USB-1208LS User`s Guide
Contents
1. 0x1800 Read write User data area Ox1F00 OxIFEF Read write Calibration data Ox1FFO Ox1FFF Read write System data Power Table 11 Power specifications Parameter Conditions Specification Supply current Note 5 20 mA 5V USB power available Note 6 4 5 V min 5 25 V max 4 1 V min 5 25 V max Connected to self powered hub Connected to bus powered hub Output current Note 7 450 mA min 500 mA max 50 mA min 100 mA max Connected to bus powered hub Connected to bus powered hub Note 5 This is the total current requirement for the USB 1208LS which includes up to 5 mA for the status LED Note 6 Self powered refers to USB hubs and hosts with a power supply Bus powered refers to USB hubs and hosts without their own power supply Note 7 This refers to the total amount of current that can be sourced from the USB 5 analog outputs and digital outputs General Table 12 General specifications Parameter Conditions Specification USB controller clock error 29 C 30 ppm max 0 C to 70 C 50 ppm max Device type Device compatibility USB 1 1 low speed USB 1 1 USB 2 0 Environmental Table 13 Environmental specifications Parameter Specification Operating temperature range Storage temperature range 0 C to 70 C 40 C to 70 C Humidity 0 to 90 non condensing 21 US2. Ideal gt Ideal 9 77 mV 20 mV gt Figure 12 Error band plot 16 USB 1208LS User s Guide Functional Details Mechanical drawings 2 80 00007 0000000009 0000 uuu ERE EO A 10901 000000000000000 028 Figure 13 Circuit board top and enclosure dimensions 17 Chapter 3 Specifications All specifications are subject to change without notice Typical for 25 C unless otherwise specified Specifications in italic text are guaranteed by design Analog input Table 1 Analog input specifications Parameter Conditions Specification A D converter type Successive approximation type Input voltage range for linear operation CHx to GND 10 V max single ended mode Input common mode voltage range for linear CHx to GND 10 V min 20 V max operation differential mode Absolute maximum input voltage CHx to GND 40V max Input current Note 1 Vin 10V 70 uA typ Vin 0V 12 uA typ Vin 10V 94 uA typ Input impedance 122 Number of channels 8 single ended 4 differential software selectable Input ranges Single ended mode 10V G2 Differential mode 20V 10V G G 5 G G G 4 2 5 2 0V 10 1 25 G 16 1 0 20 Software selectable t Throughput Software paced 50 S s Hardware paced 1 2 kS s BURSTIO to 4 K sample FIFO 8 kS s Channel gain queue Up to
3. 8 elements Software configurable channel range and gain Resolution Note 2 Differential 12 bits no missing codes Single ended 11 bits CAL accuracy CAL 2 5V 0 05 typ 0 25 max Integral linearity error 1 LSB typ Differential linearity error 0 5 LSB typ Repeatability 1 LSB typ CAL current Source 5 mA max Sink 20 pA min 200 nA typ Trigger Source Software selectable External digital TRIG_IN Note 1 Input current is a function of applied voltage on the analog input channels For a given input voltage Vin the input leakage is approximately equal to 8 181 Vin 12 pA Note 2 The AD7870 converter only returns 11 bits 0 to 2 047 codes in single ended mode 18 USB 1208LS User s Guide Specifications Table 2 Accuracy differential mode Range Accuracy LSB 20 V 5 1 10 V 6 1 5 V 8 1 4 V 9 1 42 5 V 12 1 2 V 14 1 1 25 V 20 1 24 1 Table 3 Accuracy single ended mode Range Accuracy LSB 10 V 4 0 Table 4 Accuracy components differential mode all values are Range of Reading Gain Error at FS Offset mV Accuracy at FS mV mV 20 V 0 2 40 9 766 49 766 10 V 0 2 20 9 766 29 766 5 V 0 2 10 9 766 19 766 4 V 0 2 8 9 766 17 766 2 5 V 0 2 5 9 766 14 766 2 V 0 2 4 9 766 13 766 1 25 V 0 2 2 5 9 766 12
4. A channel1 1 22 2 Al channel 1 PortAchannelO 21 1 Al channel 0 Figure 4 Single ended mode pinout Signal connections Analog inputs You can connect up to eight analog input connections to the screw terminal containing pins 1 to 20 CHO IN through CH7 IN You can configure the analog input channels as eight single ended channels or four differential channels When configured for differential mode each analog input has 12 bit resolution When configured for single ended mode each analog input has 1 1 61 resolution due to restrictions imposed by the A D converter Single ended configuration When configured for single ended input mode eight analog channels are available The input signal is referenced to signal ground GND and delivered through two wires Connect the wire carrying the signal to be measured to CH IN Connect the second wire to GND The input range for single ended mode is 10V To perform a single ended measurement using differential channels connect the signal to the CH IN HI input and ground the associated CH IN LO input Differential configuration When configured for differential input mode four analog channels are available In differential mode the input signal is measured with respect to the low input and delivered through three wires Connect the wire carrying the signal to be measured to CH IN Connect the wir
