Home

User Manual - Pyramid Technical Consultants

1. Questionable Questionable Event Condition Event Enable i S Register Register o Register QUEStionable tru ct u re Voltage 0 0 0 a Current 1 1 1 a I 400 Time 2 2 8 2 Pd Power 3 3 3 gt STATus Temperature 4 HH 4 4 Er 5 PP T15 5 gt gt 6 6 QH 6 PH 7 7 p gt Logical Calibration 8 8 8 ia OR 9 9 Bow 9 a Error 10 10 10 bh Queue 11 To HKH n a 12 12 ES 12 gt 13 13 13 gt 14 14 14 gt notused 15 15 15 gt CONDition EVENt ENABle Standard Service Standard Event Status Request Event Status Byte Enable Status Enable Register Register Register Register avail avail Operation Complete 0 m avail avail 1 gt gt Eav HS Eav Query Error 2 P gt QSB QSB Device Dependent Error 3 Logical MAV MAV Execution Error 4 La OR c ESB Command Error 5 gt RQS User Request 6 gt gt _OSB 8 Power On 7 po ESR ESE ESE EAV Error Available QSB Questionable Summary Bit MAV Message Available N ESB Event Summary Bit Operation Operation Pee RoS Request tor Service Condition Event Enable OPERation OSE Operation Summary Bit Register Register Register Calibrating 1 i 1 1 1 gt Ranging 2 2 8 2 L 3 3 3 p Measuring 4 4 4 p Waiting for Trigger 5 5 5 p 6 6 6 gt 7 7 7 Logical Saving to EEPROM 8 IL 8 8 La OR 9 _9 9 gt 10 10 8 10 p 11 11 11 p 12 12 E
2. Sw2 Sw2 a o sa 1 Integrating on Cy E 2 Collecting on C 6 fb fo AAA Swi EA Sw1 Sw2 Sw2 7 O 3 Reset integrator Co 4 Collecting on C Cr EP Swi peia Swi l ma o E o o E p f o i Sw2 Sw2 Pr W h 5 Transfer charge Co 6 Integrating on on C Ci from C to Ch DEA m Sw 1 NA RE AAA RAT Sw 1 Figure 21 Switching sequence for the no lost charge method Consider the integrator working normally with charge accumulating on Cw and thus voltage increasing at the output 1 The mode 2 no charge loss reset cycle starts by opening the input switch Swl 2 If the load parallel resistance is high the only place that the source current can now go is to build up charge on Cs The integrator is now reset 3 by closing Sw1 charge continues to accumulate on Cs 4 When Sw1 closes again the accumulated charge transfers quickly to Cm This is because the effective input capacitance of the integrator is much greater that C due to the amplifier action 5 The integrator output voltage jumps upward as a result of the transferred charge Assuming lossless transfer the net result is to extend the integration time over the complete reset cycle so that all of the incoming charge is measured The integration now proceeds normally again 6 1400 User Manual 1400 UM_090105 Page 46 of 104 PSI System Controls and Diagnostics i t Swi i rrr t per effe
3. 1400 A500 A300 Hardware 1400 device 1400 FPGA PTC Diagnostic A500 boot A500 device A500 FPGA A500 Ethernet A300 FPGA revision code code version PROM code Rev 2 3 2K 1 3 3 3 26 1 9 4 15 2 6 18 RCM3200 3 3 Rev 2 4 04 1 3 3 4 06 1 11 5 06 2 7 38 A30 5 4 Rev 3 3 2K 1 4 2 3 26 1 9 4 15 2 6 18 RCM3200 3 3 Rev 3 4 0A 1 4 2 4 06 1 11 5 06 2 7 38 A30 5 4 1400 User Manual 1400_UM_090105 Page 103 of 104 PSI System Controls and Diagnostics 30 User Manual Revision History The release date of a Pyramid Technical Consultants Inc user manual can be determined from the document file name where it is encoded yymmdd For example M10_UM_080105 would be a M10 manual released on 5 January 2008 Version Changes 1400_UM_061212 1400_UM_080925 First general release Correct section numbering Correct errors and omissions in Section 5 optional items Change drawings and text to reflect change from push fit to ST bayonet fiber optic connectors Change drawings and text to reflect move to 3 lug triax connectors as standard with 2 lug now optional Add information on internal switches and jumpers 1400_UM_090105 Change section on trigger modes to include new external_Start_Stop mode Remove description of ASCII echo on off commands no longer supported Remove description of ASCII data wrap commands no longer supported Remove description of
