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1. 1147 OL Od 1510 2 01 0724 e 23 32 8 hie e Ol 1 92 35311 40 13311 Z 31993 03073145 531 30 13314 Z 31993 03073145 3331 30 1334 Z 31843 03073145 27889 31H ld Lia 31993 03013153 Nid G Nid Sz NId Ge Nid Ge DUROS LS ge epes P ES S1lNIHJ SLN Hd Ld d 131718494 Aa LN lad eege 7 Im ld d 111180uud 7 m Ld d 13118348d Ld d 13110484 Fig 4 Printer Port System with Four 926s 3 4 PRINTER PORT VS DUAL PORT MEMORY INTERFACE You can purchase the Model 926 pre set for use with either the DPM USB Dual Port Memory to USB Interface Converter orthe printer port interface The DPM USB converter requires that the Dual Port Memory Interface option be installed If your 926 is configured for the Dual Port Memory Interface and you wish to convert to the printer port interface see Section 3 4 1 If the unitis configured for the printer port interface and you wish to convert to the Dual Port Memory Interface see Section 3 4 2 3 4 1 Installing the Printer Port Interface Ifthe Dual Port Memory Op2. 131135083 lt CR gt The command was attempted while spectrum acquisition was in progress No action was taken SET LIVE PRESET ticks Sets the live time preset to the specified number of ticks During data acquisition when the live time counter reaches the preset number of ticks the preset is complete and the acquisition is stopped Setting a live time preset to O ticks disables the preset See also CLEAR PRESETS and SHOW LIVE PRESET Execution Errors 131135083 lt CR gt The command was attempted while spectrum acquisition was in progress No action was taken SET PEAK PRESET count Sets the ROI peak preset to the specified count During data acquisition when the contents of any channel of a device that has the ROI flag set reaches the peak preset count the preset is complete and the acquisition is stopped The actual number of counts in the ROI peak may exceed the preset value by a small number of counts due to the pipelined architecture of the 926 Setting a peak preset to 0 counts disables the preset The peak preset may be set to from 0 disabled to 2147483647 counts See also CLEAR PRESETS and SHOW PEAK PRESET Execution Errors 131135083 lt CR gt The command was attempted while spectrum acquisition was in progress No action was taken SET ROI start chan number of chans Sets the ROI flags for the specified channels This command can be used multiple times to set ROI flags without affecting previously set flags ROI flags specify
3. 94 INSTALLATION EE RE RO End Nac Me S ipi RR BER S 2 31 LIVE TIMEMODE eue eR deter IIR ae Rt ee ja Daer ave oto deg lad Pra e Bean DATE eee 3 2 2 MGB ADDBESS aiaa va nella he ipft a alee nid eb ge Ha Paese ad om wa ee 3 3 3 MCB PRN JUMPER FOR PRINTER PORT CONNECTION 3 3 4 PRINTER PORT VS DUAL PORT MEMORY INTERFACE 6 3 4 1 Installing the Printer Port Interface lille 6 3 4 2 Installing the Dual Port Memory Interface 6 3 50 CABLING A SYSTEM 5 nue eru SERERE RDUM Ee a dr ER E M ata 6 3 6 ADJUSTING THE LOWER LEVEL DISCRIMINATOR s sese e 8 3 7 SETTING THE ZERO ADJUSTMENT ssssseee hrs 8 3 8 ENABLING THE OGATEINPUT RR mu hn 8 Dee 9 4 1 MGB OPERATION iet RERUM e RE E i REM xe Rex RU RR a BEES 9 4 2 DEAD TIME IN MCA AND AMPLIFIER oocccccccccc ete 10 5 TROUBLESHOOTING GUIDE 11 5 1 DUAL PORT MEMORY DOES NOT EIST 11 5 2 BATTERY BACKUP FAILS ooo urere REPRE UE DEED RR URL PAX RE RE 11 APPENDIX A FIRMWARE COMMANDS AND RESPONSES 0000 sees 11 A T GONNECTIONS 92 4 x 45d cue dd a da EEN Ee Terre bau 11 A 2 COMMAND RECORDS 11 A 3 PERCENT RESPONSE RECORDS 000 0 rne 12 AA DOLLAR RESPONSE RECORDS susseseels eres 13 A 5 COMMAND CATALOG c ooocccoccc lh rere 13 APPENDIX B GLOSSARY ooo 21 SAFETY INSTRUCTIONS AND SYMBOLS This manual contains up to three levels of safety instructions that must be observed in order to avoid personal injury and
4. No action was taken CLEAR ROI The region of interest flags for the channels in the window of interest see SET WINDOW command are cleared Execution Errors 96131135083 The command was attempted while spectrum acquisition was in progress No action was taken DISABLE ALARM Ends the transmission of alarm responses when acquisition stops See also ENABLE ALARM and SHOW ALARM DISABLE OVERFLOW PRESET Disables the overflow preset Channels that receive a count when they contain 2147483647 counts the maximum number of counts will roll over to zero counts if the overflow preset is disabled See also ENABLE OVERFLOW PRESET and SHOW OVERFLOW PRESET ENABLE ALARM Begins the transmission of alarm responses E records when an input stops counting A E response record will be transmitted only when no host commands are being processed after a 96 response from a previous command and before another command is sent See also DISABLE ALARM and SHOW ALARM ENABLE OVERFLOW PRESET Enables the overflow preset Channels that receive a count when they contain 2147483647 counts the maximum number of counts will stop the acquisition for that channel s device if the overflow preset is disabled The channel that caused the preset to complete will contain 214783647 counts An alarm response record will be sent to the host if alarms are enabled see ENABLE ALARM command See also DISABLE OVERFLOW PRESET and SHOW OVEHRFLOW PRESET commands INITIALI
5. G0000000001076 lt CR gt Peak preset set to 1 count G2147483646120 lt CR gt Peak preset set to 2147483646 counts G2147483647121 lt CR gt Peak preset set to 2147483647 counts SHOW ROI Used in conjunction with the SHOW NEXT command SHOW ROI reports the first continuous group of channels that have the ROI flag set The response is of the form Dsssssnnnnnccc CR where sssss represents an integer number that is the number of the first channel of the first group of channels that all have their ROI bit set and nnnnn represents an integer number that is the number of channels in the group The SHOW NEXT command is used to report the next group of channels that all have their ROI bit set Responses D0100000050078 lt CR gt First ROI group starts at chan 1000 and is 50 chans long D0215000150086 lt CR gt First ROI group starts at chan 2150 and is 150 chans long D0000000000072 lt CR gt No ROI groups to report SHOW_TRUE Reports the contents of the true time counter in units of 20 milliseconds 50 ticks per second See also CLEAR_COUNTERS and SET_TRUE Responses G0000000000075 lt CR gt True time reported as 0 ticks G0000000001076 lt CR gt True time reported as 1 tick 20 milliseconds G4294967295132 lt CR gt True time reported as 4294967295 ticks over 23000 days SHOW_TRUE_PRESET Reports the current true time preset in units of 20 milliseconds 50 ticks per second See also CLEAR_PRESETS and SET_TRUE_PRESET R
6. 2 3 INPUTS INPUT Accepts positive unipolar positive gated integrator or positive leading bipolar analog pulses in the dynamic range from O to 10 V 12 V maximum semi Gaussian shaped or gated integrator shapedtime constants from 0 25 to 30 us or delay line shaped with width 20 25 us Zn 1 KQ dc coupled No internal delay BNC connectors on front and rear panels ADC GATE Optional slow positive NIM input Computer selectable Coincidence or Anticoincidence Signal must occur prior to and extend 0 5 us beyond the peak of the pulse front panel BNC connector Z 1 KQ PUR Pile up rejection input accepts slow positive NIM signal signal must occur prior to peak detect Zi gt 1 KQ BNC connector on rear panel BUSY Busy input used by live time correction circuits Accepts slow positive NIM signal signal must occur prior to peak detect Za gt 1 kQ BNC connector on rear panel 2 4 INTERFACE CONNECTORS PARALLEL PORT Provides for control of the instrument and access to the data memory from a standard PC printer port Rear panel mounted 25 pin D shaped male connector PRINTER Optional connection provided to either connect to another 926 MCB or a printer to the System Rear panel mounted 25 pin D shaped female connector DUAL PORT MEMORY Optional 37 pin D connector provides the PC with a communication link and direct access to the Model 926 s internal data memory The DUAL PORT MEMORY connector replaces the PRI
