CONTROLLER FUNCTIONS 00 0000 C 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 1 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omittted 1 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL FUNCTIONAL DESCRIPTION The AD12 16 and AD12 16F are multifunction high speed analog digital I O cards for use in IBM Personal Computers They are full length cards that can be installed in expansion slots of IBM PC XT AT and compatible computers With this card installed the computer can be used as a precision data acquisition and control system or as a signal analysis instrument The following paragraphs describe functions provided by this card ANALOG INPUTS The card accepts up to eight differential or 16 single ended analog input channels Inputs are protected against overvoltages up to 35 volts and typically survive static discharges beyond 4000 volts When power is off the inputs are open circuited providing fail safe operation and continue to offer 20V overvoltage protection The channel input configuration is switch selectable on the card providing a choice between sixteen single ended channels or eight differential channels In the latter case common mode rejection ratio is a minimum 6 dB and common mode voltage range is 11V Inputs are amplified by an instrumentation am
58. SK 17 Set counter 1 and 2 rate TASK 18 D A wave form output and A D input in A D EOC interrupt TASK 19 Analog trigger function TASK 20 A D block channel scan on Interrupt Speed is medium and operation is in the background TASK REFERENCE The following pages will provide details on the use of each of the driver s tasks The code fragments are written in the C programming language but the code is mostly assignments and the call to the driver so it should not be difficult to translate into your development language Other methods of calling the driver are discussed at the end of this chapter starting on page 28 Another detail that you should remember is how array indices are used in your particular language In C the first element of an array is O as will be seen in the reference In Pascal the first element of an array is whatever you made it in the type declaration for that array In BASIC or QuickBASIC the first element should be a 1 TASK 0 INITIALIZE 5 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This task provides the driver with default information on I O base address interrupt level and DMA channel This task should be called once at the beginning of the program before any other tasks are called If other tasks are called first they will return error code 2 NOTES 1 Default scan limits of 0 to 7 are set by this task if switch S3 is set in 8CH position otherwise the default will be 0
59. Set the selected counter to count in binary BCD 0 or BCD BCD 1 4 8 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL AD12 16 16F STANDARD DRIVER REFERENCE PROGRAMMING USING THE DEVICE DRIVERS Using direct register access to program the AD12 16 16F is straightforward but the coding can be rather tedious To assist you in building your application quickly ACCES provides two device drivers The first driver is used when there is no AIM 16P sub multiplexer board attached This driver is provided in three forms Which form you use will depend on the programming language you wish to develop your application with This section of the manual contains detailed information on the functions available in the standard driver The standard driver should be used when there is no sub multiplexer board attached to the AD12 16 16F The driver provides a wide range of functions that would take weeks of development time to create The chapter is divided into three sections the first is a task summary the second is the task reference and last is an error code summary The driver in DOS only are A16DRV BIN A BASIC loadable driver for use with most interpreted BASIC languages A16DRV OBJ A Pascal and QuickBASIC linkable driver in object form A16DRVC OBJ A C linkable driver in object form The second driver is designed to be used when an AIM 16P sub multiplexer board is attached This driver is significantly different from the first driver in
60. ain Drift 45 PPMC maximum Trigger Source Software selectable external trigger programmable timer or program command SAMPLE AND HOLD AMPLIFIER Acquisition Time 1 microsecond to 0 01 typical for full scale step function input Aperture Uncertainty 0 3 nanosecond typical REFERENCE VOLTAGE OUTPUT Voltage 5 0VDC 0 05VDC Temp Coefficient 30PPM C Load Drive 5mA maximum 11 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL D A SPECIFICATION Channels 2 independent Type 12 bit double buffered multiplying Linearity 1 2bit Monotonicity 1 2bit Output Range 0 to 5VDC when using the 5V reference May also be used with other DC or AC reference input Maximum output limit 10V Output Drive 10 mA minimum Output Resistance lt 0 1 ohm Ref Input Range 10V Gain 1 000 adjustable 1 Settling Time 2 microseconds to 0 01 for full scale step input DIGITAL I O Inputs Logic high 2 0 to 5 0 VDC at 20 uA maximum at 2 7V Logic low 0 5 to 0 8 VDC at 0 4mA maximum Outputs Logic high 2 4V minimum at 0 4mA source Logic low 0 5V maximum at 8 0mA sink INTERRUPT CHANNEL Levels Levels 2 through 7 software selectable Enable Via INTE of Control Register Interrupts are latched in an internal flip flop on the card The state of this flip flop corresponds to the INT bit in the Status Register Service routines should acknowledge and re enable the interrupt flip flop DIRECT MEMORY AC
61. and 32767 status 20 Interrupt already active EXAMPLE int task params 7 status these are globally declared variables int DAout 10 0 0 0 0 0 4095 4095 4095 4095 4095 also global task 18 params 0 1 use D A channel 1 params 1 10 cycle continuously params 3 FP_OFF DAout pass this to driver params 4 0 do not use AD data a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver 5 23 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 19 ANALOG TRIGGER Waits for a given A D input to reach a certain level and then exits NOTES 1 This task is useful for data compression For instance if you are only interested in values above or below a certain level this task may be used to sense this condition Upon return from this task you may start your conversions It is possible to get stuck in the wait loop indefinitely if the trigger conditions are not met You can exit this task by pressing any key Since this task requires use ofthe AD12 16 16F multiplexer scan setting register at Base Address 2 for selection of the trigger channel the previous value of this register is saved and restored upon exit The slope parameter controls the direction of triggering For example if params 1 1024 on the 5V range the trigger level will be 2 5V and if params 2 0 positive slope triggering will take place when the signal exceeds 2 5V Alternati
62. arams 3 Offset of destination data buffer params 4 Offset of destination channel buffer RETURNS DATA The data array will contain the counts The count range will be from 0 to 4095 if the card is in the unipolar mode or from 2048 to 2047 if the card is in the bipolar range The channel array will contain the channel number 0 to 15 if the card is in the single ended mode or 0 to 7 if in the differential mode ERROR CODES status 0 No error status 1 Driver has not been initialized with task O status 2 Invalid task number task gt 20 status 18 Transfer count params 2 is zero or negative status 26 Invalid memory segment EXAMPLE int task params 7 status these are globally declared variables int datbuf 100 chnbuf 100 these are globally declared variables task 9 params 0 100 number of conversions params 1 0x5000 passes segment to copy from params 2 0 starting position in segment is 0 params 3 FP_OFF datbuf pass offset of data buffer params 4 FP_OFF chnbuf pass offset of channel buffer a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 10 SET COUNTER 0 MODE Sets the operating mode of counter 0 NOTES 1 Counters 1 and 2 can also operate in any of these modes but this is not supported by the driver Counters 1 and 2 are set by Task 0 initialize to operate as divide by N counters as this is
63. as 61 eo bar pao pao pas DAS DA4 DA11 The eight most significant bits of the output For eight bit operations note that you can first write zeroes to the low bytes at base address 4 and base address 6 and all subsequent operations may then be performed with the high bytes only The following example shows how to output data in C and is readily translatable to other languages Since the D A s have 12 bit resolution data should be in the range 0 to 4095 decimal unsigned value this is our output variable value 2048 we will output half scale value 16 multiplying by 16 will left justify data outportb base_address 4 value amp Oxff extract and output lower byte of count outportb base_address 5 value 256 extract and output upper byte of count An assembly language routine is even simpler Assume AX contains the data and DX contains the card base I O address To write to D A 0 MOV CL 4 set up for four left shifts SAL AX CL left justify data OUT DX AX write to D A 0 The lengthy routine using direct register access can be avoided by using TASKS 15 or 16 of the standard driver TASK 15 outputs data to one D A and TASK 16 is optimized to update both D A s near simultaneously A typical output routine using the driver is task 16 output to both D A s params 0 2048 half scale for DAC 0 params 1 1024 quarter scale for DAC 1 a16drv 8task param
64. can be transferred to any 64K page of memory At the end of the transfer an interrupt is generated that shuts down the DMA hardware and signals completion of the operation This is the non recycle mode The second type of operation is an auto initialize or recycle mode where upon reaching the final word count the DMA controller automatically resets to the first memory location In this case the DMA is continuous and the word count specifies the length of the circular C 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL buffer that is created Information on the progress of a DMA transfer can be obtained using TASK 8 and data can be transferred from a memory buffer area to an array using TASK 9 C 4
65. ched from the list the list index is incremented The list index can be reset to the beginning of the point list by TASK 11 This task uses two buffers a data buffer and a point gain buffer Both buffers should be integer buffers of the same length The number of conversions must not exceed the length of the shortest buffer If you do other areas of computer memory may be corrupted cause unpredictable computer behavior The driver has no criteria to evaluate the validity of the pointer It is incumbent upon the application program to supply a valid buffer pointer The point and gain for each analog input is returned in the point gain buffer The point address and gain are packed into one integer with the point address in the upper eight bits and the gain in the lower eight bits The buffers must be declared globally or the driver will not be able to find their segment 5 This task has several functions each having their own required parameters 6 If the timers are used to generate the start conversion signals then they should be configured using TASK 14 SUBTASK 3 is used to disable interrupts before completion of the scan When the scan is complete the interrupts are disabled automatically 2 x 3 x 4 xw yo 7 x INPUT params 0 Subtask to perform 1 2 or 3 1 Initiate interrupt data acquisition params 1 Interrupt level IRQ params 2 Number of conversion to make params 3 Offset of the data buffer add
66. d gain are packed into one integer with the point address in the upper eight bits and the gain in the lower eight bits The buffers must be declared globally or the driver will not be able to find their segment 3 4 INPUT params 0 Offset of the data buffer address params 1 Offset of the point gain buffer address params 2 Number of conversion to make OUTPUT DATA params 3 Number of conversions completed The buffers will contain the conversions and the point gain data respectively ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 3 Card does not respond status 5 Point list error list empty EXAMPLE int task params 7 status these are globally declared variables int datbuf 100 chnbuf 100 these are globally declared variables task 8 params 0 FP_OFF datbuf pass offset of data buffer 6 10 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL params 1 FP_OFF chnbuf pass offset of point gain buffer params 2 100 number of conversions aa16drv FP_OFF 8task FP_OFF params FP_OFF 8status call the driver TASK 9 INTERRUPT DRIVEN DATA ACQUISITION Provides subtasks to perform buffered data acquisition using interrupts Sub task functions include initiating the interrupt conversions checking for completion and stopping the interrupt process NOTES 1 Each time a point is fet
67. de does not fall within the range of 0 through 8 Invalid reset code The reset code does not fall within the range of 0 through 5 Invalid counter timer number The counter timer number is not 0 1 or 2 Invalid mode The counter timer mode does not fall within the range of O through 5 Interrupt mode already set The interrupt mode can only be set up once A subsequent request has been made to set up the interrupt mode without previously resetting the mode Invalid interrupt number The interrupt number does not fall within the range of 2 through 7 No interrupt mode is set A request has been made to reset an interrupt mode that has not previously been set Invalid SUBTASK number SUBTASK specified is outside the valid range for agiven task Invalid data buffer Data buffer is not valid for interrupt driven data acquisition Invalid voltage range Voltage range specified should be either 5 or 10 volts Invalid curve specified The curve code letter specified is not a valid code Invalid A D channel number Invalid DMA channel must be 1 or 3 Invalid recycle mode should be 0 or 1 DMA page boundary error Bad segment for DMA transfer Invalid trigger mode should be 0 or 1 Number of transfer words too large D A output value is out of range The value is not between 0 and 4095 D A channel number is not 0 or 1 6 25 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted 6 26 ANALOG DIGITAL 1 0 C