4. Signal Bias If your 1400 has the signal bias high voltage option you can set the output voltage with the Set Value box The Max box allows you to constrain the settings to a particular maximum for example to protect sensitive equipment that cannot sustain the maximum voltage of the supply The feedback value is not generally as accurate as the setpoint but does allow you to see if the supply is being overloaded Note that your setpoint entry must have the correct polarity to set a 400 V supply to 250 V you must enter 250 External Bias If your 1400 has the auxiliary external high voltage option you can set the output voltage with the Set Value box The Max box allows you to constrain the settings to a particular maximum for example to protect sensitive equipment that cannot sustain the maximum voltage of the supply The feedback value is not generally as accurate as the setpoint but does allow you to see if the supply is being overloaded Note that your setpoint entry must have the correct polarity to set a 1000 V supply to 600 V you must enter 600 Trigger You can set various trigger options Internal setting allows the 1400 to free run and take data without the need for incoming synchronization signals Full details of trigger modes are given in section 13 You can set the logic sense on trigger or off trigger with the Gate Polarity selection Trigger points This p
5. 11 1 Connecting to the 1400 The PSI Diagnostic is a stand alone program which allows you to read graph and log data from the 1400 and set all the important acquisition control parameters It supports communication via any of the interfaces For some applications it may be adequate for all of your data acquisition needs Once the program has installed you can run it at once It will allow you to connect to the 1400 and depending upon your interface setup multiple additional devices at the same time The Diagnostic uses the concepts of ports and loops to organize the connected devices A port is a communications channel from your PS such as a COM port a USB port or and Ethernet port Each port can be a channel to one or more loops and each loop may contain up to 15 devices Inspect the unit carefully to ensure there is no evidence of shipping damage If there appears to be damage or you are in doubt contact your supplier before proceeding Connect 24 V DC power but no other connections The power LED should illuminate when the power is applied and the status and link LEDs will cycle through green orange and red see section 17 It is simplest to connect the 1400 directly to the PC via its RS 232 or USB ports figures 9 and 10 Using the USB interface you must install the USB driver see section 10 If you are using RS 232 set the mode switch to position 2 115 kbps binary If you are using USB set it to position 1 3 Mbps bina
6. 1400 User Manual 1400 UM_090105 Page 25 of 104 PSI System Controls and Diagnostics Found New Hardware Wizard Please select the best match for your hardware from the list below a E PTC 1400 Descnption Version Manufacturer Location PTCi400 3120 PTC c windows infioem42 inf PTCHO0 3120 PTC c documents and setiings iohn gordonimy docume gt A This driver is not digitally signed Tell me why driver signing is important lt Back Cancel If there is only one valid entry the wizard will proceed directly to the installation phase 4 Allow the installation to continue despite the driver not having the Windows Logo approval Hardware Installation A The software you are installing for this hardware PTC 1400 has not passed Windows Logo testing to verify its compatibility with Windows XP Tell me why this testing is important Continuing your installation of this software may impair or destabilize the correct operation of your system either immediately or in the future Microsoft strongly recommends that you stop this installation now and contact the hardware vendor for software that has passed Windows Logo testing Continue Anyway STOP Installation 5 The driver installation should now occur Found New Hardware Wizard Please wait while the wizard installs the software o gt PTC 1400 ES a Setting a system restore point and backing up old files in case your system needs