7. CONVERSION 2048 CR Conversion gain set to 2048 channels SET GAIN CONVERSION 4096 CR Conversion gain set to 4096 channels SET GAIN CONVERSION 8192 lt CR gt Conversion gain set to 8192 channels SET GATE ANTICOINCIDENT Causes the MCB to expect the ADC gate input signal in anticoincident mode See the section on the ADC gate input for more information See also SET GATE OFF SET GATE COINCIDENT and SHOW GATE SET GATE COINCIDENT Causes the MCB to expect the ADC gate input signal in coincident mode See the section on the ADC gate input for more information See also SET GATE OFF SET GATE ANTICOINCIDENT and SHOW GATE SET GATE OFF Causes the MCB to ignore the state of the ADC gate input signal See the section on the ADC gate input for more information See also SET GATE COINCIDENT SET GATE ANTICOINCIDENT and SHOW GATE SET INTEGRAL PRESET count Sets the ROI integral preset to the specified count During data acquisition when the sum of the counts contained in the channels of a device that have the ROI flag set reaches the integral preset count the preset is complete and the acquisition is stopped The actual number of counts in the ROI integral may exceed the preset value by up to 512 counts due to the pipelined architecture of the 926 Setting an integral preset to 0 counts disables the preset The integral preset may be set to from O disabled to 4294967295 counts See also CLEAR PRESETS and SHOW INTEGRAL PRESET Execution Errors
8. also SET_GATE_OFF SET_GATE_COINCIDENT and SET_GATE_ANTICOINCIDENT Responses FOFF lt CR gt Reports the ADC gate is off or ignored FCOI lt CR gt Reports the ADC gate is in coincident mode FANT lt CR gt Reports the ADC gate is in anticoincident mode SHOW INTEGRAL start chan number of chans Reports the sum of the specified group of spectral data channels If start chan and number of chans is not provided SHOW INTEGRAL reports the sum of all channels that have their ROI flag set Responses G0000000000075 lt CR gt Integral reported as 0 G4294967294131 lt CR gt Integral reported as 4294967294 G4294967295132 lt CR gt Integral reported as greater than or equal to 4294967295 maximum reportable value SHOW_INTEGRAL_PRESET Reports the current ROI integral preset value See SET_INTEGRAL_PRESET for more information about the ROI integral preset See also SHOW_INTEGRAL Responses G0000000000075 lt CR gt Integral preset reported as 0 G4294967295132 lt CR gt Integral reported as 4294967295 SHOW_LIVE Reports the contents of the live time counter in units of 20 milliseconds 50 ticks per second See also CLEAR_COUNTERS and SET_LIVE Responses G0000000000075 lt CR gt Live time reported as 0 ticks G0000000001076 lt CR gt Live time reported as 1 tick 20 milliseconds G4294967295132 lt CR gt Live time reported as 4294967295 ticks over 23000 days SHOW_LIVE_PRESET Reports the current live time preset in units o
9. as follows 9eaaabbbccc CR where represents the ASCII 96 character aaa represents the macro error code bbb represents the micro error code ccc represents the checksum and CR represents the ASCII carriage return character signifying the end of the record The macro error code represents the general class of error with O meaning no error and the micro error code represents the sub class of error with O meaning no error The following table lists all percent responses for a Model 926 Unconditional Success 9000000069 No Errors Detected START STOP Warnings 956000005074 MCB already started or stopped 956000006075 Preset already exceeded Power Up Alert 96001000070 All power up selftests passed 956003000072 Battery backed up data lost 96005002076 ROM failed selftest TEST Command Results 95004002075 ROM failed selftest Command Syntax Errors 96129001082 Invalid verb in command 96129132087 Invalid command verb noun and modifier valid but not together 130128084 Incorrect checksum only if checksum provided 130129085 Command record too long 96131128085 Invalid 1st parameter Communication Errors Execution Errors A 4 DOLLAR RESPONSE RECORDS SHOW commands respond with a single dollar response record followed immediately by a percent response record All valid dollar response records for each command are listed in the command The following table lists the general form of each dollar r
10. channels Some parameters listed in the command dictionary are considered optional and are distinguished from mandatory parameters by being surrounded by brackets in the command prototype line e g SET WINDOW start length Commands that have optional parameters may be sent to the MCB without the optional parameters in which case the behavior will be changed as explained in the command description An optional checksum may be added to the end of any command sent to an MCB The checksum is a 1 byte unsigned integer sum of all of the characters in a command treated as unsigned integers up to and including the comma or space s that separates the checksum from the command The checksum simply appears as an extra parameter added to the end of the command parameter list For commands that do not normally have parameters the checksum appears as the only parameter separated from the header by one or more spaces All optional parameters must be included in a command if a checksum is to be provided so that the checksum is not mistaken by the MCB as a parameter For example the SET WINDOW command must include the two optional parameters start and length if the checksum SET WINDOW 0 8192 159 is provided eg A 3 PERCENT RESPONSE RECORDS The 926 MCBs respond to all commands with a percent response record that signifies the completion of the command Percent response records contain two error code numbers and a 1 byte checksum
11. channels within a device that are considered for ROI integral and ROI peak presets SET TRUE PRESET ticks Sets the true time preset to the specified number of ticks During data acquisition when the true time counter reaches the preset number of ticks the preset is complete and the acquisition is stopped Setting a true time preset to O ticks disables the preset See also CLEAR PRESETS and SHOW TRUE PRESET Execution Errors 131135083 lt CR gt The command was attempted while spectrum acquisition was in progress No action was taken SET WINDOW start length Sets the window of interest to the specified start channel and number of channels The channels of spectral data in the window of interest are affected by commands such as CLEAR and SET DATA If neither start or length is provided the window is set to the maximum size allowed by the conversion gain specified for the currently selected device The window of interest is always set to the maximum size after a SET DEVICE command or a SET SEGMENT command Execution Errors 131128085 lt CR gt The start channel was too high for the conversion gain 131129086 lt CR gt The length specified one or more channels that were too high for the currently selected device s conversion gain 131132080 lt CR gt The start channel was specified without a length If one value is given the other must be also given SHOW ACTIVE Returns a 1 if the ADC is active acquiring spectral data or O i