5. a measurement system Offset gain nonlinearity The primary error sources in the USB 1208LS are offset and gain Nonlinearity is small in the USB 1208LS and is not significant as an error source with respect to offset and gain Figure 9 shows an ideal error free USB 1208LS transfer function The typical calibrated accuracy of the USB 1208LS is range dependent as explained in the Specifications chapter We use a 10 V range here as an example of what you can expect when performing a measurement in this range Input Voltage Output Code N 2048 4095 Figure 9 Ideal ADC transfer function The USB 1208LS offset error is measured at mid scale Ideally a zero volt input should produce an output code of 2048 Any deviation from this is an offset error Figure 10 shows the USB 1208LS transfer function with an offset error The typical offset error specification on the 10 V range is 9 77 mV Offset error affects all codes equally by shifting the entire transfer function up or down along the input voltage axis 14 USB 1208LS User s Guide Functional Details The accuracy plots in Figure 10 are drawn for clarity and are not drawn to scale Input Voltage Ideal Offset 9 77 mV Output Code 72048 9 77 mV 4095 Actual E Figure 10 ADC transfer function with offset error Gain error is a change in the slope of the transfer function from the ideal and is typically ex
6. channel 4 4 25 Port A channel 3 PortA3 24 Port A channel 2 PortA2 23 Port A channel 1 PortA1 22 Port A channel 0 Port 21 CH21NLO Al channel 2 CH2 IN HI Al channel 2 GND Ground CH11INLO channel 1 CH1 IN HI Al channel 1 GND Ground CHO IN LO Al channel 0 CHO IN HI Al channel 0 oooooooooooooooooooQ 5 oooooooooooooooooooQ NO RO Oo Figure 3 Differential mode pinout USB 1208LS User s Guide Functional Details The single ended mode pinout is shown in Figure 4 Ground GND 40 O 20 CTR Counter input Port channel7 PortB7 39 O 19 GND Ground Port B channel 6 38 O 18 TRIG IN Trigger input PortBchannel5 5 37 O 17 GND Ground Port B channel4 4 36 16 CAL Calibration Port B PortB3 35 15 GND Ground Port channel 2 PortB2 34 14 D AOUT1 AOchannel1 Port B channel 1 33 O 13 D AOUTO AOchannelO Port B channel O PortBO 32 O 12 GND Ground Ground GND 31 O 11 CH7IN Al channel 7 Power output 5V 30 O 10 CH6IN Al channel 6 Ground GND 29 6 9 GND Ground Port A channel7 7 28 O G8 CH5IN Al channel 5 Port A channel6 PortA6 27 O O 7 Al channel 4 Port channel5 Port A5 26 O G6 GND Ground Port A channel4 Port A4 25 O 95 CH3IN Al channel 3 Port A channel3 PortA3 24 O G4 21 Al channel 2 Port A channel2 Port A2 23 O GND Ground Port
7. high voltage 2 5 mA Output low voltage IOL 2 5 mA 3 0 V min 0 4 V max External trigger Table 8 Trigger input specifications Parameter Conditions Specification Trigger source Note 4 External digital TRIG IN Trigger mode Software selectable Level sensitive user configurable for TTL level high or low input Trigger latency Burst 25 us min 50 us max Trigger pulse width Burst 40 us min Input high voltage 3 0 V min 15 0 V absolute max Input low voltage 0 8 V max Input leakage current 1 0 uA Note 4 TRIG IN is protected with a 1 5 kQ series resistor Counter Table 9 Counter specifications Parameter Specification Counter type Event counter Number of channels 1 Input source CTR screw terminal Input type TTL rising edge triggered Resolution 32 bits Schmidt trigger hysteresis 20 mV to 100 mV Input leakage current tl uA Maximum input frequency 1 MBz High pulse width 500 ns min Low pulse width 500 ns min Input low voltage 0 V min 1 0 V max Input high voltage 4 0 V min 15 0 V max 20 USB 1208LS User s Guide Specifications Non volatile memory Table 10 Memory specifications Parameter Memory size Memory configuration Specification 8192 bytes Address Range Access Description 0x0000 Ox17FF Read write A D data 4K samples