68. e This is more than enough time even allowing for activity on higher priority DMA levels When the DMA controller receives a DRQ it issues a hold request to the CPU asking it to release the address and data bus to the DMA controller As soon as the CPU is able to do this one machine cycle it responds by returning a hold acknowledge HLDA to the DMA controller to tell it that it has the bus The DMA controller then supplies the memory C 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL address on the address bus issues a DACK to the I O device to tell it to place data on the data bus and also provides simultaneous I O read IOR and memory write pulses MEMW to effect the data transfer Control is then returned to the CPU for at least one machine cycle before another DMA cycle is possible The DMA controller handles a total of four DMA channels three of which are available on the expansion bus DMA FUNCTION SIGNALS SIGNALS PRIORITY LEVEL Memory Refresh Not on Bus Highest area Not Used DRQ1 DACK1 Floppy Disk s DRQ2 DACK2 Hard Disk XT DRQ3 DAck3 DMA level O performs a dummy read of each memory location every 15 microseconds thereby refreshing the dynamic memory It is important to not interfere with setup or operation of level O as this may lead to loss of memory and a computer crash i DMA level 1 is not committed to any internal device and is generally available on all PC s although if you have them in
69. e status of digital input bits IPO through IP3 NOTES 1 The value read may be 0 to 15 This represents a four bit binary value with each bit position corresponding to one digital input bit A 1 read means that IPO is high and the rest low a 3 read means that IPO and IP1 are high and the rest low 5 18 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL INPUT None RETURNS DATA params 0 Value read from the digital output bits ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 EXAMPLE int task params 7 status these are globally declared variables task 14 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver printf The digital input bits read d params 0 TASK 15 WRITE VALUE TO A SINGLE D A CONVERTER Writes a value to a given D A converter NOTES None 5 19 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL INPUT params 0 D A channel to write to O or 1 params 1 Write value O to 4095 RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 14 D A data out of range not between 0 and 4095 status 15 D A channel not 0 or 1 EXAMPLE int task params 7 status these are globally declared variables task 15 params 0 1 write to D A chann
70. e4 read back command counter 1 status printf d inporto BASEADDRESS 13 read the status byte for counter 1 Using Counter 0 as a Pulse Counter Note that the counters are down counters so when resetting them it s better to load them with a full count value of 65 535 rather than zero outportb BASEADDRESS 15 0x30 counter 0 mode O outportt BASEADDRESS 12 0xff counter 0 low load byte outportt BASEADDRESS 12 0xff counter 0 high load byte Reading Counter 0 outportt BASEADDRESS 15 0x30 counter 0 latch command read in both bytes of the latched value and combine into an integer value inportb BASEADDRESS 12 inporto BASEADDRESS 12 256 8 6 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL PROGRAMMING EXAMPLES USING THE A16DRV DRIVER In practice Tasks 10 through 12 of the A16DRV driver can be used to perform equivalent operations to the above examples with fewer programming steps For counting pulses the counter configuration is not of great importance because you will only be using the countdown capabilities of the counter Mode 2 is as good as any other choice for pulse counting task 10 set counter 0 mode task params 0 2 set counter 0 mode to 2 al6drv FP_OFF task FP_OFF params FP_OFF status call the driver As in the previous example load Counter 0 with a full scale count of 65 535 hex FFFF using Task 11 of the dr
71. easured in a single ended mode that voltage is added to the source signal thereby creating an error The best way to avoid ground loop errors is to use good wiring practice as described above Ifthis is not possible use of a differential measurement mode will minimize errors External Noise Voltages can be introduced onto signal lines via radiation and or capacitive coupling Ifthe differential measurement mode is used that noise appears in phase on both the high and low lines and the common mode rejection capability of this measurement mode will severely attenuate the noise In extreme cases twisted pair and or shielding will also reduce the noise problem INPUT RANGE AND RESOLUTION SPECIFICATIONS Resolution of an A D converter is usually specified in number of bits e 8 bits 12 bits etc Input range is specified in volts i e 0 5V 10 V 20 mV etc To determine the voltage resolution of an A D converter simply divide the full scale voltage range by the number of parts of resolution For example for a unipolar range of 0 10 volts a 12 bit A D resolves the input into 4096 parts Thus voltage resolution the weight of one bit is 2 44 mV For a bipolar range of 10V one LSB is worth 4 88mV If an amplifier is incorporated in the circuit providing gain then divide the voltage resolution by the gain of the amplifier For example a 12 bit A D with 10V full scale input range and an amplifier gain of 100 will provide an overall i
72. ed ANALOG OUTPUT The AD12 16 16F has two multiplying 12 bit digital to analog converters D A connected to output drivers capable of providing 5 mA current drive Each channel provides an output of 0 to 5VDC if the internal 5V reference voltage is used i e jumper from I O connector pin 8 to pin 10 DAC 0 and from pin 8 to pin 26 DAC 1 That on board reference voltage can be replaced by an externally supplied reference voltage biased AC or DC In this case the D A s will operate as multiplying D A s with two quadrant capability The maximum external reference voltage that can be applied is 10 volts INTERRUPTS AND DMA Interrupts can be initiated by completion of an A D conversion or by DMA terminal count if programmed by software Interrupt levels 2 through 7 are selectable via software Software control of direct memory access for transfer of A D conversion data to the computer is supported at either DMA level 1 or 3 as selected by switch S1 TRANSFERRING DATA INTO THE COMPUTER The AD12 16 16F has been designed using state of the art components to provide high data throughput using the DMA capabilities of the IBM PC family Direct memory access is the most satisfactory way to transfer data from the A D to memory at rates over 10 000 samples second At this speed program transfers through the CPU become difficult to handle in the short time available between conversions Also program transfers are subject to disruption by oth
73. een the low input and the low level ground at pins 28 or 29 The jumper connected between the low input and the low level ground effectively turns that differential input into a single ended input It s important to understand the difference between inputtypes how to use them effectively and how to avoid ground loops Misuse of inputs is the most common difficulty that users experience in applying and obtaining the best performance from data acquisition systems COMMENTS ON NOISE INTERFERENCE Noise is generally introduced into analog measurements from two sources a ground loops and b external noise In both cases use of good wiring practice will reduce and sometimes eliminate the noise A key point with regard to ground or return wiring is that in an analog digital system digital circuits should have a separate ground system from analog circuits with only a single common point The reason for separate ground busses is that digital circuits by their very nature generate considerable high frequency noise as they rapidly change state 7 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Ground Loops AC noise and DC offset can be added in series with a grounded signal source if the source ground is at a different potential than the A D s analog ground If there is an ohmic resistance between the source ground and the A D s ground the resultant current flow causes a voltage to be developed and a ground loop exists Ifthe signal is m
74. een the upper two posts selects 10 MHz and installing the jumper between the lower two posts selects 1 MHz DIGITAL I O As mentioned in CHAPTER ONE FUNCTIONAL DESCRIPTION digital input ports IPO through IP3 can be converted to output ports by installation of jumpers on the card These are jumpers D4 through D7 located to the left of the A D converter chip and adjacent to SIP resistor network RN2 SELECTING A BASE ADDRESS You need to select an unused segment of 16 consecutive I O addresses The base address will be the first address in this segment The base address may be selected anywhere on a 16 bit boundary within the I O address range 200 3FF hex providing that it does not overlap with other functions The following procedure will show you how to select the base I O address 1 Check the tables in FIGURES 2 2 and 2 3 for lists of standard address assignments and then check what addresses are used by any other I O peripherals that are installed in your computer Memory addressing is separate from I O addressing so there is no possible conflict with any add on memory that may be installed in your computer We urge that you carefully review the address assignment table before selecting a card address If the addresses of two installed functions overlap unpredictable computer behavior will result 2 x From this list or using the FINDBASE program select an unused portion of 16 consecutive I O addresses Note from the tables that t
75. el 1 params 1 2047 write half scale to this channel a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 16 WRITE TO BOTH D A CONVERTERS Performs a near simultaneous write to both D A channels NOTES 1 This task is an alternative to entering Task 15 twice in succession and is useful to drive X Y plotters resolvers analog controllers etc where the delays using Task 15 twice in succession would not produce ideal responses 2 If an error is detected in either channels load value neither channel will be updated INPUT params 0 Channel O write value O to 4095 params 1 Channel 1 write value O to 4095 RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 5 20 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL status 14 D A data out of range not between 0 and 4095 EXAMPLE int task params 7 status these are globally declared variables task 16 params 0 1024 write 1 4 scale to channel O params 1 2047 write 1 2 scale to channel 1 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 17 SET COUNTER 1 AND 2 RATE Sets the division ratios for Counter 2 and Counter 1 to produce a programmable output pulse rate for triggering the A D NOTES 1 The counter input clock frequency may be 1 MHz o
76. ented The list index can be reset to the start of the point list by using TASK 11 INPUT None OUTPUT DATA params 0 Point address converted params 1 Resulting conversion data params 2 Gain code used ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 3 Card does not respond status 5 Invalid point address or index EXAMPLE int task params 7 status these are globally declared variables 6 9 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL task 7 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 8 FETCH MULTIPLE BUFFERED CONVERSIONS Fetch multiple conversions from the point list using polling NOTES 1 Each time a point is fetched from the list the list index is incremented The list index can be reset to the beginning of the point list by Task 11 2 This task uses two buffers a data buffer and a point gain buffer Both buffers should be integer buffers of the same length The number of conversions must not exceed the length of the shortest buffer If you do other areas of computer memory may be corrupted cause unpredictable computer behavior The driver has no criteria to evaluate the validity of the pointer It is incumbent upon the application program to supply a valid buffer pointer The point and gain for each analog input is returned in the point gain buffer The point address an
77. er The 8254 is a flexible but powerful device that consists of three independent 16 bit presettable down counters Each counter can be programmed to any count between 1 or 2 and 65 535 in binary format depending on the mode chosen On the AD12 16 16F these three counters are designated Counter 0 Counter 1 and Counter 2 Counter 0 is un dedicated with the gate output and clock connections fully accessible via the I O connector Counter 0 is enabled by a discrete input and uses either an internal 100KHz clock or an external clock of up to 10MHz as selected by your software Counters 1 and 2 are cascaded together to form a 32 bit counter This dual counter can be enabled gated by program control or by an external signal as selected by your software and clocked by a jumper selected 1MHZ or 10MHZ precision crystal controlled internal source When the AIM 16P is used in conjunction with the AD12 16 16F counter 0 is not available for use OPERATIONAL MODES The 8254 modes of operation are described in the following paragraphs to familiarize you with the versatility and power of this device For those interested in more detailed information a full description of the 8254 programmable interval timer can be found in the Intel or equivalent manufacturers data sheets The following conventions apply for use in describing operation of the 8254 Clock A positive pulse into the counter s clock input Trigger A rising edge input to the
78. er interrupt processes in the computer Use of real time triggering of the A D plus DMA assures synchronism in sampling that is unaffected by other computer operations That capability is essential in applications such as signal analysis fast fourier transform and vibration and transient analysis where high data rates must be sustained for short intervals of time Thus AD12 16 16F s open l O mapped architecture together with three modes of data transfer polling via CPU interrupt via CPU and DMA provides considerable application flexibility 2 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL REFERENCE VOLTAGE AND POWER REQUIRED A 5 0 volt 0 05 reference voltage is available from the A D reference source for external use This reference output can source up to 5 mA of current The AD12 16 16F requires only 5VDC and 12VDC from the computer power supply An on board DC DC converter translates the 12VDC to low noise isolated 15VDC for the precision analog circuitry INPUT OUTPUT CONNECTIONS External connections can be made through a standard 37 pin male connector located at the rear of the computer AIM 16P s may be connected using special cabling as described in APPENDIX B UTILITY SOFTWARE Utility software is provided on CD with the AD12 16 16F card This software includes an illustrated setup and calibration program software drivers for QuickBASIC Turbo C and Turbo Pascal and sample programs Additionally a utility