7. PSI System Controls and Diagnostics Found New Hardware Wizard This wizard helps you install software for PTC 1400 Q if your hardware came with an installation CD or floppy disk insert it now What do you want the wizard to do Install the software automatically Recommended Install from a list or specific location Advanced Click Next to continue lt Back Cancel 3 Using the browse option navigate to the location of the PTC INF file on the memory key supplied with the 1400 or to the appropriate directory on your computer The driver files and uninstall files should be in the same directory as PTC INF Found New Hardware Wizard Please choose your search and installation options e Search for the best driver in these locations Use the check boxes below to limit or expand the default search which includes local paths and removable media The best driver found will be installed Search removable media floppy CD ROM v Include this location in the search CADocuments and Settings John Gordon My Documents y C Don t search will choose the driver to install Choose this option to select the device driver from a list Windows does not guarantee that the driver you choose will be the best match for your hardware lt Back Next gt Cancel The wizard may find other inf files which also have valid entries depending on the history of your PC Select the PTC INF file
8. capacitor lt subsamp gt subsamples per period default 1 RANGe Query the full scale current range setting RESET lt reset gt lt settle gt lt setup gt Set the reset settle and setup times password protected RESET Query the reset settle and setup times 1400_UM_090105 Page 78 of 104 PSI System Controls and Diagnostics HIVOltage EXTernal MAXvalue lt volts gt MAXvalue VOLTS lt volts gt VOLTS SIGnal MAXvalue lt volts gt MAXvalue VOLTS lt volts gt VOLTS CONFigure DATa CLEar FEEd lt source gt FEEd POINts lt points gt POINts VALue lt source gt lt index gt STREAM FETCh CHArge CURRent DIGital present 1400 User Manual 1400_UM_090105 High voltage configuration External auxiliary high voltage Set maximum allowable external high voltage setting password protected Query maximum allowable external high voltage setting Set the external high voltage Query the external high voltage Signal input bias high voltage Set maximum allowable signal high voltage setting password protected Query maximum allowable signal high voltage setting Set the signal high voltage Query the signal high voltage Query the last CONFIGURE or MEASURE command Charge data Clear all data from 1400 Feed data according to source mask 1111 data from channels 1 2
9. 1400 Four Channel Digital Electrometer User Manual Pyramid Technical Consultants Inc 1050 Waltham Street Suite 200 Lexington MA 02421 USA US TEL 781 402 1700 FAX 781 402 1750 EMAIL SUPPORTOPTCUSA COM Europe TEL 44 1273 493590 PSI System Controls and Diagnostics 1 Contents J SANA AO O A NOOO SO NA A NO POWErSUPplleS ca lla A a ii 11 Signal cables and Cable ACCESSOTIES aiii iii eiii 11 DataiCables cat Ed Sasa eas E Aa a e ero ita E 12 FAD OR2 OPTIC LIA il iaS 12 Intended Use and Key Features ccscssscssssssscscscssssccsscssscscscsssssesssssscsscsnesssssccsscsssessscssccssessssssssssscsssesssesseessoee LO Intended Use edades 13 Key ECU a A A A A dista 13 Specification imac 14 Peccccccccccccccccccccccccccccccccccccccce Peccccccccccccccccccccccccccccccccccccccces Installation viicocioninncinnnc nnionscionoacicasss OS Y reer ry MOUNTS eiii 17 Grounding and power Supply cscscceceesecssesecseessceseeseesecseesecsceeccuseescssecssesecseeecsseescsaecasesecueesecnseeeesaecasesecseeseseaseeseaees 17 Connection 10 Signal SOUNCE ii A piensa Mist ETE SRNR Rk OS 18 Typical setup s acteasanieien target taints aided seis et eal are aie eel 18 Signal Cables 3 ce As teste states stadt dt ds AA ad ae 18 Signal current paths sireci caine As 19 Mounting orientato ci OR 19 Getting Started Using ASCII Communication ooo