12. quality control tests designed to expose any flaws in materials or workmanship Permanent records of these tests are maintained for use in warranty repair and as a source of statistical information for design improvements Repair Service If it becomes necessary to return this instrument for repair it is essential that Customer Services be contacted in advance of its return so that a Return Authorization Number can be assigned to the unit Also ORTEC must be informed either in writing by telephone 865 482 4411 or by facsimile transmission 865 483 2133 of the nature of the fault of the instrument being returned and of the model serial and revision Rev on rear panel numbers Failure to do so may cause unnecessary delays in getting the unit repaired The ORTEC standard procedure requires that instruments returned for repair pass the same quality control tests that are used for new production instruments Instruments that are returned should be packed so that they will withstand normal transit handling and must be shipped PREPAID via Air Parcel Post or United Parcel Service to the designated ORTEC repair center The address label and the package should include the Return Authorization Number assigned Instruments being returned that are damaged in transit due to inadequate packing will be repaired at the sender s expense and it will be the sender s responsibility to make claim with the shipper Instruments not in warranty should follow the sa
13. to 65535 but is ignored by the Model 926 Execution Warnings 96000005074 Acquisition already stopped no changes made mask Performs any combination of the internal selftests where mask represents a 16 bit integer with each bit set specifying a test as follows Bit 0 LSB ROM checksum test nondestructive Bit 1 Spectral data memory test destroys spectral data Bit 2 Processor memory test destroys spectral data Bit 3 RESERVED Bit 4 RESERVED Bit 5 Mailbox memory test may cause mailbox comm error Execution Errors 004002075 lt CR gt ROM failed test 004008081 lt CR gt Processor Memory failed test 004016080 lt CR gt Spectral Data Memory or Mailbox Memory failed test The actual response record may be a combination of any of the above records depending on the selftests performed For example 004010074 lt CR gt Processor Memory and ROM1 both failed test APPENDIX B GLOSSARY ACQUISITION The process of collecting data from a detector and storing the data in memory ALARM RESPONSE RECORD The response record that is sent to the host computer when one or more devices are stopped ASCII American Standard Code for Information Interchange The ASCII code is defined by ANSI American National Standards Institute Standard X3 4 1977 This standard describes the representation of characters as 8 bit binary numbers This representation for characters is used by most mini and personal computers 22 CHECKSUM The
14. ESS The Model 926 can be installed in a system with multiple ORTEC MCBs However to prevent hardware conflicts when using older MCBs it might be necessary for you to manually change the MCB address for one or more instruments If connecting to your PC with a DPM USB interface converter no MCB address change is needed leave the unit s address at the factory default setting of 1 If changing older 926s from the legacy DPM ribbon cable interface to the DPM USB converter make sure each unit is set to address 1 MAESTRO and other CONNECTIONS 32 programs support a maximum of 127 USB connections If connecting multiple 926s via the printer port every MCB in the system must be assigned a unique MCB address You may find it useful to mark the front panel of each instrument with its MCB address Figures 3 and 4 show two printer port systems with the jumper settings for the various 926s Once an address is established for each MCB in the system the hardware must be set to that address On the Model 926 the address is set with the rotary Switch highlighted in Fig 2 To access this switch remove the right side plate The switch should be set to 1 less than the MCB address For example if the MCB address is 1 set the switch to 0 3 3 MCB PRN JUMPER FOR PRINTER PORT CONNECTIONS The MCB PRN jumper must be correctly set when the printer port interface is used To connect an MCB only If the jumper is in the MCB position an MCB c
15. Model 926 ADCAM Multichannel Buffer Hardware Manual Printed in U S A ORTEC Part No 761630 0210 Manual Revision G Advanced Measurement Technology Inc a k a ORTEC a subsidiary of AMETEK Inc WARRANTY ORTEC warrants that the items will be delivered free from defects in material or workmanship ORTEC makes no other warranties express or implied and specifically NOWARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ORTEC s exclusive liability is limited to repairing or replacing at ORTEC s option items found by ORTEC to be defective in workmanship or materials within one year from the date of delivery ORTEC s liability on any claim of any kind including negligence loss or damages arising out of connected with or from the performance or breach thereof or from the manufacture sale delivery resale repair or use of any item or services covered by this agreement or purchase order shall in no case exceed the price allocable to the item or service furnished or any part thereof that gives rise to the claim In the event ORTEC fails to manufacture or deliver items called for in this agreement or purchase order ORTEC s exclusive liability and buyer s exclusive remedy shall be release of the buyer from the obligation to pay the purchase price In no event shall ORTEC be liable for special or consequential damages Quality Control Before being approved for shipment each ORTEC instrument must pass a stringent set of
16. NTER connector on the rear panel when installed 2 5 ELECTRICAL AND MECHANICAL POWER REQUIRED 12 V 200 mA 12 V 200 mA 6 V 600 mA WEIGHT Net 0 9 kg 2 Ib Shipping 2 25 kg 5 Ib DIMENSIONS NIM standard single wide 3 43 x 22 13 cm 1 35x8 714 in front panel per DOE ER 0457T 3 INSTALLATION 1 Install the accompanying version of our MAESTRO 32 MCA Emulation Software and the CONNECTIONS 32 Update Kit if included according to its instructions Depending on the 926 to PC interface you will use mark the appropriate checkbox on the installation wizard s Instrument Family page as follows e lf using a DPM USB interface converter to attach the 926 to the PC mark the DPM USB checkbox e f connecting via the printer port mark the DART or any other printer port based device checkbox 2 Select the live time correction mode Section 3 1 3 If using a DPM USB interface converter the MCB address must be set to the factory default of 1 If this is a new instrument it is ready to use without modification Install the DPM USB converter according to its instructions 4 Ifconnecting via the printer port see Section 3 3 for instructions on setting the MCB PRN addressing jumper 5 To switch between the DPM and printer port interfaces see Section 3 4 6 Cable the spectroscopy system together and connect it to the PC 7 Power on the 926 If the Windows found new hardware wizard opens follow