79. er located at Base Address 10 If the least significant bit CO is high it allows the IPO signal to control the gates of Counters 1 and 2 This provides a means of disabling trigger pulses from the programmable interval timer to the A D until IPO is taken high If CO is low then IPO has no control over the timer The second bit C1 controls the source of clock inputs to Counter 0 If C1 is a zero then the external clock input is enabled If C1 is a one then the counter is connected to a stable 100KHz crystal controlled oscillator This control capability is useful if Counter 0 is used for pulse width measurements delay generation frequency synthesis or as a secondary timer TRIGGERING THE A D PERIODICALLY When you are using the A D converter on AD12 16 16F one of the key uses for the programmable interval timer is to provide start pulses for periodic sampling You can set up an output frequency by using Task 17 to load Counters 1 and 2 with the required divisors For example assume that a trigger rate of 8 3KHz is needed First work out the overall division ratio from either 1MHz or 10MHz depending on the setting of the CLOCK jumper on the card Assuming it is set for 1MHZ 1 000 000 8300 120 48 The closest frequency obtainable would be 1 000 000 120 8 333KHz Now divide the 120 between the two counters 3 40 120 task 17 load counters 1 and 2 task params 0 3 counter 1 divisor params 1 40
80. es task 17 params 0 100 number of conversions params 1 0x5000 use segment 5000 hope it isn t used params 2 1 use timers for conversion pulses params 3 0 do one cycle only params 4 3 use DMA level 3 params 5 5 use IRQ 5 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 18 TRANSFER DATA FROM MEMORY TO ARRAY Takes data from a segment extracts the channel and data and places each into their own array NOTES 1 Do not transfer more words than the array will hold The driver has no way to detect this condition This condition may cause unpredictable computer behavior Due to data re formatting that this task performs it is not a general purpose block move utility If using BASIC it is advisable to make the data array and channel array assign ments just before the CALL statement because declaring a new simple variable after making this assignment will dynamically relocate the arrays and upset operation of this task If you don t need channel data set params 4 O and channel data will be suppressed 2 x 3 4 INPUT params 0 Number of words to transfer params 1 Source memory segment to transfer from params 2 Starting position within source segment params 3 Offset of destination data buffer params 4 Offset of destination channel buffer RETURNS DATA The data array will contain A D c
81. es Cabling information is provided in Appendix B Normally the AIM 16P is connected to a single ended input configuration of the 2 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL AD12 16 16F However if interconnect cable noise becomes a problem or if long cables are necessary then the AIM 16P cards can be connected to the differential inputs of AD12 16 16F A differential connection allows better monitoring of remote locations because noise will be reduced by the common mode noise rejection capability of AD12 16 16F Note In this configuration the maximum number of inputs accommodated is 128 AIM 16P card address and channel address on the selected AIM 16P are controlled by digital outputs from the AD12 16 16F To use the programmable gain feature of the AIM 16P the AD12 16 16F digital inputs bits IP1 IP2 and IP3 must be converted to digital outputs This conversion is done by installing jumpers D5 D6 and D7 DISCRETE DIGITAL I O Four bits of TTL CMOS compatible digital input capability are provided Digital inputs IPO and IP2 have dual uses Input IPO provides an external trigger for the A D or can be used as the gate for Counter Timers 1 and 2 Input IP2 provides an input to enable Counter Timer 0 The digital input bits can be converted to output ports for AIM 16P applications as described in the INPUT SYSTEM EXPANSION section of this chapter When this is done you give up capability for gating Counter Timer 0 In this ca
82. f 3333 at Counters 1 and 2 to output a frequency of 3000 3 HZ In turn with 50 data points per cycle this would yield an output of 60 006 Hz pretty close to the desired 60 Hz Using TASK 17 set the timer task 17 set up counters 1 and 2 params 0 3 counter 2 divider params 1 1111 counter 1 divider a16drv amp task params amp status call the driver Next load an integer array with the table of output points Since the array is to output a 12 bit word it is also necessary to do scaling in this step With the D A connected to the internal 5V reference 0 corresponds to OV and 4095 corresponds to 4 9988V The following will dimension a 50 element integer array and load it with a sine wave centered around 2048 bits or 2 5V intindex datbuf 50 datbuf must be declared global compute the value for on complete cycle of a sine wave using 50 increments for index O index lt 50 index datbuf index 2048 int sin 2 2 14159 50 now use TASK 18 to output these values as a constant waveform task 18 waveform output task params 0 0 use D A channel 0 params 1 50 number of data points params 2 0 continuous cycle operation params 3 FP_OFF datbuf pass the offset of our buffer params 4 0 do not collect A D data a16drv amp task params amp status call the driver 9 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL
83. form of storage for the 12 bit data from the A D converter and the 16 bit data from the interval timer Therefore to conserve memory and disk space and to optimize execution time all data exchange via the CALL is through integer type variables This poses a programming problem when handling unsigned numbers in the range 32 768 to 65 535 If you wish to input or output an unsigned integer greater than 32 767 then it is necessary to work out what its 2 s complement signed equivalent is For example if 50 000 decimal is to be loaded into a 16 bit counter an easy way to convert this to binary is to enter BASIC and execute PRINT HEX 50000 This returns C350 which in binary form is 1100 0011 0101 0000 Since the most significant bit is a one this would be stored as a negative integer and in fact the correct integer variable value would be 50 000 65 536 15 536 B 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted B 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL APPENDIX C DIRECT MEMORY ACCESS IBM PC DMA STRUCTURE The DMA controller provides four prioritized direct memory access DMA channels Each channel has two control signals associated with it a DMA request DRQ and a DMA acknowledge DACK DMA provides for the bi directional transfer of data between I O devices and memory without passing the data through the CPU The advantage is a significant improvement in the speed of the data
84. g ACCES I O PRODUCTS INC Ma 10623 Roselle St San Diego CA 92121 Tel 858 En 9559 FAX 858 550 7322 ANALOG AND DIGITAL I O CARD AD12 16 16F USER MANUAL ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL NOTICES The information in this document is provided for reference only ACCES I O PRODUCTS INC does not assume any liability arising out of the application or use of the information or products described herein This document may contain or reference information and products protected by copyrights or patents and does not convey any license under the patent rights of ACCES nor the rights of others IBM PC PC XT and PC AT are registered trademarks of the International Business Machines Corporation Printed in USA Copyright 1994 by ACCES I O PRODUCTS INC 10623 Roselle Street San Diego CA 92121 1506 All rights reserved ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TABLE OF CONTENTS INSTALLATION ted cotton tie ee 1 1 CD INSTALLATION ive da ead be ee ee a be ee eed ea 1 1 3 5 INCH DISKETTE INSTALLATION 0000 00 00 eee ee 1 1 DIRECTORIES CREATED ON THE HARD DISK 0 00 0 00 00 1 2 FUNCTIONAL DESCRIPTION 2 0 00 2 ee tesa a pa DE Ea eda ee ee ee 2 1 ANALOG INPUTS 2 2 cecu anc ce ea ba as eee ee he a ee ee bee eG 2 1 INPUT SYSTEM EXPANSION posis pa eter eek a a a oe a ed ae A 2 1 DISCRETE DIGITAL WO wack cua ias de nip ei a a dale en nae a i 2 2 COUNTER TIMER 00400 ape E ae aed Sa es BAN
85. g the bipolar mode scale factors of 5000 and 5000 would be passed in the call to SUBTASK 3 10 TASK 10 does not initiate any conversions but sets up functions that will be performed automatically whenever conversion are done using tasks 6 7 8 or 9 INPUT params 0 Subtask to perform 1 2 3 or 4 1 Perform manual linearization of the given data params 1 ASCII code for lower case letter of curve or upper case T for reference junction params 2 counts see note 1 2 Assign thermocouple curve to a point address params 1 point address params 2 ASCII code for lower case letter of curve or upper case T for reference junction params 3 ASCII code for upper case letter of the desired temperature units C or F 3 Assign scaling factor to a point address params 1 point address params 2 Lower scaling term 6 14 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL params 3 Upper scaling term 4 Replicate a point address function assignment to a range of point addresses params 1 source address to replicate params 2 first point address in destination range params 3 last point address in destination range OUTPUT DATA SUBTASK 1 params 3 temperature in tenths of F params 4 temperature in tenths of C ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 5 Point error point address out of range status 13 Invalid subtas
86. he gate going high the counter output immediately goes high then goes low for one clock period at timeout producing a negative going strobe pulse The timeout is re triggerable i e a new cycle will commence if the gate goes high before a current cycle has timed out GENERATING INTERRUPTS WITH THE COUNTER TIMER The AD12 16 16F architecture does not allow you to directly generate an interrupt from the counter timer However you can set up the A D to be triggered by the counter timer and in turn have the A D generate an interrupt at the end of its conversion cycle a constant delay equal to the A D cycle Indirectly this accomplishes the desired result and you can install any desired interrupt routine to service the interrupt This is what the A16DRV driver does in Tasks 5 18 and 20 and provides examples of using the interrupt for servicing the A D outputting periodic wave forms on the D A s and block scanning channels Note also that it is possible to trigger the A D externally or by a programmed write to an I O port and invoke an interrupt at the end of A D conversion in the same way 8 11 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL D A CONVERTERS There are two separate double buffered 12 bit multiplying digital to analog converters on the AD12 16 16F card Each D A may be used with an on board fixed 5VDC reference voltage as a conventional
87. he sections 280 2EF and 330 36F are unused This address space is a good area to select a base address 3 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL from Also if you are not using a given device listed in the tables then you may use that base address as well For example most computers do not have a prototype card installed If your computer does not have one then base address 300 hex is a good choice for a base address 3 Finally make sure that the base address you have chosen has the last digit as 0 This insures that your base address is on a 16 bit boundary 3 5 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL FIGURE 2 3 STANDARD ADDRESS ASSIGNMENTS FOR 286 386 486 COMPUTERS Hex Range Usage 000 01F 020 03F 040 05F 060 06F 070 07F 080 09F 0A0 0BF 0CO 0DF OFO OF1 OF8 OFF 1FO 1F8 200 207 278 27F 2F8 2FF 300 31F 360 36F 378 37F 380 38F 3A0 3AF 3B0 3BF 3C0 3CE 3D0 3DF 3F0 3F7 3F8 3FF DMA Controller 1 INT Controller 1 Master Timer 8042 Keyboard Real Time Clock NMI Mask DMA Page Register INT Controller 2 DMA Controller 2 Clear Math Coprocessor Busy Reset Coprocessor Arithmetic Processor Fixed Disk Game l O Parallel Printer Port 2 Asynchronous Comm n Secondary Prototype Card Reserved Parallel Printer Port 1 SDLC or Binary Synchronous Comm n 2 Binary Synchronous Comm n 1 Monochrome Display Printer Local Area Network Color Graphic Monitor Floppy Diskette Cont
88. his cable adapter is given in APPENDIX B for those who wish to build their own Digital inputs bits IP1 IP2 and IP3 on the AD12 16 16F must be converted to digital outputs using jumpers D5 D6 and D7 if the programmable gain feature of the AIM 16P is to be used If not these bits may be used as desired 3 x THE POINT LIST CONCEPT Most functions of this driver work with a point list The point list is a list of point addresses in the order that you desire to have conversions performed A point address is a number specifying the channel of the AD12 16 16F and the AIM 16P The first 16 point addresses 0 15 refer to the AIM 16P channels for the AIM 16P attached to channel 0 of the AD12 16 16F The second 16 point addresses 16 31 refer to the 16 channels of the AIM 16P attached to channel 1 of the AD12 16 16F and so on Thus with 16 single ended A D channels a point address may be as large as 255 You may install point addresses into the point list in any order or with multiple entries for the same point address For example the order could be 15 12 12 11 9 255 1 1 0 etc The order that point addresses are installed in the point list is the order in which you call the driver to install them Each new entry is appended to the end of the list A point list index is used by the driver to keep track of which point address is the next to be converted After each conversion the index is incremented to the next position in the list When the