10. 3 4 Query data feed mask Set the data buffer size limited to available data memory Query the data buffer size Read data from buffer at index Returns lt integration period chargel charge2 charge3 charge4 over range byte gt Stream data buffer contents to host get oldest buffer entry and clear from buffer Response is lt integration period charge1 charge2 charge3 charge4 over range byte trigger count gt where charge values are returned according to DATa FEEd setting Fetch data Fetch charge data lt integration period chargel charge2 charge3 charge4 over range byte gt Fetch current data lt integration period chargel charge2 charge3 charge4 over range byte gt Read digitals bit0 2 reserved bit3 HV enabled bit4 external gate Page 79 of 104 PSI System Controls and Diagnostics MONitor PRESsure TEMPerature FETCh INITiate PERiod lt period gt sub PERiod READ CHArge CURRent DIGital present MONitor PRESsure TEMPerature READ STATus OPERation CONDition ENABle ENABle EVENt QUEStionable CONDition ENABle ENABle 1400 User Manual Fetch monitor voltage input value Fetch pressure input value in pascals Fetch temperature input value in C Do same FETCH as last defaults to fetch charge if no defined last FETCh Initiate taking readings
11. No signal Small signal lost in noise Use longer integration time Signal does not vary as expected Integrators are overrange Overrange flags are set signal recovers if integration period is reduced Reduce the integration period or use the larger feedback capacitor Measured currents or charges are inaccurate by up to 15 Unit not calibrated Calibrate Calibration was carried out while a signal current was present Internal calibration source does not measure as 500nA with all inputs disconnected Repeat calibration with no external signal present High background offset Various causes Refer to section 21 current 500 nA background on all Internal calibration source has Turn off calibration source channels been turned on 1400 stops measuring Trigger points limit reached Measurement starts again if 1400 is reinitialized Adjust trigger points as required Data buffer full Measurement starts again if 1400 is reinitialized Adjust data points as required and or turn on data buffer wrap Communication link timeout Investigate and fix communications issue Use a longer timeout setting No or incorrect response to external trigger or gate Incorrect gate polarity selected Use correct polarity 1400 not configured to respond Use correct setup 1400 User Manual 1400_UM_090105 Page 95 of 104 PSI S
12. offset current Mitigation Typical noise after mitigation Triboelectric effects in 10 A Reduce cable lengths 10 A cable l Keep cable from moving Use low noise cable Current across 10 to 10 A Guard the sensitive node 10 A insulators from voltage o sorces Use triaxial cable AC interference 10 to 10 A Used screened triaxial cable 10 A AC AC interference 10 to 10 A Use integration periods that 10 A AC are an integer multiple of the dominant noise frequency Contaminated insulators 10 A Clean insulating surfaces with 10 A solvent Use air insulation where possible Keep humidity low Piezoelectric effects 10 to 10 A Avoid mechanical stresses and Negligible vibration in the sensor and cable Resistor Johnson noise lt 10 A None fundamental limit set by signal source resistance Temperature fluctuation 10 to 10 A fluctuation Temperature stabilize the whole measurement apparatus 10 to 10 A fluctuation Elevated temperature 10 to 10 A Reduce temperature of the whole measurement apparatus 10 A 1400 User Manual 1400_UM_090105 Page 90 of 104 PSI System Controls and Diagnostics 22 Beam position monitor readout A common application for the 1400 is readout of beam position monitors These can take the form of dual sensors for one axis position readout or quadrant sensors for simultaneous two axis
13. 104 PSI System Controls and Diagnostics Feedback capacitor Options ri a hna e t 70 Pressure and temperature sense Options ceeseceseeseesecseesecsecsecsseeessecsseeecaecasesecseesecsaseeeeaecaesecseeseenateeeeaees 70 Communications Interfaces sscssssersessrsersessrsersessssessessssessessssessessssesessessessssessessssessessssessessessssessessssessessssessesee 1 SOfEWATE protocol iia 73 COVE VIC E eee 73 ASCITP rOtOCO lui id A dan iia aie 74 MESSAGES td A Ad 74 Status TESIStElS ia 74 Host Commands viniste 76 ADDRESSING DEVICE Sii a dd 76 IEEE 488 2 MANDATORY COMMANDS 0 ceccssssssssseecesecseeecseesecsaeeecsaecasesecseesecnaseecsaeceseeesaeceenesaeeaeens 77 IEEE 488 2 OPTIONAL COMMANDS viiene eero ease Ea e oe e E E e a Ea i e 78 HOO COMMANDS e e itn danse donnie die dash A E E a a E a a E 78 ASCH Protocol Terminal Mod dida EE 83 Eight bitbinary protocol erene e a beds WALES e a dd a eie e a Ee E EEE e aa ET 83 Software A esteos saesson aapa eoar os nasie ras O NO Techniques for Making Low Current Measurements csscssscsssssscssscssscscssscccscssccssccsscssscssscsssscssscsssssessseeseee O 7 GuUAarding and Screening iii dactilar 87 RARA NE NS 88 LIDO electric elec titi titi Daan e e ah evade te dees dieta dirt td 89 Fault findins sasore souseran soseo e aarete aae enans esascs oers a s a a a D 1400 User Manual 1400 UM_090105 Page 5 of 104 PSI System