17. ZE Resets the Model 926 hardware and software as though the following commands had been issued STOP SET WINDOW 0 8192 SET GATE OFF TEST 1 CLEAR ALL SET GAIN CONVERSION 0 Execution Errors The INITIALIZE command simulates a power down power up cycle for the MCB after a simulated loss of battery backed up memory Thus the 96 response record is the response from the Power Up Alert 003000072 lt CR gt MCB Power up occurred Memory lost No selftest errors Normal Response for INITIALIZE command 007002078 lt CR gt All of above but selftest failed ROM failed RESET Resets the 926 to the state just after power is applied This command responds with a response that indicates power up just occurred SET_DATA count Sets all channels of spectral data in the window of interest see SET_WINDOW command for the currently selected device see SET_DEVICE command to the specified count ROI flags are not affected SET_GAIN_CONVERSION chans Sets the conversion gain The conversion gain defines the number of channels within the device that will used for spectral data This has the effect of altering the resolution of the ADC from 13 11 bits conversion gain 8192 2048 to 9 bits conversion gain 512 for the device Legal Commands SET_GAIN_CONVERSION 0 lt CR gt Conversion gain set to default 8192 SET GAIN CONVERSION 512 CR Conversion gain set to 512 channels SET GAIN CONVERSION 1024 CR Conversion gain set to 1024 channels SET GAIN
18. al and converts it to a digital equivalent e Zero Level Lower Level and Upper Level Discriminators The discriminators provide 3 control signals which help control the conversion process The Zero Level Discriminator ZLD is active when the input signal is greater than 1 2 of the Lower Level Discriminator setting The Lower Level Discriminator LLD is active when the input signal is greater than the Lower Level Discriminator setting The Upper Level Discriminator ULD is active when the input signal is greater than the maximum possible ADC output The Lower Level Discriminator settings is set with a screwdriver adjustment on the front panel e ADC Control This circuit accepts all of the various status signals and provides the control signals required to complete a conversion Analog to Digital Microprocessor Converter Data Ready e ZLD goes active when the input reaches 1 2 of the LLD setting e When ZLD goes active the peak stretcher is switched to Hold mode e When Peak Detect goes active LLD PUR GATE and ULD are sampled If any of these signals rejects the pulse then the Peak Stretcher is returned to Track mode If the pulse is accepted the Linear Gate is closed and the ADC is given the convert signal e When the ADC is finished converting the data is transferred to the microprocessor for histogramming the Linear Gate is opened and the Peak Stretcher is returned to Track mod
19. an be connected to the PRINTER connector To connect a printer and MCB If the jumper is in the PRN position a printer can be connected to the PRINTER connector on the rear panel of the Model 926 The jumper is set to MCB when the Model 926 leaves the factory To change the MCB PRN jumper remove the right side plate of the Model 926 by removing the four screws Figure 1 shows the location of the jumper Place the jumper across the right two pins for PRN and across the left two pins for MCB Figures 3 and 4 show how the MCB PRN jumper should be set for a single MCB and a multi MCB system MCB Switch Address Setting MCB address switch Test jumpers Leave jumpers in position shown MCB PRN jumper Live time mode Extended Simple Fig 2 Model 926 Address Switch and Jumpers PRIMER PARALLEL PORT 25 PIN SHIELDED ST ANDA RD CABLE 4 l F1 PRINTER CABLE 9374 0 10 TO LPTI UU PERSONAL CONPUTER FER PANEL POORESS Zi CH P HCE PFM JUNPER PRN FACTORY SETTINGS gt Fig 3 Single Model 926 Using Printer Port Interface PRINTER JIH dado Nad fon JIH uadunn Nad es oe JIH uidHnn Nad Soon Had u3dH r Neos oon H31ndWHU3 IWNOSdad Y HILIAS 5534004 HOLTAS S3939008 Z HILIAS 3330089 E HOLAS 5539008 713HH4d 3033 VaNdd ud3d 13MHd udid VaNdd Hd3d 44 LN 3d 26 926 926 KI
20. ar records are composed of printable ASCII characters and end with an ASCII carriage return ROI CHANNEL A channel that has the ROI flag set ROI FLAG A set of internal MCB flags one for each channel which when set identifies the channel as being part of the region of interest All channels in a device that have the ROI flag set are considered when ROI integral or ROI peak presets are evaluated ROM Read Only Memory 23 SCRATCHPAD MEMORY The RAM memory inside the 926 MCB that is used for various overhead operations The scratchpad memory is all the memory that is not used for storage of spectral data or mailbox communications SEGMENT A subdivision of a device Segments are not implemented on 926 MCBs and are referenced only for compatibility with other MCBs SELFTEST A test of internal MCB components initiated by the TEST command or MCB power up TICK The minimum unit of time associated with a clock such as the real time or live time clocks a clock tick TRUE REAL TIME The actual time that data acquisition is active regardless of the MCB s ability to process detector pulses True time is also known as real time WINDOW OF INTEREST The continuous group of channels affected by commands like CLEAR and SET DATA The window of interest is set by the SET WINDOW command as well as by the SET DEVICE and SET SEGMENT commands 24 INDEX ADC gale s ira tecta hate te etit tra a saeculo Eege nat ara intu Cite do aset ase
21. ction contains a very basic description of the input circuitry and the chain of events that occurs in the Model 926 when an input pulse arrives to be histogrammed Figure 7 shows the basic block diagram of the input section of the Model 926 First a description of each block in the circuit e Buffer The buffer is provided to properly match impedances between the input and the Model 926 circuitry e Linear Gate The Linear Gate protects the peak stretcher during conversion of an event When the Linear Gate is open its output is identical to its input When the Linear Gate is closed its output is always zero e Peak Stretcher The peak stretcher operates in one of two modes Track or Hold In Track mode the output of the peak stretcher is identical to its input In Hold mode the peak stretcher acts like a maximum function It outputs the maximum Linear Linear Gate Zero Level Lower Level Upper Level Discriminators Fig 7 Model 926 Input Block Diagram e Microprocessor The microprocessor accepts the digital data and adds it to the spectrum Upon arrival of an input pulse the sequence of events is as follows Gate Stretcher Control value which is applied to the input The Peak Stretcher also has a Peak Detect output which goes active when its output is greater than the value at its input e Analog to Digital Converter The Analog to Digital Converter ADC takes an analog sign
22. d This setting is adequate for most systems If the system has high noise or there is a very low energy peak in the spectrum it may be advantageous to adjust the LLD setting In the high noise system start collecting data and observe the dead time on the screen along with the number of counts arriving at the low end of the spectrum With asmall screwdriver turn the LLD adjustment on the front panel clockwise until the dead time drops or the peaks due to noise at the low end of the spectrum stop getting new counts If there is a low energy peak in the spectrum it may be necessary to lower the LLD setting to preventthe peak from being rejected Start data acquisition and observe the low end of the spectrum while turning the LLD adjustment on the front panel counterclockwise Continue the adjustment until the peak is in the spectrum Caution Do not lower the adjustment such that the dead time goes to 100 3 7 SETTING THE ZERO ADJUSTMENT The Zero Adjustment is provided to add or subtract a dc level from the input signal The Zero Adjustment is on the front panel of the Model 926 Usually no zero adjustment is required or recommended since most modern spectroscopy amplifiers have very little dc offset Should offset adjustment be necessary turn the screwdriver adjustment clockwise to move peaks in the spectrum to the right and counterclockwise to move them to the left 3 8 ENABLING THE GATE INPUT The Gate on the front panel o