8. is being transferred Blinks three times Initial communication is established between the USB 1208LS and the computer Blinks at a slow rate The analog input is configured for external trigger The LED stops blinking and lights steady green when the trigger is received Screw terminal wiring The screw terminals provide the following connections Eight analog inputs CHO IN to CH7 IN Two analog outputs D A OUT 0 to D A OUT 1 16 digital I O connections PortAO to Port A7 and Port BO to Port B7 External trigger input TRIG_IN External event counter input CTR Power output PC 5 V Calibration output CAL Ground connections GND Use 16 AWG to 30 AWG wire when making connections to the screw terminals The differential mode pinout is shown in Figure 3 Ground GND 40 20 CTR Counter input Port B channel 7 PortB7 39 19 GND Ground Port B channel6 38 18 TRIG IN Trigger input Port B channel 5 Port B5 37 17 GND Ground Port B channel 4 Port B4 36 16 CAL Calibration Port B channel 3 Port 35 15 Ground Port B channel 2 B2 34 Port B channel 1 Port B1 33 A D A OUT 1 AO channel 1 D A OUTO AOchannel 0 wo Port B channel 0 Port BO 32 12 GND Ground Ground GND 31 11 CHSINLO Alchannel 3 Power output 5V 30 CHS IN HI Al channel 3 Ground GND 29 9 Ground Port A channel 7 PortA7 28 Port A channel 6 Port A6 27 Port A channel 5 Port A5 26 Port A
9. the device run Windows Update to update your system with the latest HID and USB drivers To connect the USB 1208LS to your system turn your computer on and connect the USB cable to a USB port on your computer or to an external USB hub that is connected to your computer The USB cable provides power and communication to the device When you connect the USB 1208LS for the first time a Found New Hardware dialog opens when the operating system detects the device Another dialog identifies the USB 1208LS as a USB Human Interface Device When this dialog closes the installation is complete The device LED should blink and then remain on to indicate that communication is established between the device and your computer If the LED turns off If the LED is on but then turns off the computer has lost communication with the USB 1208LS To restore communication disconnect the USB cable from the computer and then reconnect it This should restore communication and the LED should turn back on Calibrating the hardware Field calibration The USB 1208LS supports field calibration Calibrate the device using InstaCal whenever the ambient temperature changes by more than 10 C from the last calibration Factory calibration The Measurement Computing Manufacturing Test department performs the initial factory calibration Contact Measurement Computing for details about how to return your device and have it calibrated to the factory spec
10. 0 mA ea 120 mA For an application running on a PC or powered hub the maximum available excess current is 500 mA 120 mA 380 mA This number is the total maximum available current at the PC 5V screw terminals Cole Parmer highly recommends that you figure in a safety factor of 2096 below this maximum current loading for your applications A conservative safe user maximum in this case would be in the 300 320 mA range Since laptop computers typically allow up to 100 mA the USB 1208LS in a fully loaded configuration may be above that allowed by the computer In this case you must determine the per pin loading in the application to ensure that the maximum loading criteria is met The per pin loading is calculated by simply dividing the 5 V by the load impedance of the pin in question Ground terminals The GND connections are identical and provide a common ground for all device functions 13 USB 1208LS User s Guide Functional Details Accuracy The overall accuracy of any instrument is limited by the error components within the system Quite often resolution is incorrectly used to quantify the performance of a measurement product While 12 bits or 1 part in 4096 does indicate what can be resolved it provides little insight into the quality of an absolute measurement Accuracy specifications describe the actual results that can be realized with a measurement device There are three types of errors which affect the accuracy of
11. 15 GND 35 Port 16 CAL 36 Port B4 17 GND 37 Port 5 18 TRIG_IN 38 Port B6 19 GND 39 Port B7 20 CTR 40 GND 23 Declaration of Conformity Manufacturer Measurement Computing Corporation Address 10 Commerce Way Suite 1008 Norton MA 02766 USA Category Electrical equipment for measurement control and laboratory use Measurement Computing Corporation declares under sole responsibility that the product USB 1208LS to which this declaration relates is in conformity with the relevant provisions of the following standards or other documents EC EMC Directive 2004 108 EC General Requirements EN 61326 1 2006 IEC 61326 1 2005 Emissions EN 55011 2007 CISPR 11 2003 Radiated emissions Group 1 Class A EN 55011 2007 CISPR 11 2003 Conducted emissions Group 1 Class A Immunity EN 61326 1 2006 Table 3 IEC 61000 4 2 2001 Electrostatic Discharge immunity IEC 61000 4 3 2002 Radiated Electromagnetic Field immunity To maintain compliance to the standards of this declaration the following conditions must be met The host computer peripheral equipment power sources and expansion hardware must be CE compliant All I O cables must be shielded with the shields connected to ground I O cables must be less than 3 meters 9 75 feet in length The host computer must be properly grounded Equipment must be operated in a controlled electromagnetic environment as defined by Standar