89. ination range aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 11 RESET FUNCTIONS Performs various reset function on the point list and function curve assignment tables Also provides a subtask to set the sample and hold settle time NOTES 1 SUBTASK 5 is provided to set the sample and hold settle time High speed 80286 and 80386 computers often will start a conversion before the sample and hold has had time to settle after changing a channel on the AIM 16P A value of 25 50 is usually sufficient for an 80386 machine INPUT params 0 Subtask to perform 1 2 3 4 or 5 1 Reset the point list index to first point address in the point list 2 Clears all point addresses from the point list 3 Resets the point list to the default conditions as described in TASK 0 4 Clears all curve and scaling assignments 5 Set the sample and hold settle time params 1 settle time count OUTPUT DATA None ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 13 Invalid sub task not between 1 and 5 EXAMPLE int task params 7 status these are globally declared variables task 11 params 0 5 set settle time sub task params 1 50 settle time count of 50 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 12 DIGITAL OUTPUT Writes to the digital output bits
90. interrupt DMA counter and external trigger functions 3 Initializes the point list to have point address for each channel of the AD12 16 16F with none for the AIM 16P i e point addresses 1 16 32 48 240 Initializes the function list for each point address to a gain code of 0 and no functions performed on conversion counts x 4 INPUT 6 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL params 0 Base Address params 1 Voltage range 5 or 10 volt OUTPUT DATA NONE ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 2 Invalid base address params 0 gt Ox3f0 or lt 0x200 status 3 Card does not respond status 15 Voltage range not 5 or 10 EXAMPLE int task params 7 status these are globally declared variables task 0 params 0 0x300 base address 300 hex params 1 5 voltage range is 5 volts aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 1 SET MULTIPLEXER SCAN LIMITS This task sets the multiplexer scan limits for the A D converter NOTES 1 This task is included for completeness but is not usually needed when the point 2 3 4 5 6 A y list is used If the default limits set in task O are acceptable then this task need not be called If the lower limit is greater than the higher limit the multiplexer will scan
91. is installed in the computer it is possible to change gain and thus range at the rear of the computer without removing the card from the computer The 0 5 GAIN jumper is located at the top of the card 3 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL The following table relates voltage range to the gain settings required As will be discussed later it s possible to establish a special range In that case the special range is designated USER in the following table DESIRED INPUT RANGE S5 GAIN SELECT UNIPOLAR UNIPOLAR BIPOLAR BIPOLAR x jumper in x jumper out x jumperin x jumper out PRES switches OFF Only switch 6 ON 0 1V 0 2V 11V 12V Only switch 5 ON 0 0 5V 0 1V 0 5V 11V Only switch 4 ON USER USER USER USER Only switch 3 ON When viewed from the connector end of the card a switch section is turned ON by moving the tab to the left Also switch sections are numbered 6 through 1 as viewed from top to bottom DMA LEVEL SELECT Slide switch S1 located immediately above the gold edge connector selects the direct memory access DMA level If you have floppy disk drives only in your computer set this switch to level 3 the right hand position If your computer contains a hard disk level 1 is preferable For a detailed description of DMA refer to Appendix D of this manual 3 2 ANALOG DIGITAL 1 0 CARD FIGURE 2 1 AD12 16 16F USER MANUAL OPTION SELECTION MAP Swiiches
92. iver While loading the counter counting can be inhibited by holding the gate input IP2 low task 11 set counter 0 count task params 0 Oxffff set counter 0 count to ffff hex 65535 a16drv FP_OFF task FP_OFF params FP_OFF status call the driver Next apply the number of pulses to be counted The gate input IP2 must now be high or can be taken high for some fixed time interval to control the number of pulses counted You can read the new count using TASK 12 of the driver task 12 read counter 0 count task params 0 1 indicates a latch before read task 11 set counter 0 count task params 0 Oxffff set counter 0 count to ffff hex 65535 a16drv FP_OFF task FP_OFF params FP_OFF status call the driver Note that in the counter read task TASK 12 params 0 specifies the type of read operation to perform If params 0 1 a counter latching operation is automatically performed This method of reading must be used if you want to read the counter while it is still counting See previous section titled READING AND LOADING THE COUNTERS If params 0 0 then a direct read of the counter is initiated and in this case the counter must be static or an erroneous reading can occur Upon return params 1 contains the counter contents 8 7 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL COUNTER TIMER ENABLE REGISTER This is a two bit write only regist
93. iver to indicate continuous or single pass was invalid 5 27 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL USING THE DRIVER WITH TURBO OR BORLAND C The following list shows you how to use the driver with Borland or Turbo C You may refer to any of the C example programs for further illustration Make sure that you use the proper driver name where required depending on which of the two drivers you use A G Include the AA16DRVC h or A16DRVC h header in your program This simple header provides a function prototype of the procedure call include aa16drvc h Declare the three variables for the driver globally int task params 7 status Make your assignment to these variables as desired for the function you wish to perform See the reference sections for details on each task Make the call to the driver passing the offset of each parameter aa16drv FP_OFF amp task P_OFF params FP_OFF status Create a project file within the Turbo C environment and add the name of your program with the C extension and the name of the driver with a OBJ extension You may use the CPP extension if you desire to work in C Select LARGE memory model under the compiler section of the options menu Compile and link the program USING THE DRIVER WITH MICROSOFT C To use the driver with Microsoft C version 6 0 add the following code to your application code as shown below asm push DS mov AX ES
94. k not between 1 and 4 status 16 Invalid curve EXAMPLE int task params 7 status these are globally declared variables task 10 manually linearize a value params 0 1 manual linearization subtask params 1 116 ASCII t for t type thermocouple params 2 1801 counts 16 at gain of 200 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver values returned in params 3 and params 4 assign curve to a point address params 0 2 curve assignment subtask params 1 0 first point address on first AIM 16P params 2 84 ASCII T for reference junction params 3 70 ASCII F for degrees F aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver assign a range of 5 volts in millivolt increments to a point address params 0 3 range assignment subtask params 1 22 point address to assign params 2 5000 lower range params 3 5000 upper range aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver replicate the assignment for point address 22 to point addresses 23 40 params 0 4 replication subtask params 1 22 source point address to replicate 6 15 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL params 2 23 lower point address in destination range params 3 40 upper point address in dest
95. le at the input port unless the lines are externally connected In addition two of the input port lines do double duty IPO is the entry point for external A D triggers and IP2 provides gate inputs for Counter 0 in the Counter Timer These secondary functions may or may not be used depending on the application In addition there are jumpers on the card that permit conversion of the input ports to outputs on a bit by bit basis Jumpers D4 through D7 Base 3 Write Write digital output OPO OP3 These are the four bits of digital output OP4 OP7 These are optional additional digital output NOTE OP4 through OP7 are only available if jumpers D4 through D7 are installed on the card Base 3 Read Read digital input 4 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL IPO IP3 These are the four bits of digital input NOTE These are only available if the jumpers D4 through D7 are NOT installed on the card X These bits are don t care It is good programming practice to set these bits to 0 ANALOG OUTPUTS D A Converter DAC registers are write only registers and require a low byte high byte write sequence to load the 12 bit DAC s Note that the registers are double buffered so that the DAC s are not updated until the second high byte is written Thus you can write the low bytes to DAC s 0 and 1 first and then the high bytes to DAC s 0 and 1 This ensures near simultaneous transition of the analog outputs Data are tr
96. lows task The number of the task to perform A reference with a list of tasks for each driver follow for the standard driver and in the next chapter for the AIM 16P driver parameters This is an array of integers which contains information required by the driver The reference chapter for each task defines what values need to be passed The array should hold seven integers status An error code is returned in this variable A zero is returned if there is no error When calling the procedure certain important requirements must be met A The variables must be declared as global If they are not the driver will not be able to find their data segment Most programming languages only use the data segment for global variables which is permanent storage Variables declared in procedures are usually allocated on the stack which is temporary storage The driver expects parameters to be integer type variables and will write to and read from the variables on this assumption The driver will not function properly if non integer variables are used in the call The variables should be passed by reference The driver expects offsets of the variables so that data may be returned when required The passed variables are positional That is the variables must be specified in the sequence task parameters status Their location is derived sequentially from the variable pointers on the stack The driver will not function
97. ly assign the curve T to this point address using SUBTASK 2 Any other point addresses on the AIM 16P will now be junction compensated automatically by the driver each time a point address is converted The reference junction circuit on the AIM 16P card generates 24 4 mV C The counts read in at a gain of 1 are 2 44 millivolts count Thus each count represents 0 1 C When thermocouple curves are assigned to a point address it is also required to set that point address to a particular gain using TASK 4 These gains are presented in the following table Note that two gain codes are presented for each thermocouple type the one you use will depend on the setting of the G 2 switch on the AIM 16P If G 2 is OFF use the lower gain code if G 2 is ON then use the higher gain code 6 13 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 6 The 5 volt range should be used with thermocouple inputs T C TYPE GAIN GAIN CODE UVOLTS COUNT b 200 5 6 12 207 RTD TYPE GAIN GAIN CODE UVOLTS COUNT a w s 24 414 as 24 414 7 For platinum RTD s there are two curves a for sensors with 392 alpha and u for sensors with 385 alpha 8 Temperature is returned in increments of 1 10th degree For example 100 degrees would be returned as 1000 9 SUBTASK 3 can be used to force the driver to return values in units determined by the user rather than counts For example you might desire values returned in millivolts In such a case assumin
98. mber of delay counts loaded The Counter 0 clock is supplied by the on board 100KHz oscillator C1 of the base address 10 register should be a 1 The output of counter 0 is con nected to Counters 1 and 2 gate at digital input IPO Counters 1 and 2 are used as a programmable trigger source for the A D CO of the base address 10 a 1 When Counter 0 is gated it will count and its output will go high after it has counted down This high will then gate Counters 1 and 2 to count supplying trigger pulses to the A D 8 10 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Programmable One Shot The counter need only be loaded once The time delay is initiated when the gate input goes high At this point the counter output goes low If the gate input goes low counting continues but a new cycle will be initiated if the gate input goes high again before the timeout delay has expired i e is re triggerable At the end of the timeout the counter reaches zero and the counter output goes high That output will remain high until re triggered by the gate input Software Triggered Strobe This is similar to Pulse on Terminal Count except that after loading the output goes high and only goes low for one clock period upon timeout Thus a negative strobe pulse is generated a programmed duration after the counter is loaded Hardware Triggered Strobe This is similar to Programmable One Shot except that when the counter is triggered by t
99. nd can aid in troubleshooting if problems arise CALIBRATION SOFTWARE The following procedure is brief and is intended for use in conjunction with the calibration part of the SETUP program 1 Start the calibration program by typing SETUP and press the ENTER key at the 2 3 4 5 6 7 8 x x xw gt DOS prompt Use the relevant menu selections to set the switches and jumpers for the manner in which the card will be used i e number of channels gain and polarity These settings are used by the calibration portion of the program Note The card must be in the 16 channel single ended configuration for this calibration procedure Use the arrow key to select option 7 Calibrate then press the ENTER key The program displays a message about the initial settings Press any key to continue Following the instructions on the screen perform the Zero adjustment Press ENTER when complete The program will now compute the full scale adjustment voltage Apply this voltage as instructed and make the full scale adjustment Press ENTER when complete Now use the 5V reference voltage on the card or your own reference voltage as shown on the screen Perform DACO zero adjustment as instructed and press ENTER when complete Now perform the DACO span adjustment Steps 7 and 8 will be repeated by the program for zero and span adjustment of DAC1 10 This completes the calibration procedu