23. dollar response record which begins with an ASCII dollar sign followed by a percent response record The WRITE command can respond with multiple pound sign records which begin with an ASCII pound sign but eventually completes by sending a percent response record All other commands result in a single percent response record upon completion A 2 COMMAND RECORDS The Model 926 commands consist of a command header which may be followed by numeric parameter values The header consists of a verb or a verb and noun separated by an underscore or a verb noun and modifier each separated by underscores The verbs nouns and modifiers in the command header are mnemonic words such as the verb ENABLE or the noun OVERFLOW that relate to the function performed by the MCB when it executes the command The first four letters of any word will always be enough to uniquely identify the word when composing commands for an MCB For example the command ENABLE OVERFLOW PRESET can be abbreviated to ENAB OVER PRES Numeric parameters are unsigned integer numbers that follow the command header separated by one or more spaces Specific commands require up to three parameters separated by commas which specify numeric quantities related to the operation of the MCB such as live time or conversion gain The command SET WINDOW 0 8192 has two parameters 0 and 8192 which set the window of interest to start at channel O and continue for 8192
24. e 4 2 DEAD TIME IN MCA AND AMPLIFIER When a detector preamplifier spectroscopy amplifier and MCA are combined to form a spectroscopy system the dead times of the amplifier and the MCA are in series see Fig 8 The combination of the amplifier extending dead time followed by the MCA non extending dead time Ty yields a throughput described by r I O expl Tu Tt w TATu Ty TA The rate of events arriving at the detector is r and r is the rate of analyzed events in the MCA spectrum Ty is the width of the amplifier pulse at the noise discriminator threshold Figure 7 Tp is the time from the start of the amplifier pulse to the point at which the MCA detects peak amplitude and closes the linear gate U T Ty T is a unit step function that changes from 0 to 1 when T is greater then Ty Tp Ty is the conversion time of the ADC and includes the time required to transfer the data to the subsequent memory The 926 Extended Live Timer utilizes the Gedcke Hale method to correct for the dead time losses implied by the equation above When the counts in a full energy peak are divided by the live time the resulting counting rate is an accurate estimate of the true counting rate for that gamma ray energy at the detector output The Gedcke Hale method uses the amplifier analog output BUSY and PUR Pile Up Reject signals The amplifier dead time is combined with the ADC conversion and readout dead time to obtain the overa
25. enabled IF lt CR gt Overflow preset disabled SHOW_PEAK This command returns the contents of the ROI channel with the largest number of counts An ROI channel is a channel that has the ROI flag set The maximum possible value is 2147483647 which is the maximum number of counts that can be stored in a 31 bit channel Responses G0000000000075 lt CR gt Maximum count in an ROI channel is zero or no ROI channels were found G0000000001076 lt CR gt Maximum count in an ROI channel is 1 G2147483646120 lt CR gt Maximum count in an ROI channel is 2147483646 G2147483647121 lt CR gt Maximum count in an ROI channel is 2147483647 SHOW PEAK CHANNEL This command returns the number of the ROI channel with the largest number of counts An ROI channel is a channel that has the ROI flag set The lowest number ROI channel with the largest count is reported if more that one channel contains the largest number of counts Channel 16383 is the highest numbered channel in any device Responses C00000087 lt CR gt Maximum count was found in channel 0 or no ROI channels were found C00001088 lt CR gt Maximum count was found in channel 1 C08190105 lt CR gt Maximum count was found in channel 8190 C08191106 lt CR gt Maximum count was found in channel 8191 20 SHOW PEAK PRESET Reports the value of the ROI peak preset See SET PEAK PRESET for information about the ROI peak preset Responses G0000000000075 lt CR gt Peak preset disabled
26. esponse record for a 926 MCB In this table lowercase letters represent numeric values The letters ccc always represent an 8 bit unsigned checksum of all characters on the record up to but not including the checksum characters and CR represents the ASCII carriage return character Fsssss ssss is a variable length ASCII character sequence No checksum is sent with this record dictionary A 5 COMMAND CATALOG This section lists each Model 926 command with a description of its operation The descriptions include a list of any unusual responses that may result As described in previous sections the usual response from a command is a 000000069 lt CR gt response which represents a macro error code of 0 and a micro error code of O no errors All execution error responses if any are listed for each command Though syntax and communication error responses may result from any command in practice these error responses rarely occur on Systems with reliable communication hardware running debugged software Refer to the section on Percent Response Records in this Appendix for information about error responses In the following catalog the commands are listed in alphabetical order each starting with a command prototype line Uppercase letters numeric digits blank space and special symbols such as the underscore and comma in the prototype line are literal text to be sent to the MCB exactly as it appears Lo
27. esponses G0000000000075 lt CR gt True time preset reported as disabled G0000000001076 lt CR gt True time preset reported as 1 tick G4294967295132 lt CR gt True time preset reported as 4294967295 ticks SHOW_VERSION Reports the firmware version number in the form Fmmmm vvv lt CR gt where mmmm is a 4 character model designator and vvv is a 3 character version designator Example Responses F0926 001 lt CR gt Model 926 firmware version 1 reported 21 SHOW WINDOW Reports the start channel and number of channels that are in the window of interest for the currently selected device in the form Dxxxxxyyyyyccc lt CR gt where xxxxx is the start channel 0 through 8191 and yyyyy is the number of channels 1 through 8192 See SET WINDOW for more information about the window of interest Example Responses D0000008192092 lt CR gt Window of interest reported as starting at channel O and continuing for 8192 channels START seg mask Starts the acquisition of spectral data The optional segment mask is provided for compatibility with other MCBs and may be any value from 0 to 65535 but is ignored by the Model 926 Execution Warnings 000005074 lt CR gt The acquisition is already started no changes made 000006075 lt CR gt A preset was exceeded acquisition was not started STOP seg mask Stops the acquisition of spectral data The optional segment mask is provided for compatibility with other MCBs and may be any value from 0