12. 20V 10 V 10V 0V 20 V 20V 10 V 10V 20 V 10 V 10 V 15 V 5 V 20 V 20 V 0 20 V For more information on analog signal connections For more information on single ended and differential inputs refer to the Guide to DAQ Signal Connections this document is available on our web site at www mccdaq com signals signals pdf Channel Gain queue The channel gain queue feature allows you to set up a scan sequence with a unique per channel gain setting and channel sequence The gain settings are stored in a channel gain queue list that is written to local memory on the device The channel gain queue list can contain up to 8 elements in any order An example of a four element list is shown in the table below Sample channel gain queue list Element Channel Range 0 CHO BIP10V 1 BIPSV 2 CH3 BIP10V 3 CH2 When scan begins with the gain queue enabled the USB 1208LS reads the first element sets the appropriate channel number and range and then acquires a sample The properties of the next element are then retrieved and another sample is acquired This sequence continues until all elements in the gain queue have been selected When the end of the channel list is detected the sequence returns to the first element in the list This sequence repeats until the specified number of samples is acquired Carefully match the gain to the expected voltage range on the associ
13. 266 1 0 2 2 9 766 11 766 Table 5 Accuracy components single ended mode all values Range 96 of Reading Gain ErroratFS Offset mV Accuracy at FS mV mV 10 V 0 2 20 19 531 39 531 Analog output Table 6 Analog output specifications Parameter Conditions Specification D A converter type PWM Resolution 10 bits 1 in 1024 Maximum output range 0Vto5V Number of channels 2 Throughput Software paced 100 S s single channel mode 50 S s dual channel mode Power on and reset voltage Initializes to 000h code Maximum voltage Note 3 No load Vs mA load 0 99 Vs 5 mA load 0 98 Vs Output current drive Each D A OUT 30 mA Slew rate 0 14 V ms typ Note 3 Vs is the USB bus 5 power The maximum analog output voltage is equal to Vs at no load V is system dependent and may be less than 5 volts 19 USB 1208LS User s Guide Specifications Digital input output Table 7 DIO specifications Parameter Specification Digital type 82C55 Number of I O 16 Port AO through A7 Port BO through B7 Configuration 2 banks of 8 Pull up pull down configuration All pins pulled up to Vs through 47 kQ resistors default Positions available for pull down to ground Hardware selectable through 0 Q resistors as a factory option Input high voltage 2 0 V min 5 5 V absolute max Input low voltage 0 8 V max 0 5 V absolute min Output
14. B 1208LS User s Guide Specifications Mechanical Table 14 Mechanical specifications Parameter Specification Dimensions W x 79 x 82 x 27 mm 3 10 3 20 x 1 05 in USB cable length 3 m 9 84 ft max User connection length 3 m 9 84 ft max Signal connector Parameter Specification Connector type Screw terminal Wire gauge range 16 AWG to 30 AWG 4 channel differential mode pinout Pin Signal Name Pin Signal Name 1 CHO IN HI 21 Port AO 2 CHO IN LO 22 Port 1 3 GND 23 Port A2 4 CH1 IN HI 24 Port A3 5 CH1 IN LO 25 Port A4 6 GND 26 Port A5 7 CH2 IN HI 27 Port A6 8 CH2 IN LO 28 Port A7 9 GND 29 GND 10 CH3 IN HI 30 PC 5V 11 CH3 IN LO 31 GND 12 GND 32 Port BO 13 D A OUT 0 33 Port B1 14 D A OUT 1 34 Port B2 15 GND 35 Port 16 CAL 36 Port B4 17 GND 37 Port 5 18 TRIG_IN 38 Port B6 19 GND 39 Port B7 20 CTR 40 GND 22 USB 1208LS User s Guide Specifications 8 channel single ended mode Pin Signal Name Pin Signal Name 1 CHO IN 21 2 CH1 IN 22 Port A1 3 GND 23 Port A2 4 CH2 IN 24 Port A3 5 CH3 IN 25 Port A4 6 GND 26 Port A5 7 CH4 IN 27 Port A6 8 CH5 IN 28 Port A7 9 GND 29 GND 10 CH6 IN 30 PC 5V 11 CH7 IN 31 GND 12 GND 32 Port BO 13 D A OUT 0 33 Port B1 14 D A OUT 1 34 Port B2
15. N hee Chapter 2 Installing the USB 1208LS EE Installing the software Installing the hardware este ee WERTE Calibrating the hardware scd eee i dece eee deer Hecate A THREE Ra Field calibrato ze eR e e RERO e Toe bo ER Veo E ede orte ERI Factory calibration CEP Chapter 3 Functional Details iunii aaar E aaan A ceed dec deccdadetenadasudecasuiedecsseedeuedae Analog imputacquisitlon Todes EO ob reden Software Paced Mode i inr cte eb guts Moos da o e erede desea docte Spese p rede Lo Ue ra ore ae De FU Hee dod Hardware paced nodes 3 110 hace BURSITIO mode nen ena eene ER UD PEDI ER eoi External components nei eee ridet ie de eie DG ree e Ue eed ONE YE WS eno e tiri e eR P reed Signal connectiols d dee eut ee EE Ue e ar REIR EE d 10 Analog A dede ib em de ehe ede d e o et foe iad RE E E oia Counter input Calibration output PO Wels OULU E M io TMM Ee E Ground terminals ACCAC Yi se via weet eee Mechanical drawi