100. not initialized Task 0 must be performed before attempting any other task Task number out of range Must be Task 0 through 20 Base address out of range Must be between hex 200 and hex 3F0 Interrupt level out of range Must be between 2 and 7 DMA level must be 1 or 3 Multiplexer scan limits out of range for differential configuration Must be between O and 7 Multiplexer scan limits out of range for single ended configuration Must be between O and 15 Not Used A D timeout error hardware error no EOC Counter division ratios cannot be 0 or 1 Number of conversions negative Counter mode out of range Must be between 0 and 5 Digital output data out of range Must be between 0 and 15 D A data out of range Must be between 0 and 4095 D A channel number out of range Must be 0 or 1 Counter read operation must be 0 or 1 Start convert number is a negative number Word count must be a positive number greater than zero Trigger mode must be either 0 or 1 DMA Interrupt operation already active DMA page wrap around Hardware failure or installation error Base address set wrong Trigger channel inconsistent with configuration Must be between 0 and 7 for differential or between 0 and 15 for single ended Trigger source out of range Slope data must be 0 or 1 Bad segment address Segment of data buffer passed to driver was too large Bad cycle flag Value passed to dr
101. nput resolution of about 49 uV CURRENT MEASUREMENTS Current signals can be converted to voltage for measurement by the A D converter by addition of a shunt resistor installed across the input terminals For example to accommodate 4 20 mA current transmitter inputs connect a 2500 shunt resistor across the A D input terminals The resultant 1 5V signal can then be measured The ACCES STA 37 screw terminal accessory board for example includes a breadboard area with plated through holes that allow insertion of shunt resistors If an AIM 16P multiplexer expansion board is being used pre wired pads are provided on the AIM 16 If all the inputs are 4 20mA range current inputs from current transmitters then there is a configuration of the multiplexer expansion board called AIM 16IP That model includes the shunt resistors and has offset and gain set such that the live zero is compensated for and the full 12 bit resolution of the A D is realized 7 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Note Accuracy of measurement will be directly affected by the accuracy of these resistors Accordingly precision resistors should be used Also if the ambient temperature will vary significantly these precision resistors should be low temperature coefficient wire wound resistors MEASURING LARGE VOLTAGES Voltages larger than the input range ofthe A D can be measured by using a voltage divider As above it is necessary to use precision resisto
102. nter 0 Base Address 13 Read Write Counter 1 Base Address 14 Read Write Counter 2 Base Address 15 Write to Counter Control register The counters are programmed by writing a control byte into a counter control register at Base Address 15 The control byte specifies the counter to be programmed the counter mode the type of read write operation and the modulus The control byte format is as follows Be es ea es e m eo SCO RW1 RWO M1 MO BCD SCO SC1 These bits select the counter that the control byte is destined for SC1 Sco Function Program Counter 0 Program Counter 1 Program Counter 2 Read Write Cmd See section on READING AND LOADING THE COUNTERS RWO RW1 These bits select the read write mode of the selected counter RW1 RWO Counter Read Write Function Counter Latch Command Read Write LS Byte Read Write MS Byte Read Write LS Byte then MS Byte 200 200 8 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL MO M2 These bits set the operational mode of the selected counter 002200 BCD Set the selected counter to count in binary BCD 0 or BCD BCD 1 READING AND LOADING THE COUNTERS If you attempt to read the counters on the fly when there is a high input frequency you will most likely get erroneous data This is partly caused by carries rippling through the counter during the read operation Also the low and high bytes are read sequentially rather than
103. o use the program and driver in the environment you must link a Quick Library Perform the following command from the command line LINK Q A16DRV OBJ A16DRV QLB BQLB45 LIB ENTER G Now load the Quick Library when starting the environment 5 30 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL QB L A16DRV QLB ENTER H Use the start command from the run menu to execute the program To prepare an EXE file from the command line use the following compile and link commands BC o YOURPROG ENTER LINK YOURPROG A16DRV ENTER 5 31 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL AD12 16 16F WITH AIM 16P DRIVER REFERENCE This chapter provides detailed information on the functions available from the AD12 16 16F with AIM 16P driver The chapter is divided into four sections the first is a section detailing the use of this driver The second is a task summary third is the task reference and last is an error code summary USING THE DRIVER HARDWARE INFORMATION The following should be considered when using this driver 1 The AIM 16P rather then the AIM 16 must be used Because the AD12 16 16F does not supply 12 volts to the external connector the AIM 16P has an on board 15 volt power supply 2 Thecable connection between the AD12 16 16F and the AIM 16P requires a special cable adapter ACCES part number CA37 The connection diagram for t
104. of 0 005131 for the positive side Thus by using two polynomials you have made the positive side very accurate and dramatically improved the negative side Accuracy of the negative side can be further improved by adding points For example add the following pairs to the negative side of the polynomial for a type T thermocouple x 6 181 5 167 4 051 2 633 f x 250 175 125 If you run the new data the QUALITY is improved to 69 555611 but still perhaps not as good as you would like Thus you may use the QUALITY as a means to determine how good the polynomial is You can experiment with both order and number of data points until you are satisfied with the solution Incidentally this example also shows that the smaller the range of x values the better the solution The computational method used is a least squares solution using Gauss Elimination with partial pivoting to improve accuracy APPENDIX B BASIC INTEGER VARIABLE STORAGE Data are stored in integer variables type in 2 s complement form Each integer variable B 1 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL uses 16 bits or two bytes of memory Sixteen bits of binary data is equivalent to O to 65 535 decimal but the 2 s complement convention interprets the most significant bit as the sign bit so the actual range is 32 768 to 32 767 Numbers are represented as follows LOW BYTE B B 3 32767 10000 Integer variables are the most compact
105. operations Data may be retrieved by Task 9 during or after Task 6 operation and will not alter the memory On completion of an interrupt operation the selected level of the 8259 interrupt mask register is disabled and the tristate interrupt drivers of the AD12 16 16F are placed in the high impedance state This allows multiple AD12 16 16F s to use the same interrupt level as long as they do so sequentially Note that any old interrupt vectors are not restored by the driver after AD12 16 16F has finished using the interrupt Upon completion of a DMA operation the tristate DMA request drivers of the AD12 16 16F are placed in the high impedance state This allows more than one AD12 16 16F to use the same DMA level as long as they do so sequentially 5 11 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 7 lf you are using the programmable interval timer note that you cannot exit from Task 5 until the signal at IPO is taken high INPUT params 0 Number of conversions to make params 1 Segment of memory to store data params 2 Trigger source 0 External trigger input Conversions start on positive transitions of the IPO input and continue until the word count is reached 1 Programmable interval timer In this case IPO should be held low until you want to start conversions After IPO goes high this input will have no further effect Conversions start on each positive transition of the output of counter 2 therefore you must set up co
106. oughput approaching 34 000 samples per second 6 6 19 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL INPUT params 0 Offset of the data buffer address params 1 Offset of the point gain buffer address params 2 Number of conversion to make OUTPUT DATA params 3 Number of conversions completed The buffers will contain the conversions and the point gain data respectively ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 3 Card does not respond status 5 Point list error list empty EXAMPLE int task params 7 status these are globally declared variables int datbuf 100 chnbuf 100 these are globally declared variables task 16 params 0 FP_OFF datbuf pass offset of data buffer params 1 FP_OFF chnbuf pass offset of point gain buffer params 2 100 number of conversions aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 17 DO N A D CONVERSIONS USING DMA Perform N conversions using DMA and store the results in a specified segment of memory NOTES 1 DMA is performed purely by the system and the AD12 16 16F is a background operation and is very fast Throughput is limited mostly by the settle time of the Sample Hold amplifier and the A D converter The AD12 16 can provide a maximum of about 60 000 conversions per second The AD12 16F uses a faster
107. ounts The count range will be from 0 to 4095 if the card is in the unipolar mode or from 2048 to 2047 if the card is in the bipolar mode 6 22 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL The channel array will contain the channel number 0 to 15 if the card is in the single ended mode or 0 to 7 if it is in the differential mode ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 2 Invalid task number status 7 Word count too large status 23 Segment offset too large EXAMPLE int task params 7 status these are globally declared variables int datbuf 100 chnbuf 100 these are globally declared variables task 18 params 0 100 number of conversions params 1 0x5000 passes segment to copy from params 2 0 starting position in segment is 0 params 3 FP_OFF datbuf pass offset of data buffer params 4 FP_OFF chnbuf pass offset of channel buffer aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 19 TERMINATE DMA INTERRUPT OPERATION Terminates DMA operation NOTES None INPUT None RETURNS DATA None ERROR CODES status 0 No error status 1 Invalid task number EXAMPLE int task params 7 status these are globally declared variables task 19 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver
108. ource 0 External trigger input Conversions start on positive transitions of the IPO input and continue until the word count is reached 1 Programmable interval timer In this case IPO should be held low until you want to start conversions After IPO goes high this input will have no further effect Exit occurs when the word count is reached params 3 Cycle Recycle operation 0 One cycle After completion of the number of conversions specified interrupts are disabled and operation status is set to zero 1 Recycle Data are continuously written to the same memory params 0 corresponds to the memory buffer length Operation will continue until stopped by TASK 19 params 4 DMA level 1 or 3 params 5 IRQ level 2 through 7 RETURNS DATA Data are stored in the segment address passed starting at offset 0 The data may be converted and placed in an array by using TASK 18 ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 7 Number of conversions is 0 or negative status 10 Interrupt or DMA already active status 11 Invalid interrupt number status 18 Invalid DMA channel status 19 Invalid recycle mode status 20 DMA page error status 21 Segment page wrap around error 6 21 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL status 22 Invalid trigger mode EXAMPLE int task params 7 status these are globally declared variabl
109. piecewise linearization using look up tables and use of a mathematical function to approximate the non linearity Amongst the mathematical methods polynomial expansion is one of the easiest to implement The utility program POLY EXE allows you to generate up to a 10th order polynomial approximation For most practical applications a fifth order polynomial approximation is usually adequate Before you start the program have the desired input output data or calibration data handy This will be in the form of x and f x values where x is the input to your system and f x is the resulting output To run the program type POLY and lt ENTER gt at the command line The program will then prompt you for the desired order of the polynomial then the number of pairs that you wish to use to generate the polynomial You then enter the data pairs and the polynomial is computed and displayed For example given the following data points let s generate a 5th order polynomial to approximate this function The order of the polynomial that you desire will be 5 and the number of data points that you enter will be 11 After the data points are entered the program gives the following output For the polynomial f x C 0 C 1 x C 2 x C 3 x C 4 x C 5 x the coefficients will be COEFFICIENT 5 0 003151 COEFFICIENT 4 0 081942 COEFFICIENT 3 0 740668 COEFFICIENT 2 2 635998 COEFFICIENT 1 2 816607 COEFFICIENT 0 2 956044
110. plifier with switch selectable gains of 10 5 2 1 and 0 5 to provide voltage ranges of 1 2 5 and 10 volts unipolar and 0 5 1 2 5 5 and 10 volts bipolar In addition you can set up a special range by installing a single gain setting resistor AD12 16 uses an industry standard 12 bit successive approximation analog to digital converter A D with a sample and hold amplifier input Under ideal conditions throughputs of up to 50 000 conversions per second are possible AD12 16F uses a faster A D and throughputs up to 100 000 conversions per second are possible A D conversions may be initiated in any one of three ways a by software command b by on board programmable timer or c by direct external trigger In turn data may be transferred to the computer by any of three software selectable methods a by polling for EOC End Of Conversion b by EOC interrupt or c by direct memory access DMA INPUT SYSTEM EXPANSION The card can be used with up to 16 external AIM 16P analog input expansion cards This necessitates converting some digital inputs to digital outputs as will be described later Each AIM 16P card provides capability for 16 differential inputs and thus there can be up to a maximum of 256 inputs per combination of AIM 16P s and AD12 16 16F The first AIM 16P is connected to the AD12 16 16F by a special cable adapter and ribbon cable any additional AIM 16P cards are daisy chained to each other by ribbon cabl