14. 400 V DC and this voltage must be generated by the 1400 input bias supply not by an external voltage source All four inputs of the 1400 must be at the same voltage In applications where high energy charged particle beams can strike electrodes which are normally connected to the 1400 voltages limited only by electrical breakdown can build up if the 1400 is not connected to provide the earth return path The user must ensure that a suitable earth return path is always present when the particle beam may be present The unit must not be operated unless correctly assembled in its case Protection from high voltages generated by the device will be impaired if the unit is operated without its case Only Service Personnel as defined in EN61010 1 should attempt to work on the disassembled unit and then only under specific instruction from Pyramid Technical Consultants The unit is designed to operate from 24VDC power with a maximum current requirement of 500mA A suitably rated power supply module is available as an option Users who make their own power provision should ensure that the supply cannot source more than 1000mA 1400 User Manual 1400_UM_090105 Page 7 of 104 PSI System Controls and Diagnostics A safety ground must be securely connected to the ground lug on the case Some of the following symbols may be displayed on the unit and have the indicated meanings Direct current Earth ground terminal Protective cond
15. ASCII identify command no longer supported Add section on beam position monitor readout Add hardware version section Add firmware versions section 1400 User Manual 1400_UM_090105 Page 104 of 104
16. a 140 mm by 180 mm rectangular pattern for more convenient fixing to surfaces with a corresponding pattern of M4 threaded holes or studs The mounting position should allow sufficient access to connectors and cable bend radii 100 mm minimum clearance is recommended at either end of the device Best performance will be achieved if the 1400 is in a temperature controlled environment No forced air cooling is required but free convection should be allowed around the case 8 2 Grounding and power supply A secure connection should be made using a ring lug from the M4 ground lug to local chassis potential This is the return path for any high voltage discharge passing via the 1400 24 VDC power should be provided from a suitably rated power supply with the following minimum performance Output voltage 24 0 5 VDC Output current 500 mA minimum 2000 mA maximum Ripple and noise lt 100 mV pk pk 1 Hz to 1 MHz Line regulation lt 240 mV The 1400 includes an internal automatically re setting PTC fuse rated at 1 1 A However the external supply should in no circumstances be rated higher than the 1400 connector limit of 5 A and a maximum of 2 A is recommended 1400 User Manual 1400 UM_090105 Page 17 of 104 PSI System Controls and Diagnostics 8 3 Connection to signal source 8 3 1 Typical setup Figure 3 shows a typical installation in schematic form Four quadrant readout electrodes in a sign