16. USB 1208LS Analog and Digital I O User s Guide Document Revision 4 June 2015 MEASUREMENT Copyright 2015 4W 449 COMPUTING Your new Measurement Computing product comes with a fantastic extra Management committed to your satisfaction Thank you for choosing a Measurement Computing product and congratulations You own the finest and you can now enjoy the protection of the most comprehensive warranties and unmatched phone tech support It s the embodiment of our mission To provide data acquisition hardware and software that will save time and save money Simple installations minimize the time between setting up your system and actually making measurements We offer quick and simple access to outstanding live FREE technical support to help integrate MCC products into a DAQ system Limited Lifetime Warranty Most MCC products are covered by a limited lifetime warranty against defects in materials or workmanship for the life of the product to the original purchaser unless otherwise noted Any products found to be defective in material or workmanship will be repaired replaced with same or similar device or refunded at MCC s discretion For specific information please refer to the terms and conditions of sale Harsh Environment Program Any Measurement Computing product that is damaged due to misuse or any reason may be eligible for replacement with the same or similar device for 50 of the current list p
17. acity of the USB 1208LS 4 k sample FIFO You can initiate a single acquisition sequence of up to 4096 samples channels by either a software command or an external hardware trigger Captured data is read from the FIFO and transferred to a user buffer in the host PC BURSTIO scans are limited to the depth of the on board memory as the data is acquired at a rate faster than it can be transferred to the computer The maximum sampling rate is an aggregate rate The maximum rates that you can acquire data using burst scan mode is 8 kS s divided by the number of channels in the scan External components The USB 1208LS external components are shown in Figure 2 1 Screw terminal pins 211040 3 Screw terminal pins 1 to 20 2 LED 4 USB connector Figure 2 USB 1208LS external components USB 1208LS User s Guide Functional Details USB connector The USB connector is on the right side of the USB 1208LS housing This connector provides 5V power and communication The voltage supplied through the USB connector is system dependent and may be less than 5V No external power supply is required LED The LED on the front of the housing indicates the communication status of the USB 1208LS It uses up to 5 mA of current and cannot be disabled The table below defines the function of the LED LED illumination LED state Indication On steady green The USB 1208LS is connected to a computer or external USB hub Blinks continuously Data
18. ase Where to find more information Additional information about USB 1208LS hardware is available on our website at www mccdaq com You can also contact Measurement Computing Corporation with specific questions Knowledgebase kb mccdaq com Tech support form www mccdaq com support support form aspx Email techsupport mccdaq com Phone 508 946 5100 and follow the instructions for reaching Tech Support For international customers contact your local distributor Refer to the International Distributors section on our website at www mccdaq com International Chapter 1 Introducing the USB 1208LS The USB 1208LS features eight analog inputs two 10 bit analog outputs 16 digital I O connections and one 32 bit external event counter The analog inputs are software configurable for either eight 11 bit single ended inputs or four 12 bit differential inputs An on board industry standard 82C55 programmable peripheral interface chip provides the 16 digital I O lines in two 8 bit ports You can configure each port independently for either input or output The USB 1208LS is powered by the 5 volt USB supply from your computer no external power is required T O connections are made to the device screw terminals The USB 1208LS device is compatible with both USB 1 1 and USB 2 0 ports The speed of the device may be limited when using a USB 1 1 port due to the difference in transfer rates on the USB 1 1 versions of the pro