111. properly if arithmetic functions x etc are specified within the variable list bracket TASK SUMMARY TASK 0 Initialize the card set the base address interrupt level and the DMA level 5 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 1 Set the multiplexer low and high scan limit TASK 2 Return the next channel to be converted and the multiplexer scan limit setting TASK 3 Perform a single A D conversion Return data and increment the multiplexer address Polled conversion speed is slow and the operation is foreground TASK 4 Performan N conversions scan Data are transferred to an integer array Speed is medium and the operation is foreground TASK 5 Perform an N conversions scan after trigger into a memory segment using interrupts Speed is medium and operation is in the background TASK 6 Perform an N conversions scan after trigger into a memory segment using DMA Speed is fast and operation is in the background TASK 7 Disable DMA Interrupt operation of Tasks 5 6 18 or 20 TASK 8 Report status of DMA Interrupt operation initiated by Tasks 5 6 18 or 20 TASK 9 Transfer data from memory segment to integer array TASK 10 Set Counter 0 operating configuration TASK 11 Load Counter 0 data TASK 12 Read Counter 0 TASK 13 Output to digital outputs OPO OP3 TASK 14 Read digital inputs IPO IP3 TASK 15 Output data to single D A channel TASK 16 Output data to both D A channels TA
112. r DO NOT get inputs mixed up with the AC line An inadvertent short can instantly cause extensive damage ACCES cannot accept liability for this kind of accident As an aid to avoid this problem a Avoid direct connection to the AC line b Make sure that all connections are secure so that signal wires are not likely to come loose and short to high voltages c Use isolation amplifiers and transformers where necessary There are two types of ground connections on the rear connector of AD12 16 16F These are called Power Ground and Low Level Ground Power ground is the noisy or dirty ground that is meant to carry all digital signals and heavy power supply currents Low Level Ground is the signal ground for all analog input functions It is only meant to carry signal currents less than a few milliamperes and is the ground reference for the A D converter Due to connector contact resistance and cable resistance there may be many millivolts difference between the two grounds even though they are connected together and to the computer and power line grounds on the AD12 16 16F card 7 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL COUNTER TIMER OPERATIONS The AD12 16 16F contains a type 8254 programmable counter timer which allows you to implement such functions as a Real Time Clock Event Counter Digital One Shot Programmable Rate Generator Square Wave Generator Binary Rate Multiplier Complex Wave Generator and or a Motor Controll
113. r 10 MHz as selected by a 3 gt jumper on the card Use the following computation to determine the counter frequency in hertz a 1 000 000 counter 2 load counter 1 load when the clock frequency jumper is in the 1 MHz position b 10 000 000 counter 2 load counter 1 load when the clock frequency jumper is in the 10 MHz position Counters 1 and 2 are set to divide by N mode 2 and to output 1 KHz 10 KHz if jumpered for 10 MHZ clock by the initialization sequence of Task 0 The minimum divisor for either counter is 2 the maximum is 65 535 Thus possible pulse rates are 250 KHz to less than one pulse per hour with a 1 MHZ clock and ten times those rates with a 10 MHz clock input If you wish to perform conversions in the 10 100 KHz range use of the 10 MHz will give a greater choice of selectable rates because the clock frequency is divided by the product of two integers INPUT params 0 Counter 2 load value params 1 Counter 1 load value RETURNS DATA None 5 21 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 10 A counter has a divisor of 1 or 0 EXAMPLE int task params 7 status these are globally declared variables task 17 params 0 10 Set the tow counters to params 1 1000 divide by 10000 a16drv FP_OFF amp task FP_O
114. r than 32 767 set the integer variable to X 65 536 For example 40 000 would be entered as 25 536 2 If Task 10 has not been entered prior to Task 11 the mode will default to 0 which is suitable for pulse and event counting INPUT params 0 Counter O load value 5 16 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 EXAMPLE int task params 7 status these are globally declared variables task 10 params 0 10000 set counter 0 load value a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 12 READ COUNTER 0 Reads the current count of counter 0 NOTES 1 Since the counter is a 16 bit device counts as high as 65 535 are possible In BASIC integer variables are signed 16 bit words i e can have values between 32 767 and 32 767 If a negative number is returned you may convert it to the proper positive value by adding 65 536 to it For example if 8000 is returned add 65 536 to it to get 57 536 Read type 0 does not latch the counter Therefore if the counter is still running an erroneous count may result Use read type 1 in these situations 3 Neither type of read will affect counter data or operation 2 x INPUT params 0 Counter read type 0 Read without latch while counter is running
115. re 3 9 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL PROGRAMMING THE AD12 16 16F This section provides you with information on how to program the AD12 16 16F First information is provided on how to program the card using direct register access Following this is information on using the device drivers provided with the AD12 16 16F At the lowest level the AD12 16 16F can be programmed using direct I O input and output instructions In BASIC these are the INP X and OUT X Y functions Assembly language and most high level languages have equivalent instructions Use of these functions usually involves formatting data and dealing with absolute I O addresses Although not demanding this can require many lines of code and requires an understanding of the devices data format and architecture of the AD12 16 16F AD12 16 16F REGISTER ADDRESS MAP The AD12 16 16F uses 16 consecutive addresses in I O space as follows REGISTER ADDRESS READ FUNCTION WRITE FUNCTION BASE ADDRESS 0 A D Low Byte and Channel Number Start A D Conversion BASE ADDRESS 3 Four Bit Digital Input Four Bit Digital Output BASE ADDRESS 4 Not used DAC 0 Low Byte BASE ADDRESS 7 Not Used DAC 1 High Byte BASE ADDRESS 8 Card Status Clear Interrupt BASE ADDRESS 11 Not Used Not Used BASE ADDRESS 12 Counter 0 Count Value Counter 0 Load
116. ress params 4 Offset of the point gain buffer address params 5 A D trigger mode 0 Start A D on each positive transition of the IPO TRGO pin 1 Use counters 1 and 2 to supply the A D trigger 2 Check for end of interrupt scan 3 Disable the interrupt operation OUTPUT 6 11 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL DATA SUBTASK 1 The buffers will contain the conversions and the point gain data respectively SUBTASK 2 Params 1 0 if scan complete task number if still in progress ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 3 Card does not respond status 5 Point error point list is empty status 7 Invalid number of conversions not between 1 and 32767 status 10 Background task already active status 11 Interrupt not between 2 and 7 status 12 Interrupt already unassigned SUBTASK 3 status 13 Invalid subtask not 1 2 or 3 status 14 Invalid trigger mode not 1 or 2 EXAMPLE int task params 7 status these are globally declared variables int datbuf 100 chnbuf 100 these are globally declared variables task 9 params 0 1 initiate interrupt scan params 1 5 use IRQS params 2 100 do 100 conversions on this scan params 3 FP_OFF datbuf pass offset of data buffer params 4 FP_OFF chnbuf pass offset of point gain buffer aa16drv FP_OFF amp task FP_
117. ress for the 6th point in the point list aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 4 ASSIGNS GAIN CODE TO RANGE OF POINT ADDRESSES Assigns a given gain code to a given range of point addresses NOTES 1 The first point address of the range must be less than or equal to the last point address of the range To assign a gain code to a single point address make the first and last point address equal 2 These gain code settings are only meaningful if the AIM 16P is being used 3 The following are the possible gain codes GAIN AIM 16P OUTPUT RANGE SWITCH SETTINGS 18925 0 GAIN 1 GAIN 0 5 1 GAIN 2 GAIN 1 6 6 G 2 OFF G 2 ON ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 2 GAIN 10 GAIN 5 3 GAIN 50 GAIN 25 4 GAIN 100 GAIN 50 GAIN 200 GAIN 100 aa GAIN 400 GAIN 200 7 GAIN 1000 GAIN 500 8 AUTO RANGE 4 A gain code of 8 indicates an auto range channel When the point address is read the driver will first read at a gain of 2 gain code 1 and from this reading determine the best gain to use for the second reading to achieve the best resolution didda INPUT params 0 First point in point address range params 1 Last point in point address range params 2 Gain code to assign OUTPUT DATA None ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized
118. roller Asynchronous Comm n Primar 3 6 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL SETTING THE BASE ADDRESS The AD12 16 16F base address is selected by DIP switch S4 located in the lower right hand portion of the card directly adjacent to the I O connector Switch S4 controls address bits A4 through A9 Bits AO through A3 are used for the 16 address locations in I O space required by the AD12 16 16F The following procedure will show you how to set the base address See FIGURE 2 4 BASE ADDRESS EXAMPLE below for a graphic representation of this example 1 We will use base address 300 hex as an example Determine the binary representation for your base address In our example 300 the binary representation is 11 0000 0000 The conversion multipliers for each binary bit are contained in FIGURE 2 4 for reference N Locate switch S on the lower right side of the card next to the I O connector Note there are 6 switches which will be used to set the first six bits in the binary representation from step 1 The last 0 is assumed and therefore need not be set 3 x Note from FIGURE 2 4 that switch position A9 corresponds to the most significant bit in your binary representation For each bit in your binary representation if the bit is a one turn the corresponding switch off if the bit is zero turn the corresponding switch on FIGURE 2 4 BASE ADDRESS EXAMPLE Hex representation 3 0 0 Binary representation
119. rs Also if the raw voltage is a direct analog of a parameter being measured then it will be necessary to apply a scale factor in software in order to arrive at the correct engineering units ADDING MORE ANALOG INPUTS You can add sub multiplexers to any or all of the analog inputs of AD12 16 16F ACCES AIM 16P provides capability for 16 channels per input plus a common instrumentation amplifier Up to 16 AIM 16P s can be added to one AD12 16 16F providing a total input capability up to 256 channels The first eight AIM 16P require a cable adapter ACCES part number CA37 1 If additional AIM 16P s are required then a modified cable adapter is required ACCES part number CA37 2 See APPENDIX B CABLING AND CONNECTOR INFORMATION for a description of these cable adapters When a sub multiplexer is added it is not possible to operate AD12 16 16F in the fast DMA mode because of need to drive the sub multiplexer board address through the digital output port However you may use some of the AD12 16 16F channels as direct inputs for DMA purposes while using other channels for slower speed inputs through the AIM 16P s The AIM 16P is best suited to handling high gain low rate of change inputs from sensors such as ther mocouples pressure transducers etc 7 3 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL PRECAUTIONS NOISE GROUND LOOPS AND OVERLOADS Unavoidably data acquisition applications involve connecting external things to the compute
120. rsion When conversion is complete at the Stop channel High Channel Number the cycle repeats starting with the Start channel Low Channel Number When 4 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL writing to this register the multiplexer is always automatically initialized to the Start Channel number e HMA3 HMA2 HMA1 ENN imao imas imaz LMA2 L LMA1 inaa LMAO LMA3 Binary representation of the starting channel number LMAO is the least significant bit HMAO HMA3 Binary representation of the ending channel number HMAO is the least significant bit To perform conversions on a single channel the Start channel and the Stop channel numbers should be made equal to the desired channel number If the AD12 16 16F is to be operated in the 8 channel differential mode you should ensure that the HMA3 and LMA3 bits are zero Also when using the differential mode you should not set the lower scan limit greater than the upper scan limit If you do this when the upper scan limit is reached the multiplexer will try to cycle to channel 15 which is an undefined condition You can determine the multiplexer operating mode by reading bit 5 of the card status register at base address 8 DIGITAL I O Digital I O available consists of two 4 bit ports a 4 bit input port IPO IP3 and a 4 bit output port OPO OP3 These ports share the same I O address but are essentially independent i e data written to the output port isn t readab
121. rt input IPO are ANDed so that CO enables external triggers and counters 1 and 2 a counting when both are high This allows the set up of a timer driven DMA or interrupt process and subsequent enabling of operations either by software or by a signal on the external A D start line IPO C1 C1 in conjunction with the Counter 0 Input Gate at digital input IP2 controls clock pulses to Counter 0 When both are high an on board crystal controlled 100 KHz clock source is connected to the counter CLOCK IN GATE and COUNTER OUT are all available at external connections So if C1 is set low the internal 100 KHz clock is disabled and an external clock source can be applied using the CLOCK IN 0 pin In this mode Counter 0 can be used as an event counter Or if the GATE input is connected to a time base e g COUNTER 2 OUTPUT Counter 0 can be used to determine frequency Base 12 Write Read Counter 0 read or write When writing this register is used to load a counter value into the counter The transfer is either a single or double byte transfer depending on the control byte written to the counter control register at Base 15 If a double byte transfer is used then the least significant byte of the 16 bit value is written first followed by the most significant byte When reading the current count of the counter is read The type of transfer is also set by the control byte Additional information about the type 8254 counters is presented in