28. f 20 milliseconds 50 ticks per second See also CLEAR_PRESETS and SET_LIVE_PRESET Responses G0000000000075 lt CR gt Live time preset reported as disabled G0000000001076 lt CR gt Live time preset reported as 1 tick G4294967295132 lt CR gt Live time preset reported as 4294967295 ticks SHOW_MODE This command is for compatibility with Model 918 systems It always reports that the 926 operates in pulse height analysis mode Responses FPHA lt CR gt SHOW NEXT Used in conjunction with the SHOW ROI command SHOW NEXT reports the next continuous group of channels that have the ROI flag set The response is of the form Dsssssnnnnnccc lt CR gt where sssss represents an integer number that is the number of the first channel of the next group of channels that all have their ROI bit set and nnnnn represents an integer number that is the number of channels in the group If no more channels have their ROI bit set SHOW NEXT returns a first channel of 0 and a number of channels of 0 The SHOW ROI command is used to report the first group of channels that all have their ROI bit set Example Responses D0100000050078 lt CR gt Next ROI group starts at chan 1000 and is 50 chans long D0215000150086 lt CR gt Next ROI group starts at chan 2150 and is 150 chans long D0000000000072 lt CR gt No other ROI groups to report SHOW_OVERFLOW_PRESET Reports the state of the overflow preset Responses IT lt CR gt Overflow preset
29. f it is not active Responses C00000087 CR The ADC is not active C00001088 lt CR gt The ADC is active SHOW_ALARM Returns a record that indicated whether the alarm responses are enabled or disabled Responses IT lt CR gt Alarms are enabled IF lt CR gt Alarms are disabled SHOW_CONFIGURATION Returns a record that indicates the hardware configuration of the MCB The record contains information about the number of segments in an MCB device always one for the 926 and the current conversion gain for each segment The record is organized as follows J0819200001aaaaa00000 65 zeros here for total of 75 zeros 00000ccc for 8K J0204800001aaaaa00000 65 zeros here for total of 75 zeros 00000ccc for 2K Where aaaaa represents the conversion gain for the one and only segment in the currently selected device and ccc represents the record checksum See the section on response records in this appendix for more information about response records and checksums SHOW GAIN CONVERSION This command returns the conversion gain Responses C00512095 lt CR gt Conversion gain reported as 512 channels C01024094 lt CR gt Conversion gain reported as 1024 channels C02048101 lt CR gt Conversion gain reported as 2048 channels C04096106 lt CR gt Conversion gain reported as 4096 channels 8K only C08192107 lt CR gt Conversion gain reported as 8192 channels 8K only SHOW_GATE Reports the current mode of operation of the ADC gate input See
30. is XE le b deb E ER oe edt a o Vet qo deb od ob LE RUE Aen ede 2 att 1 Printer port interface 1 3 6 PUR EE 2 R gion ot Interest assis gx RE S Re duce xe e M Res PCR Sed A e CR e E ede ws RU a Bg 14 RESET E E EE EE 15 isse 1 FOL ee LEE O O rura ar fa E pa aea fL e 19 ROUflags e t pe wu Le ee eet Lebel EA RU E valeur b qoe eot eia n E tad 16 BR ln EE 14 M CIERRE A A A A ec as ha 20 Window ot interest 14 Zero Adjustment i fase cel rra rd trc esie Bide ede Ree ihe feeb PLE MUS A daa 8
31. l 926 has battery backup to maintain data when power is turned off The battery used is a lithium battery with a nominal voltage of 3 V To replace battery Remove the right side plate Locate battery on the top right corner of the 926 see Figure 1 Remove the old battery from the holder and slide a new one in It may be necessary to bend the battery holder down after removing the old battery to get good contact with the new battery BATTERY SPECIFICATION P N 739480 Lithium coin cell APPENDIX A FIRMWARE COMMANDS AND RESPONSES Software communication with the DSPEC Pro takes place through the CONNECTIONS 32 software layer CONNECTIONS 32 is used by all ORTEC software and can be accessed for other software development with our CONNECTIONS 32 Programmer s Toolkit with Microsoft ActiveX Controls A11 B32 A 1 CONNECTIONS 32 In CONNECTIONS 32 the communication consists of sending command records to the MCB API and receiving response records from the MCB API Both command and response records consist of a sequence of printable ASCII characters followed by an ASCII carriage return The single exception to this rule is the B response record for the WRITE command which contains binary integer numbers All commands eventually respond with a percent response record so named because the response begins with an ASCII percent sign which signifies the completion of the command SHOW and STEP commands respond with a
32. ll system dead time For accurate live time the PUR and BUSY signals must be connected from the amplifier to the 926 Fig 8 The Sources of Dead Time with an Amplifier and MCA The Gedcke Hale live time clock works as follow e Either the leading edge of the amplifier BUSY signal or the crossing of the ADC Lower Level Discriminator LLD by the ADC input causes the live time clock to start counting backwards e Thelive time clock is turned off by the ADC peak detect or by the amplifier PUR signal e The live time clock resumes counting forward after all of the following signal conditions are satisfied The ADC conversion and readout is complete The ADC input has returned below the LLD threshold The PUR and BUSY signals have returned to the inactive state Turning off the live time clock compensates for the probability of losing a second pulse during the processing of the first pulse Subtracting live time compensates for the probability of losing two pulses when the second pulse distorts the amplitude of the first pulse 5 TROUBLESHOOTING GUIDE This section of the manual contains some troubleshooting hints to help when something goes wrong Below are listed several common problems and possible solutions 5 1 DUAL PORT MEMORY DOES NOT EXIST e Carefully review the instructions in Section 3 2 and ensure that the MCB address has been properly set 5 2 BATTERY BACKUP FAILS The memory in the Mode
33. me procedure and ORTEC will provide a quotation Damage in Transit Shipments should be examined immediately upon receipt for evidence of external or concealed damage The carrier making delivery should be notified immediately of any such damage since the carrier is normally liable for damage in shipment Packing materials waybills and other such documentation should be preserved in order to establish claims After such notification to the carrier please notify ORTEC of the circumstances so that assistance can be provided in making damage claims and in providing replacement equipment if necessary Copyright O 2010 Advanced Measurement Technology Inc All rights reserved ORTEC is a registered trademark of Advanced Measurement Technology Inc All other trademarks used herein are the property of their respective owners CONTENTS SAFETY INSTRUCTIONS AND SYMBOLS 0 0000 hr iv SAFETY WARNINGS AND CLEANING INSTRUCTION iv 1 DESCRIPTION v besser aisect iu A A LS awed ithe EA La eebe 1 14 GENERAL i a em bee eed dd Y Ro DECR EROR UE Xe dedi ee Dre dedi aca e red as dg Rok eee 1 1 2 INTENDED AUDIENCE sssseeee hh 1 2 SPECIFICATIONS x 8 pel had ee a Bel a ag eed Ee Ae Pe ha eet a 1 241 PERFORMANCE 5 5 35 ARIETE IBI RD TUE S iue aiU SV Steere de drea 1 2 2 INDICATORS AND CONTROLS coco 1 2 3 INPUTS xcd ere reae eme E idet AA AAA E A Rede e 2 2 4 INTERFACE CONNECTORS ooo 2 2 5 ELECTRICAL AND MECHANICAL 2