19. ated channel or an over range condition may occur Although this condition does not damage the device it does produce a useless full scale reading and can introduce a long recovery time due to saturation of the input channel Digital I O You can connect up to 16 digital I O lines to the screw terminal containing pins 21 to 40 Port AO to Port A7 and Port BO to Port B7 You can configure each digital port for either input or output When you configure the digital bits for input you can use the digital I O terminals to detect the state of any TTL level input 12 USB 1208LS User s Guide Functional Details Refer to the schematic shown in Figure 8 If the switch is set to the 5 V input Port AO reads TRUE 1 If you move the switch to GND Port 0 reads FALSE Port AO 1 1 5V GND Figure 8 Schematic showing switch detection by digital channel Port AO For more information on digital signal connections For more information on digital signal connections and digital I O techniques refer to the Guide to DAQ Signal Connections available on our web site at www mccdag com signals signals pdf Trigger input The TRIG_IN terminal is an external digital input that you can configure for either TTL level high or low Counter input The CTR terminal is a 32 bit event counter that can accept frequency inputs up to 1 MHz The internal counter increments when the TTL levels transition from low to high Calib
20. ds EN 61326 1 2006 or IEC 61326 1 2005 Declaration of Conformity based on tests conducted by Chomerics Test Services Woburn MA 01801 USA in May 2004 Test records are outlined in Chomerics Test Report EMI3876 04 Further testing was conducted by Chomerics Test Services Woburn MA 01801 USA in December 2008 Test records are outlined in Chomerics Test report EMI5215B 08 We hereby declare that the equipment specified conforms to the above Directives and Standards R ore Carl Haapaoja Director of Quality Assurance Measurement Computing Corporation 10 Commerce Way Suite 1008 Norton Massachusetts 02766 508 946 5100 Fax 508 946 9500 E mail info mccdag com www mccdag com
21. e carrying the reference signal to CH IN LO Connect the third wire to GND A low noise precision programmable gain amplifier PGA is available on differential channels to provide gains of up to 20 and a dynamic range of up to 12 bits Differential mode input voltage ranges are 20 V 10 V 5 V 4 V 2 5 V 2 0 V 1 25 V and 1 0 V 10 USB 1208LS User s Guide Functional Details In differential mode the following two requirements must be met for linear operation Any analog input must remain in the 10 to 20V range with respect to ground at all times The maximum differential voltage on any given analog input pair must remain within the selected voltage range The input common mode voltage signal of the differential channel must be in the 10 V to 20 V range in order to yield a useful result For example you input a 4 V pp sine wave to CHHI and apply the same sine wave 180 out of phase to CHLO The common mode voltage is 0 V The differential input voltage swings from 4V 4V 8 V to 4 V 4 V 8V Both inputs satisfy the 10 V to 20 V input range requirement and the differential voltage is suited for the 10 V input range see Figure 5 4V Measured Signal CHHI oy N 8V Differential 8V 4V CHLO 4 Figure 5 Differential voltage example common mode voltage of 0 V If you increase the common mode voltage to 11 V the differential remains a
22. ifications Chapter 2 Functional Details Analog input acquisition modes The USB 1208LS can acquire analog input data in three different modes software paced hardware paced and BURSTIO Software paced mode You acquire one analog sample at a time in software paced mode You initiate the A D conversion by calling a software command The analog value is converted to digital and returned to the computer You can repeat this procedure until you have the total number of samples that you want from one channel Software pacing is limited by the 20 mS round trip requirement of a USB interrupt type endpoint operation The maximum throughput sample rate in software paced mode is 50 S s Hardware paced mode You acquire data from up to eight channels in continuous scan mode The analog data is continuously acquired converted to digital values and written to an on board FIFO buffer until you stop the scan The FIFO buffer is serviced in blocks as the data is transferred from the USB 1208LS to the memory buffer on your computer The maximum continuous scan rate of 1 2 kS s is an aggregate rate The total acquisition rate for all channels cannot exceed 1 2 kS s You can acquire data from one channel at 1 2 kS s two channels at 600 S s and four channels at 300 S s You can start a continuous scan with either a software command or with an external hardware trigger event BURSTIO mode In BURSTIO mode you acquire data using the full cap