122. s task 5 params 0 0 first point address in range params 1 31 last point address in range two AIM 16Ps aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 6 FETCH DATA FROM A POINT ADDRESS Perform a conversion on the point address indicated NOTES 1 This task does not use the point list If you wish to fetch data from the next point in the point list then use TASK 7 This task does not use any assigned gains or TASK 10 functions 2 Point addresses that are not on a 16 boundary 0 16 32 48 etc are only meaningful if the AIM 16P is being used INPUT params 0 Point address to fetch data from 6 8 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL OUTPUT DATA params 1 Resulting conversion params 2 Gain code used ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 3 Card does not respond status 5 Invalid point address or index EXAMPLE int task params 7 status these are globally declared variables task 6 params 0 16 fetch data from point address aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 7 FETCH SINGLE DATA POINT USING POINT LIST Perform a conversion on the point address in the point list indicated by the point list index NOTES 1 Each time a point is fetched from the list the list index is increm
123. s 8 status call the driver if stats 0 printf Error code d returned by the driver status print error code if any 9 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL USE WITH AC REFERENCE Apart from uses as standard DC output D A s these circuits can be used with a variable bipolar AC or DC reference signal In this mode they perform as a digitally programmed gain control or attenuator The voltage output Vout digital input V 4096 A parameter of interest in AC operation is feed through the amount of residual signal at digital zero Feed through is mainly a function of stray capacitance and rises with frequency At 10 KHz it is typically 5 mV peak to peak with a 5V reference The D A s will perform well in synchro to digital and resolver applications which typically occur at 400 HZ The accuracy vs frequency characteristics of the D A s will be less than 12 bits at frequencies above 1 KHZ due to distributed capacitance in the R 2R ladder network of the D A ARBITRARY WAVEFORM OUTPUT A common requirement for D A s in test applications is to output a waveform At low frequencies this can be done with a timing loop in your program but it is difficult to control the timing with any degree of precision when operating at more than a few points per second TASK 18 provides a method to output data from an array using interrupts The maximum rate at which data can be transferred depends mainly on
124. s made AIM 16P AIM 16P FUNCTION AD12 16 16F FUNCTION AD12 16 OONDOABRWD 12 volt power unused Gain selection bit 0 unused Gain selection bit 1 Gain selection bit 2 Address selection bit 0 Address selection bit 1 Address selection bit 2 Address selection bit 3 Common logic ground Channel 15 analog input Digital input 1 set for output 5 V REF Digital input 2 set for output Digital input 3 set for output Digital output 0 Digital output 1 Digital output 2 Digital output 3 Common Logic ground unused Channel 14 analog input unused Channel 13 analog input unused Channel 12 analog input unused Channel 11 analog input unused Channel 10 analog input unused Channel 9 analog input LL GND Analog Common LL GND Analog Common 10 V REF 12 volt power unused Channel 8 analog input unused LL GND Analog Common unused D A channel 0 output unused D A channel 0 reference input unused Digital input 0 A D trigger unused D A channel 1 reference input unused D A channel 1 output 10 V REF return 5 volt power Output channel 7 Output channel 6 Output channel 5 Output channel 4 Output channel 3 Output channel 2 Output channel 1 Output channel 0 5 volt power Channel 7 analog input Channel 6 analog input Channel 5 analog input Channel 4 analog input Channel 3 analog input Channel 2 analog input Channel 1 analog input Channel 0 analog input 10 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F
125. s select the desired interrupt level ea il IRQ LEVEL None disabled None disabled IRQ2 IRQ3 IRQ4 IRQ5 IRQ6 IRQ7 23320000 300 3700 O 0 00 X This bit is a don t care It is good programming practice to set this bit to 0 DMA Direct memory access DMA transfers are enabled when B2 1 and disabled when B2 0 It is your responsibility to set up the DMA controller in the PC and the page registers before enabling DMA on the AD12 16 16F S1 and S0 These bits control the source of start pulses for the A D A D TRIGGER SOURCE Software start only 0 X 1 0 Rising external A D start IPO 1 1 Counter Timer 1 amp 2 output NOTE Regardless of the state of S1 and SO an A D conversion can always be initiated by a write to the Base Address COUNTER TIMER REGISTERS Base 10 Write This two bit write only register controls operation of the Counter Timer The type 8254 counter timer chip used contains three 16 bit counters Counters 1 and 2 are cascaded and driven by a 1 MHz or 10 MHz clock for periodic triggering of the A D Periods of a few microseconds to in excess of an hour can be programmed Counter 0 is uncommitted and provides a gated 16 bit binary counter that can be used for event or pulse counting delayed triggering or in conjunction with other channels for frequency or period measurement 4 6 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL ieee eee CO CO and the External A D Sta
126. se are globally declared variables task 13 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 14 COUNTER TIMER SETUP Load the given counter timer with a count value and mode NOTES 1 When the AD12 16 16F is used with an AIM 16P counter 0 is not available for use 2 For a complete discussion of the counter timers see CHAPTER SEVEN INPUT params 0 counter number 0 1 or 2 params 1 counter mode between 0 and 5 params 2 counter load count OUTPUT DATA None ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 8 Invalid counter not 0 1 or 2 status 9 Invalid counter mode not between 0 and 5 EXAMPLE int task params 7 status these are globally declared variables task 14 params 0 1 counter 1 params 1 3 counter mode 3 square wave generator params 2 100 counter load value acts as divide by 100 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 15 READ COUNTER TIMER COUNT Reads the count of the given counter timer 6 18 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL NOTES 1 For a complete discussion of the counter timers see CHAPTER SEVEN 2 Counter timer is latched before read INPUT params 0 counter number 0 1 or 2 OUTPUT DATA params 1 counter timer count ERROR CODES status 0 No error
127. se discrete inputs IP1 though IP3 are used to control the gain of the AlM 16P Four bits of digital output are available with LSTTL logic levels and 10 LSTTL load drive capability Discrete outputs OPO through OP3 provide multiplexer addressing capability for input expansion card use as described in the INPUT SYSTEM EXPANSION section or as separate digital outputs COUNTER TIMER The AD12 16 16F contain a type 8254 counter timer which has three 16 bit programmable down counters Counter Timer O is enabled by a digital input IP2 and uses either an internal 100 KHz clock or an external clock of up to 10 MHz as selected by user software This counter timer is not committed on the card it s clock enable and output lines are available to you at the I O connector Counter Timers 1 and 2 are concatenated and form a 32 bit counter timer for timed A D trigger pulses and or for external frequency generation The dual counter timer can be enabled by program control and clocked by a jumper selected 1 MHz or 10 MHz on board crystal oscillator source 2 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL Counter Timer 0 and Counter Timers 1 and 2 can be set up for event counting frequency or period measurements and pulse or wave form generation Also Counter Timers 1 and 2 can be programmed to initiate A D conversions See the PROGRAMMABLE INTERVAL TIMER section of this manual for a description of ways that the type 8254 counter timer chip can be us
128. ses params 3 0 do one cycle only a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 6 DO N A D CONVERSIONS USING DMA Perform N conversions using DMA and store the results in a specified segment of memory NOTES 1 DMA is performed purely by the system and the AD12 16 16F is a background 2 4 6 _ operation and is very fast Throughput is limited mostly by the settle time of the Sample Hold amplifier and the A D converter The AD12 16 can provide a maximum of about 60 000 conversions per second The AD12 16F uses a faster A D converter and can sustain a throughput slightly over 100 000 conversions per second The A D will perform conversions on channels according to the scan limits set in either Task O or Task 1 You may not re install the DMA task if the DMA task is still active Error 20 will result If you use the recycle mode which generates continuous DMA then Task 7 which disables DMA must be run before you can successfully run Task 6 again If you are using the non recycle mode then it must have reached the word count which automatically disables DMA or disable the operation with Task 7 before Task 6 can be run again The segment registers are not incremented by the handler therefore the maximum data area available is 64K a page for 32 767 conversions Be sure that your data area is not in use by your program or altered by subsequent
129. simultaneously and thus it is possible that carries will be propagated from the low to the high byte during the read cycle To circumvent these problems you can perform a counter latch operation in advance of the read cycle To do this load the RW1 and RW2 bits with zeroes This instantly latches the count of the selected counter selected via the SC1 and SCO bits in a 16 bit hold register An alternative method of latching counter s which has an additional advantage of operating simultaneously on several counters is by use of a readback command to be discussed later A subsequent read operation on the selected counter returns the held value Latching is the best way to read a counter on the fly without disturbing the counting process You can only rely on directly read counter data if the counting process is suspended while reading by bringing the gate low or by halting the input pulses For each counter you must specify in advance the type of read or write operation that you intend to perform You have a choice of loading reading a the high byte of the count or b the low byte of the count or c the low byte followed by the high byte This last is of the most general use and is selected for each counter by setting the RW1 and RWO bits to ones Of course subsequent read load operations must be performed in pairs in this sequence or the sequencing flip flop in the 8254 chip will get out of step 8 4 ANALOG DIGITAL 1 0 CARD AD12 16 16
130. stalled some local area network interfaces may use this level DMA level 2 is always used by the floppy disk to read write data and cannot be shared with other devices On floppy disk only machines DMA level 3 is free If the PC does have a hard disk depending on the type of hard disk controller used level 3 may be free The hard disk controller contains the fixed disk BIOS Some manufacturers make use of block moves MOVs others use hardware DMA to transfer data between the disk controller and DOS disk buffers in memory This is transparent to the user as the BIOS calls are functionally identical However when you install another peripheral that uses DMA it s useful to know whether or not your controller uses level 3 The AD12 16 16F can be operated on either levels 1 or 3 Since the AD12 16 16F is a relatively slow device in terms of DMA service the higher priority level 1 offers little real performance advantage over level 3 Note also that until a DMA operation is enabled on the AD12 16 16F the DMA request line DREQ from the card is tri stated Therefore you can share it with other devices on the same level as long as they won t be enabled at the same time PAGE REGISTER AND DMA CONTROLLER FUNCTIONS The 8237 DMA controller was designed in the days of eight bit CPU s and 64K memories and it can only handle a 16 bit address AO through A15 Since the 8088 CPU uses a C 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 20 bit
131. starting at the lower limit through the highest channel possible then reset to 0 and scan until the high limit is reached For example if params 0 13 and params 1 2 the sequence would be 13 14 15 0 1 2 13 14 15 0 1 2 13 14 etc If you are using the card in the 8 channel differential mode avoid setting the lower limit greater than the upper limit because the counter will attempt to cycle through channels 8 through 15 If you wish to perform continuous conversions on only one channel set the low and high scan limits equal to each other Control of the multiplexer address is performed by high speed hardware on the AD12 16 16F card and is independent of the processor Approximately two microseconds after the A D has been triggered and the Sample Hold amplifier is holding the previous sample the multiplexer is advanced to the next channel This allows the instrumentation amplifier to settle before the Sample Hold amplifier returns to the sample state at the end of the 12 microsecond A D conversion 8 microseconds on AD12 16F This pipelining technique optimizes throughput of the system 6 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL INPUT params 0 Lower scan limit params 1 Upper scan limit OUTPUT DATA NONE ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 3 Card does not respond status 17 Invalid channel number EXAMPLE int task params