34. n Fig 6 YALNAHOD UNOS 1d OY1S30H 13404 13T119HUd uo Au0OWiM LHOd luna TINGS Bese TENSd Seid que A ddns Sura e49 651 YO 099 659 TANYA dy ad oz o 3 D 0 0 0 0 5 6 28886 ES EH i e e OO OSC 00 OO OSC OO QO Q60 QO Eon d Weve Zeie Zeie Zeie 0999 Kastel Beie 30309 SS De o o NAO00LNHS 310438 E NADO LNHS sera dit add oboe 209 GEES E ES DEE i HERE ER SSC S1ndino LEBIHNE 383N17 LS 110A H9IH rr TEES A 1 1un4 El 19na SLMANI H3A0d dodddd inding LL IHNI Fig 6 HPGe Cabling Diagram If the detector has a TRP preamplifier PLUS model all connections shown should be made If the preamplifier is a resistive feedback preamplifier the INHIBIT OUTPUT does not exist so the connection to INHIBIT is not made INHIBIT is left open 3 6 ADJUSTING THE LOWER LEVEL DISCRIMINATOR The Lower Level Discriminator LLD adjustment is used to prevent small noise pulses from being converted by the ADC Converting the noise pulses causes the ADC to incur a large amount of dead time thereby preventing the ADC from converting the actual pulses of interest When the Model 926 is shipped from the factory the LLD setting is approximately 75 mV so no pulses smaller than 75 mV are converted or histogramme
35. or damage to equipment or other property These are DANGER Indicates a hazard that could result in death or serious bodily harm if the safety instruction is not observed WARNING Indicates a hazard that could result in bodily harm if the safety instruction is not observed CAUTION Indicates a hazard that could result in property damage if the safety instruction is not observed Please read all safety instructions carefully and make sure you understand them fully before attempting to use this product In addition the following symbol may appear on the product A ATTENTION Refer to Manual AN DANGER High Voltage Please read all safety instructions carefully and make sure you understand them fully before attempting to use this product SAFETY WARNINGS AND CLEANING INSTRUCTIONS DANGER Opening the cover of this instrument is likely to expose dangerous voltages Disconnect the instrument from all voltage sources while it is being opened WARNING Using this instrument in a manner not specified by the manufacturer may impair the protection provided by the instrument Cleaning Instructions To clean the instrument exterior e Unplug the instrument from the ac power supply e Remove loose dust on the outside of the instrument with a lint free cloth e Remove remaining dirt with a lint free cloth dampened in a general purpose detergent and water solution Do not use abrasive cleaners CAUTION To prevent moisture inside of the in
36. perates in one of three modes e Off The Gate Input does nothing e Coincidence For a pulse to be converted the Gate Input must be active 22 5 V when the pulse reaches its peak and for 0 5 us thereafter e Anticoincidence For a pulse to be converted the Gate Input must be inactive 0 8 V when the pulse reaches its peak and for 0 5 us thereafter When the Model 926 is shipped from the factory the Gate Input is set Off To change the Gate Input mode a SET GATE command must be sent to the 926 This command can be sent within MAESTRO 32 by creating an ASCII text JOB file Create a JOB file as follows to set the gate to Coincidence Go to the Services menu Select Job Control Select Edit File takes you to Notepad Type Pon 2 SEND MESSAGE SET GATE COIN 5 Save as COIN JOB then exit Notepad 6 Refresh display by reentering Job Control 7 Select COIN JOB and click on OK To set gate to Anticoincidence or to disable the GATE replace COIN in Steps 4 and 5 with ANTI or OFF Refer to the MAESTRO User s Manual for more information on creating JOB files The Gate Mode setting is stored in the 926 s memory so the command or JOB file need only be executed once unless the battery fails 4 MCA BASICS The first half of this section describes the circuitry found on the Model 926 board MCB while the second half describes the dead time effects encountered in an MCA 4 1 MCB OPERATION This se
37. strument during external cleaning use only enough liquid to dampen the cloth or applicator e Allow the instrument to dry completely before reconnecting it to the power source vi ORTEC MODEL 926 ADCAM MULTICHANNEL BUFFER 1 DESCRIPTION 1 1 GENERAL The ORTEC Model 926 Multichannel Buffer MCB is a NIM module designed for high performance data acquisition in nuclear spectroscopy applications ORTEC offers MCA emulation software and quantitative analysis software for almost every application The Model 926 can be configured to connect to a PC with our DPM USB Dual Port Memory to USB Interface Converter or viathe legacy parallel printer port interface The DPM USB converter one converter per 926 unit makes it simple to connect multiple 926s and other ORTEC USB MCBs to the host PC s native USB ports and or powered USB hubs You can also connect a daisy chain of 926s to the PC s printer port 1 2 INTENDED AUDIENCE This manual describes the initial installation and setup of the Model 926 Section 2 gives the Model 926 specifications for reference Section 3 tells how to install and configure the Model 926 Section 4 describes the basics of MCA operation Section 5 gives some troubleshooting information The appendix is intended for the user who wishes to write custom software to control the Model 926 IT explains the commands used to control the system 2 SPECIFICATIONS 2 1 PERFORMANCE ADC Successive appro
38. sum of bytes in a record used to detect when communication errors occur CLOCK A component of a device that keeps track of some form of time 926 MCBs have live time and true time clocks COUNTER Another name for a 926 clock live time or true time DEAD TIME The time that data acquisition is active but the MCB cannot process detector pulses is dead Dead time is equal to the true time minus the live time for a device DEVICE The entity within an MCB that collects and stores spectral data A device corresponds to the MCB s inputs Model 919 MCBs have 4 inputs and thus 4 devices while 926 MCBs have only 1 input and thus 1 device A device can be started stopped cleared and selected HOST The computer that sends commands to an MCB and receives responses from the MCB LIVE TIME The time that data acquisition is active and the MCB is capable of processing detector pulses is live Live time is equal to the true time minus the dead time for a device PRESET A limit set for a clock or region of interest count that if exceeded during an acquisition will cause the acquisition to stop 926 MCBs have live time true time ROI integral ROI peak and overflow presets for each device in the MCB PROGRAM MEMORY The ROM memory inside the 926 MCB that contains the microprocessor instructions and fixed data that control the operation of the MCB RAM Random Access Memory RECORD A sequence of related bytes 926 command percent and doll
39. t a eiat rate o eege aue ara 2 16 17 ADG BK EECH 1 ADC ZOO atan cnn XML Cn n Vn 1 Alarm responses 15 17 Analog to Digital Converter 9 Battery sx ue be C ins ERG HIS ERE VAS ker ey De VALE Pe eS LEE VANUS Mee eR eg 11 BUS ia messed tet A a Deed Ee 2 el ele TEE 15 Data Memo Y sicario was a IIR UM PUT T 11 13 DEM o a e tee e eee uer vous ld e cur o tia ca e fecto S 1 Differential Nonlinearity o oooooooorrrrrn RR RR RII IRR s Hh hh 1 DDPNEUSB nterfaee 2 0 icut ut Zanen A DDR Zanen ar deg LEVE 1 3 6 Firmware version ia Dee UP eb rs de VR ER eee a E Te C Y p aie Vea TE C VLC ex 20 e uM occ 8 Gedcke EFlalo wu idas Medus o ca fu a a t Ea efte EEN 3 10 Integral 14st sy gale ged a Poh a ENEE 18 Integral Nonlinear o cire vice it EE SEN esie bie bie Sed TED sd bee Le SEN e bc bie he 1 Integral preset i ose Seek Pene Ite Eine risp Pee ELE DONE See Paces R DR EUR E Peur s EUN DANEK eto 18 Linear Gale uta ra rs ener lerem a e a ec a ce Ln on d edP Das data De Le NATU eO o ovatae qd Le oo ad cd 9 JEE ce eae Ca d e e e EO re E ap ER o 14 Lower Level Discriminator llle RR RR RR A hes 8 Overflow preset ene eae Res et Sie diag ORG D ORA DR e RR age Cus CR ie o atl ale He DR 14 19 PEAK sr anto EE Vul dera unto d aod E Voted ee Eh 19 Peak GHhannel LL arr nv SI Tue ctv Aa ce oi lee ein ua teeth Puce E 19 Peak Stretcher 2 soa is a Lat ov Po add erat ce a tct ata UL aT oec ee P da arta 9 POWER zu cs tithe tet Sa