23. ngs eau evo eee ie Ee n deed 17 Chapter 4 5 e 18 Analog input ne ee RE n e IR RN UI e E RU CREE 18 Analog output e ee ee e eee e tie e i ee ee eer 19 Digital input output x RE e I RR RO ORBI s 20 External trig cer tee REN IRURE TIER 20 die NER Dep ce DRE ORE 20 Non volatile memory RR UU Or QU eO nin ardt n tenet 21 M MD EMO E RR RM 21 General RR NE ERES RE RENE 21 Environmental x ertet AN tiende A RU Reet 21 Mechanical iss HS RD ERI ERE 22 Signal connector eee ee ete ee a ERR AR 22 USB 1208LS User s Guide Declaration of Conformity Preface About this User s Guide This user s guide describes the Measurement Computing USB 1208LS data acquisition device and lists device specifications Conventions in this user s guide For more information Text presented in a box signifies additional information related to the subject matter Caution Shaded caution statements present information to help you avoid injuring yourself and others damaging your hardware or losing your data bold text Bold text is used for the names of objects on a screen such as buttons text boxes and check boxes italic text Italic text is used for the names of manuals and help topic titles and to emphasize a word or phr
24. pressed as a percentage of full scale Figure 11 shows the USB 1208LS transfer function with gain error Gain error is easily converted to voltage by multiplying the full scale FS input by the error The accuracy plots in Figure 11 are drawn for clarity and are not drawn to scale Input Voltage Gain error 0 2 or 20 mV Gain error 0 2 or 20 mV j Actual FS Ideal Output Code 4095 Figure 11 ADC Transfer function with gain error For example the USB 1208LS exhibits a typical calibrated gain error of 0 2 on all ranges For the 10 V range this would yield 10 V x 0 002 20 mV This means that at full scale neglecting the effect of offset for the moment the measurement would be within 20 mV of the actual value Note that gain error is expressed as a ratio Values near FS are more affected from an absolute voltage standpoint than are values near mid scale which see little or no voltage error 15 USB 1208LS User s Guide Functional Details Combining these two error sources in Figure 12 we have a plot of the error band of the USB 1208LS for the 10 V range This is a graphical version of the typical accuracy specification of the product The accuracy plots in Figure 12 are drawn for clarity and are not drawn to scale Input Voltage 4 10 9 77 mV 20 mV Ideal Ideal 9 77 mV 20 mV Output Code Ideal 9 77 mV 20 mV
25. puting Corporation rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form by any means electronic mechanical by photocopying recording or otherwise without the prior written permission of Measurement Computing Corporation Notice Measurement Computing Corporation does not authorize any Measurement Computing Corporation product for use in life support systems and or devices without prior written consent from Measurement Computing Corporation Life support devices systems are devices or systems that a are intended for surgical implantation into the body or b support or sustain life and whose failure to perform can be reasonably expected to result in injury Measurement Computing Corporation products are not designed with the components required and are not subject to the testing required to ensure a level of reliability suitable for the treatment and diagnosis of people HM USB 1208LS 2 Table of Contents Preface About this User s Guide ccccccccccesececcscsssseeseeueeenessneesesueuseanaasusesesueneeanaasseeseeuauauansasesesuanauagaaseeeseensens Conventions inthis ser s gulde RE RATHER SEHR center ene Where to tind more mformatloni to Rede os edd e Re diede Chapter 1 Introducing the USB 1208LS niet utter ettet herue crssesseunnestenes Functional block diagram un eS NER R
26. ration output The CAL terminal is an output used only to calibrate the device Calibration is software controlled via InstaCal Power output The PC 5V terminal is a 5 volt output that is supplied by the computer You can use this terminal to supply power to external devices or circuitry Caution The PC 5V terminal is an output Do not connect to an external power supply or you may damage the USB 1208LS and possibly the computer The maximum total output current that can be drawn from all USB 1208LS connections power analog and digital outputs is 500 mA This maximum applies to most personal computers and self powered USB hubs Bus powered hubs and notebook computers may limit the maximum available output current to 100 mA Just connecting the USB 1208LS to your computer draws 20 mA of current from the USB 5 V supply Once you start running applications each DIO bit can draw up to 2 5 mA and each analog output can draw 30 mA The maximum amount of 5 V current available for experimental use over and above that required by the device 15 the difference between the total current requirement of the USB device based on the application and the allowed current draw of the PC platform 500 mA for desktop PCs and self powered hubs 100 mA for bus powered hubs and notebook computers With all outputs at their maximum output current the total current requirement of the USB 5 V is USB 1208LS 20 mA 16 DIO 2 5 mA ea 2 AO 3