132. status 5 Invalid point address or index status 6 Invalid gain code EXAMPLE int task params 7 status these are globally declared variables task 4 params 0 1 first point address in range params 1 15 last point address in range params 2 3 gain code of 3 aa16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 5 ASSIGN POINT ADDRESSES TO THE POINT LIST Assigns a range of point addresses to the point list NOTES 6 7 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL 1 All point addresses added to the point list are appended to the end of the point list after any that have been previously added including the default point address If you desire to start with an empty list then use TASK 11 to clear the point list first If the first point address is larger than the last point address then the driver will install them in descending order Point addresses that are not on a 16 boundary 0 16 32 48 etc are only meaningful if one or more AIM 16P s are attached 2 oO INPUT params 0 First point address in range params 1 Last point address in range OUTPUT DATA None ERROR CODES status 0 No error status 1 Invalid task number task gt 20 or driver not initialized status 4 Point list error list full status 5 Invalid point address or index EXAMPLE int task params 7 status these are globally declared variable
133. t Digital input 0 A D trigger D A channel 1 reference input D A channel 1 output 5 volt power Channel 15 analog input Channel 14 analog input Channel 13 analog input Channel 12 analog input Channel 11 analog input Channel 10 analog input Channel 9 analog input Channel 8 analog input ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL This page purposely omitted 10 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL SPECIFICATIONS ANALOG INPUTS Channels Switch selectable 8 differential Hi Lo Gnd or 16 single ended Resolution 12 binary bits Accuracy Can be calibrated to 0 01 of reading 1 bit At Gain 1 2 5 10 0 002 typical 0 04 maximum w o recalibration Voltage Range Switch selectable 10V 5V 2 5V 1V 0 5V or 0 10V 0 5V 0 2V 0 1V Coding True binary for unipolar inputs and offset binary for bipolar inputs Overvoltage Continuous single channel to 15V without damage Input Current 1 1 nA maximum 125 pA typical at 25 C Temp Coefficient Gain 50 PPM C at gain 0 5 1 and 10 78 PPM C at gain 2 63 PPM C at gain 5 Zero 27 PPM C maximum at gain 10 107 PPM C maximum at gain 1 A D SPECIFICATION Type Successive approximation Resolution 12 binary bits Conversion Time AD12 16 15 usec max 12 usec typical AD12 16F 9 5 usec max 7 5 usec typical Monotonicity Guaranteed over operating temperature range Linearity 1 bit Zero Drift 10 PPMC maximum G
134. t counting Mode 3 Square Wave Generator This mode operates periodically like mode 2 The output is high for half of the count and low for the other half If the count is even then the output is a symmetrical square wave If the count is odd then the output is high for N 1 2 counts and low for N 1 2 counts Periodic triggering or frequency synthesis are two possible applications forthis mode Note that in this mode to achieve the square wave the counter decrements by two for the total loaded count then reloads and decrements by two for the second part of the wave form Mode 4 Software Triggered Strobe This mode sets the output high and when the count is loaded the counter begins to count down When the counter reaches zero the output will go low for one input period The counter must be reloaded to repeat the cycle A low gate input will inhibit the counter This mode can be used to provide a delayed software trigger for initiating A D conversions Mode 5 Hardware Triggered Strobe In this mode the counter will start counting after the rising edge of the trigger input and will go low for one clock period when the terminal count is reached The counter is retriggerable The output will not go low until the full count after the rising edge of the trigger 8 2 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL PROGRAMMING On the AD12 16 16F the 8254 counters occupy the following addresses Base Address 12 Read Write Cou
135. t of range limits are not in O to 7 range status 7 Single ended scan limits are out of range limits are not in O to 15 range 5 5 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL EXAMPLE int task params 7 status these are globally declared variables task 1 params 0 2 lower scan limit is channel 2 params 1 15 upper scan limit is channel 15 a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 2 FETCH MUX SCAN LIMITS AND CURRENT CHANNEL Determine the current multiplexer channel setting and scan limits NOTES 1 If Task 2 is run during the 8 12 microsecond interval when the A D is busy and the multiplexer address is possibly being incremented the task will wait until the A D has finished converting Thus the multiplexer address returned always corresponds to the next channel to be converted INPUT None RETURNS DATA params 0 Channel address for next conversion O through 15 params 1 Lower scan limit O though 15 params 2 Upper scan limit 0 though 15 ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 EXAMPLE int task params 7 status these are globally declared variables task 2 al6drv FP_OFF Stask FP_OFF params FP_OFF status call the driver 5 6 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 3 PERFORM A SINGLE A D C
136. the best configuration for triggering the A D To change their mode use the direct outportb instructions or your language s equivalent INPUT 5 15 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL params 0 Counter operating mode 0 Pulse on terminal count Output low on trigger goes high on terminal count 1 Programmable one shot Output pulses low for one clock time on terminal count 2 Rate generator or divide by N counter Output pulses low every terminal count 3 Square wave generator Output high for one half of the count and low for the other half 4 Software triggered strobe Output pulses low on terminal count after loading 5 Hardware triggered strobe Output pulses low on terminal count RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 12 Counter mode number out of range 0 to 5 EXAMPLE int task params 7 status these are globally declared variables task 10 params 0 2 set counter 0 to rate generator mode a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver TASK 11 LOAD COUNTER 0 Sets the operating mode of counter 0 NOTES 1 Since the counter is a 16 bit device counts as high as 65 535 are possible In BASIC integer variables are signed 16 bit words i e can have values between 32 767 and 32 767 To load a number large
137. to counter 0 task 10 set counter 0 mode task params 0 3 set counter 0 mode to 3 a16drv FP_OFF task FP_OFF params FP_OFF status call the driver task 11 set counter 0 count task params 0 100 set counter 0 count to 100 al6drv FP_OFF task FP_OFF params FP_OFF status call the driver Counters 1 and 2 will always be set to the rate generator configuration by the A16DRV driver when Task 0 is run But you can use direct register write statements to alter their operating configuration to the square wave configuration The frequency range available is identical to that obtained in the rate generator mode There is considerable flexibility in output frequency range With a division ratio of 2 65 535 x 65 535 a 1MHz clock input results in an output of about 1 pulse hour At the other extreme with a minimum division ratio of 4 2 2 and a 10MHz clock input a 2 5MHz output can be generated 8 9 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL MEASURING FREQUENCY AND PERIOD The two previous sections show how to count pulses and generate output frequencies It is also possible to measure frequency by raising the gate input of Counter 0 for a known time interval and counting the number of clock pulses accumulated for that interval The gating signal can be derived from Counters 1 and 2 operating in a square wave mode Counter 0 can also be used to measure pulse width or half period
138. transfer For example a normal program transfer would entail Clk Periods LOOP IN AX DX read data from I O port 8 MOV DI AX transfer to memory DS DI 10 CMP DI LIMIT end of transfer 4 JZ EXIT yes exit 4 INC DI no continue 2 INC DI increment memory pointer 2 JMP LOOP repeat 15 EXIT continue The total clock periods are 43 which on a 4 77 MHz IBM compatible PC is 9 uS execution time In practice an A D service routine would be more involved because it would require checking the status of the A D to see if the data was ready etc and execution time makes it difficult to handle data conversion rates in excess of 10 KHz even in 4 77 MHz computers Still another serious shortcoming to programmed transfers through the CPU is that they are liable to disruptions from interrupts DMA avoids these problems The A D on the AD12 16 16F is triggered by the programmable interval timer or an external Start pulse performs a conversion and issues two sequential DRQ s at the end of conversion Upon receipt of each DACK the two bytes of data corresponding to the conversion are transferred to the memory location put on the memory address bus by the DMA controller This transfer usually takes place in a few microseconds and is undisturbed by interrupts Since A D data are latched and held until the end of the next conversion there is a maximum of 10 microseconds available A D conversion at maximum sample rate for the transfer to take plac
139. ue binary and left justified Base 4 Write Write DAC 0 least significant byte ez pe B5 es ms ap er so loss or par ovo x x x x J DAO DA3 Least significant four bits of the DAC 0 output value DAO is the least significant bit X These are don t care bits Itis good programming practice to set these bits to 0 Base 5 Write Write DAC 0 most significant byte DA4 DA11 The eight most significant bits of the DAC 0 output DA11 is the most significant bit Base 6 Write Write DAC 1 least significant byte The format is the same as base 4 Base 7 Write Write DAC 1 most significant byte The format is the same as base 5 CARD STATUS AND CLEAR INTERRUPT The Status register provides information about the operation and configuration of the analog input functions of the card Writing to the Status register clears interrupt requests 4 4 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL and provides means of acknowledging an AD12 16 16F interrupt and re enabling it Base 8 Read Read the card status B7 B6 B5 B4 B3 B2 B1 BO EOC End of conversion If EOC 1 an A D conversion is underway If EOC is 0 then the A D data registers contain valid data from the previous conversion and the A D is ready to perform the next conversion U B Unipolar Bipolar If the unit is operating in unipolar mode this bit will be a 1 or if operating in bipolar mode the bit will be a 0 MUX Single Ended
140. unters 1 and 2 using Task 17 params 3 Cycle Recycle operation 0 One cycle After completion of the number of conversions specified DMA is disabled and operation status is set to zero 1 Re cycle Data are continuously written to the same memory params 0 corresponds to the memory buffer length Operation will continue until stopped by Task 7 RETURNS DATA The data is stored in the segment address passed starting at offset 0 The data may be converted and placed in an array by using task 9 ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 11 Number of conversions is O or negative status 19 Trigger code not 0 or 1 status 20 Interrupt or DMA already active status 21 Segment page wrap around error status 26 Invalid memory segment status 27 Recycle code not 0 or 1 EXAMPLE int task params 7 status these are globally declared variables task 6 params 0 100 number of conversions params 1 0x5000 use segment 5000 should not be used params 2 1 use timers for conversion pulses params 3 0 do one cycle only a16drv FP_OFF amp task FP_OFF params FP_OFF amp status call the driver 5 12 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 7 TERMINATE DMA INTERRUPT OPERATION Terminates any running interrupt or DMA operation initiated by tasks 5 6
141. vely if params 2 1 negative slope then triggering will occur whenever the triggering signal drops below 2 5V 2 oO 4 x INPUT params 0 A D channel number 0 to 7 in differential mode O to 15 if single ended params 1 Trigger level 0 to 4095 if unipolar 2048 to 2047 if bipolar params 2 slope O positive 1 negative RETURNS DATA None ERROR CODES status 0 No error status 1 Driver has not been initialized with task 0 status 2 Invalid task number task gt 20 status 23 Trigger channel out of range not between 0 and 7 if differential mode or between 0 and 15 if single ended mode status 24 Trigger level out of range not between 0 and 4095 if unipolar or between 2048 and 2047 if bipolar status 25 Slope not 0 or 1 EXAMPLE int task params 7 status these are globally declared variables task 19 params 0 1 use A D channel 1 params 1 1024 set trigger level to 1 4 scale unipolar params 2 0 positive slope at6drv FP_OFF 8task FP_OFF params FP_OFF 8status call the driver 5 24 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL TASK 20 A D CHANNEL SCAN ON INTERRUPT Scans all A D channels set by task 1 upon interrupt trigger NOTES 1 Y 2 This task operates similarly to Task 5 except that instead of performing a single A D conversion on each trigger pulse a complete scan of the channels specified
142. will yield 1st Read Status byte 2nd Read Low byte of latched data 3rd Read High byte of latched data After any latching operation of a counter the contents of its hold register must be read before any subsequent latches of that counter will have any effect If a status latch command is issued before the hold register is read then the first read will read the status not the latched value 8 5 ANALOG DIGITAL 1 0 CARD AD12 16 16F USER MANUAL PROGRAMMING EXAMPLES Generating a Square Wave Output To program Counters 1 and 2 for either a 1 KHz or 10 KHz output depending on setting of the CLOCK jumper you need to divide the 1 or 10MHz crystal oscillator input by 1 000 To obtain a symmetrical waveform the divisor loaded into the counter should be an even number If it is an odd number then one half of the waveform would be one input clock pulse period longer than the other A convenient divisor to use in counter 1 is 10 and counter 2 is 100 because 10 x 100 1 000 outportb BASEADDRESS 15 0x76 counter 1 to square wave mode outportb BASEADDRESS 15 0xb6 counter 2 to square wave mode outportb BASEADDRESS 13 10 write lower byte counter 1 outportt BASEADDRESS 13 0 write upper byte counter 1 outportb BASEADDRESS 14 100 write lower byte counter 2 outporto BASEADDRESS 14 0 write upper byte counter 2 Determining Status of Counter 1 outportb BASEADDRESS 15 Ox

ANALOG AND DIGITAL I/O CARD AD12

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