40. ter 3 4 2 Installing the Dual Port Memory Interface If your 926 is configured for the printer port interface and you wish to use the Dual Port Memory interface instead two steps are necessary the instrument must be reconfigured and you must purchase either the DPM USB Dual Port Memory to USB Interface Converter or the classic Dual Port Memory Interface ribbon cable from ORTEC To reconfigure the 926 you must install the Dual Port Memory Option which is included with each 926 It is a 37 pin ribbon cable with a 37 pin D connector on one end and a 40 pin header on the other end To install the Dual Port Memory Option do the following referring to Fig 5 Dual Port Memory Connector Printer Connector Fig 5 Location of Option Connectors 1 Remove the right side plate by removing the four screws which hold it in place 2 Remove the two Phillips screws that hold the PRINTER panel in place 3 Slide the PRINTER panel out of the rear panel slot 4 Disconnect the PRINTER option from the Model 926 board by pulling straight up on the header which connects the ribbon cable to the board Store the cable and screws in a safe place Carefully plug the Dual Port Memory option Slide the connector into the rear panel of the 926 Secure the connector with 3 16 hex nuts and washers provided 8 Replace the side plate noo 3 5 CABLING A SYSTEM The standard cabling of a 926 in a HPGe detector system is shown i
41. the prompts choosing a to not go to the internet to find the driver and b to automatically locate the driver If the wizard cannot locate the driver direct it to C Program Files Common Files ORTEC Shared UMCBI 8 Runthe MCB Configuration program to build the list of available MCBs according to the MAESTRO User s Manual 9 To adjust the lower level discriminator and the zero level see Sections 3 6 and 3 7 respectively Section 3 8 describes the gate input 3 1 LIVE TIME MODE The Model 926 has two different live time correction modes Extended and Simple The Extended mode is the Gedcke Hale correction mode which corrects for losses caused by pileup in the shaping amplifier This is the default setting and is usually the correct setting for energy spectroscopy systems The Simple Live Time correction mode simply stops the live time clock when the BUSY signal is active the Model 926 detects that a pulse is arriving at its input or the 926 is busy digitizing data The Simple Live Time mode is appropriate only in very specialized situations and is not the correct setting for most users To change the live time correction mode remove the right side plate of the Model 926 by removing the four screws Figure 2 shows the location of the live time correction mode jumper Place the jumper across the lower two pins for Extended Live Time correction and across the upper two pins for Simple Live Time correction 3 2 MCB ADDR
42. tion has been installed in the 926 the Printer Option must be reinstalled if a printer or second MCB is to be connected to the 926 To install the Printer Option do the following 1 Remove the right side plate by removing the four screws which hold it in place 2 Using a 3 16 nut driver remove the two hex nuts which hold the Dual Port Memory DPM connector to the rear panel 3 Slide the connector out of the rear panel slot 4 Disconnect the DPM cable from the Model 926 board by pulling straight up on the header which connects the DPM cable to the board 5 Store the cable hex nuts and washers in a safe place 6 Carefully plug the Printer Option in to the row of pins close to the rear panel see Figure 4 The connector is keyed for proper installation 7 Slide the other end of the cable into the rear panel of the 926 Secure the connector with two Screws 8 Replace the side plate Figures 3 and 4 show wiring diagrams for several printer port systems The cables used are 25 pin shielded male female cables The cable from the computer to the first Model 926 should be no longer than 10 feet 3 meters Cables connecting additional 926s should be no longer than 2 feet 0 6 meters These cables are available from ORTEC by ordering Model 926 C 10 for a 10 foot cable and Model 926 C 2 for a 2 foot cable The cable used to connect a Model 926 to a printer is a standard printer cable which normally connects a computer to a prin
43. wercase letters in the prototype line represent numeric values as described in the accompanying text and should not be sent literally to MCB but should be replaced by an appropriate numeric value Items in the command prototype that are surrounded by brackets are optional items and are not always required In this section the term CR represents the ASCII carriage return character decimal value 13 and the character represents the ASCII underscore character decimal value 95 the CLEAR The channels of spectral data in the window of interest see SET WINDOW command are set to zero The live time and true time counters are also set to zero This command is equivalent to the combination of CLEAR COUNTERS and CLEAR DATA commands CLEAR ALL This command is equivalent to the combination of CLEAR COUNTERS CLEAR DATA CLEAR PRESETS and CLEAR ROI commands Execution Errors 131135083 lt CR gt The command was attempted while spectrum acquisition was in progress No action was taken CLEAR COUNTERS The live time and true time counters are set to zero CLEAR DATA The channels of spectral data in the window of interest see SET WINDOW command The ROI flags are not changed nor are the presets changed CLEAR PRESETS The live time true time ROI integral ROI peak and overflow presets are all set to zero disabled Execution Errors 96131135083 The command was attempted while spectrum acquisition was in progress
44. ximation type with sliding scale linearization Max Resolution Software selectable as 8192 4096 2048 1024 and 512 Dead Time per Event 8 us including memory transfer Integral Nonlinearity lt 0 025 over the top 99 of the dynamic range Differential Nonlinearity lt 1 over the top 99 of the dynamic range Gain Instability lt 50 ppm C Dead Time Correction Printed wiring board jumper selects either Extended Live time correction according to the Gedcke Hale method or Simple Live Time correction with the clock turned off during the conversion time Ron Jenkins R W Gould and Dale Gedcke Quantitative X Ray Spectrometry New York Marcel Dekker Inc 1981 pp 266 267 Data Memory 8K channels of battery backed up memory 2 1 counts per channel over 2 billion Presets e Real Time Live Time Multiples of 20 ms e Region of Interest Peak count Integral count e Data Overflow Terminates acquisition when any channel exceeds 27171 Microprocessor Intel 80C188 32K Dual Port RAM with battery backup 16K scratchpad RAM with battery backup 32K program memory 2 2 INDICATORS AND CONTROLS CPU BUSY Red busy rate LED intensity indicates the relative activity of the microprocessor ADC BUSY Red busy rate LED flashes once for each pulse digitized by the ADC ADC ZERO Front panel screwdriver potentiometer 250 mV ADC LLD Front panel screwdriver potentiometer from 0 to 10 full scale
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