27. rice I O boards face some harsh environments some harsher than the boards are designed to withstand Contact MCC to determine your product s eligibility for this program 30 Day Money Back Guarantee Any Measurement Computing Corporation product may be returned within 30 days of purchase for a full refund of the price paid for the product being returned If you are not satisfied or chose the wrong product by mistake you do not have to keep it These warranties are in lieu of all other warranties expressed or implied including any implied warranty of merchantability or fitness for a particular application The remedies provided herein are the buyer s sole and exclusive remedies Neither Measurement Computing Corporation nor its employees shall be liable for any direct or indirect special incidental or consequential damage arising from the use of its products even if Measurement Computing Corporation has been notified in advance of the possibility of such damages Trademark and Copyright Information Measurement Computing Corporation InstaCal Universal Library and the Measurement Computing logo are either trademarks or registered trademarks of Measurement Computing Corporation Refer to the Copyrights amp Trademarks section on mecdaq com legal for more information about Measurement Computing trademarks Other product and company names mentioned herein are trademarks or trade names of their respective companies 2015 Measurement Com
28. t 8 V Although the common mode voltage signal on each input now has a range of 7 V to 15 V both inputs still satisfy the 10 V to 20 V input requirement see Figure 6 15V Measured Signal 11 8V Differential 8V CHLO 11V 7V Figure 6 Differential voltage example common mode voltage of 11V If you decrease the common mode voltage to 7 V the differential stays at 8 V However the solution now violates the input range condition of 10 V to 20 V The voltage on each analog input now swings from 3V to 11V Voltages between 10 V and 3 V are resolved but those below 10 V are clipped see Figure 7 3V Measured Signal CHHI _7y 11V 8V Differential 7V 3V 7V 11V Figure 7 Differential voltage example common mode voltage of 7 V 11 USB 1208LS User s Guide Functional Details Since the analog inputs are restricted to a 10 V to 20 V signal swing with respect to ground all ranges except 20V can realize a linear output for any differential signal with zero common mode voltage and full scale signal inputs The 20 V range is the exception You cannot put 20 V on CHHI and 0 V on CHLO since this violates the input range criteria The table below shows some possible inputs and the expected results Sample inputs and differential results CHHI CHLO Result 20V Invalid 15V 5 Invalid 10V OV 10V 10V 10 V
29. tocol low speed and full speed Functional block diagram USB 1208LS functions are illustrated in the block diagram shown here USB 1 1 Compliant Interface Analog Input 8 SE 11 bit channels or 4 Diff 12 bit channels USB Analog Output Microcontroller 10 bit 2 channels Screw terminal I O connector Event Counter 32 bit 1 channel Screw terminal I O connector Figure 1 Functional block diagram Chapter 2 Installing the USB 1208LS Unpacking As with any electronic device you should take care while handling to avoid damage from static electricity Before removing the device from its packaging ground yourself using a wrist strap or by simply touching the computer chassis or other grounded object to eliminate any stored static charge Contact us immediately if any components are missing or damaged Installing the software Refer to the MCC DAQ Quick Start for instructions on installing the software on the MCC DAQ CD Refer to the device product page on the Measurement Computing website for information about the included and optional software supported by the USB 1208LS Install the software before you install your device The driver needed to run the USB 1208LS is installed with the software Therefore you need to install the software package you plan to use before you install the hardware Installing the hardware Be sure you are using the latest system software Before installing
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