17. as the charge pulse is integrated to be captured The current pulse waveform may then be reconstructed by the host computer system as the differential of the measured integral curve v v i ADC end settle V t ADC start i t reconstr Figure 23 Reconstruction of a current pulse waveform from sub integration samples 1400 User Manual 1400_UM_090105 Page 48 of 104 PSI System Controls and Diagnostics 13 5 Data Readout and Buffering 13 5 1 Dataflow The dataflow in the 1400 can best be understood by referring to figure 24 This shows the dataflow for a continuous current measurement but the details are very similar for other modes Host commands from the ASCII protocol are shown for reference More details of these can be found in the section on communication protocols Following setup of the acquisition mode trigger mode integration period and other parameters as required the 1400 is primed to acquire data by an initialize command The acquisition occurs when an internally generated trigger is received The figure shows schematically the input of four end start ADC differences al a2 a3 a4 acquired in an integration period t as a result of a trigger event These are converted to four floating point charge values cl c4 by multiplying by the respective gain factors gl g4 and the results are held in a temporary buffer together with the integration time and the flag representing the ove
18. be halted when a particular value is reached When charge accumulation is turned on a running total is kept of the total accumulated charge across all the integrations since the last initialize All reported and buffered charge values show this accumulating value If sub samples have been specified these are used as interim values to be added temporarily to the accumulating total They are superseded by subsequent sub samples in the same integration period up until the final sample which is logged permanently to the total 1400 User Manual 1400_UM_090105 Page 44 of 104 PSI System Controls and Diagnostics Charge added Charge added Interim charge from to accumulator to accumulator sub sample D gt o Charge missed o during reset o o o o o o o o Figure 20 Illustration of integrator voltage at ADC sampling points during charge accumulation The reset periods are shown relatively large There are three alternative means of dealing with the charge that is missed during the integrator resets These are no correction interpolation and no lost charge 13 2 1 No reset time correction Simply ignoring the loss during the deadtime can be appropriate when the deadtime is a very small fraction of the total time For example with one second integrations and a 10pF feedback capacitor the percentage deadtime is about 0 003 of the total time which is negligible 13 2 2 Reset time interpolation The 14
19. e senal cutre Vog current e V offset eO t tper Figure 28 An integration showing signal and noise contributions to the final output V offset 18 eliminated automatically by the operation of the 1400 because the charge is measured as k ADCy ADC so the offset cancels Background current is not eliminated automatically because it is indistinguishable from signal current at any moment in time The 1400 internal background current is small pA level and stable The background from the external circuit will generally be higher but depends greatly on the particular sensor or transducer Depending upon your measurement needs it may be appropriate to subtract the total background current if it is significant relative to the signal and relatively stable You should be careful of changes to the background which would render any such correction invalid however This could be due to changes in temperature or electrical noise Background nulling can be automated in the host software The background should be measured with a long integration period sufficient to get an accurate value and with no true signal present only the background current The resulting background current values ibga for each channel can 1400 User Manual 1400_UM_090105 Page 56 of 104 PSI System Controls and Diagnostics be subtracted from subsequent current readings either manually or in host software In charge measurement modes subtract ipag
20. ease of connection to existing systems and simple terminal programs Setting Function 0 9 bit binary 10 Mbps 1 8 bit binary 3 Mbps 8 bit binary 115 2 kbps 8 bit binary 57 6 kbps ASCII 3 Mbps ASCII 115 2 kbps 2 3 4 8 bit binary 19 2 kbps 5 6 7 ASCI 57 6 kbps 1400 User Manual 1400 UM_090105 Page 62 of 104 PSI System Controls and Diagnostics 8 ASCII 19 2 kbps 9 Reserved The switch setting works in conjunction with the connector sensor see section 16 17 2 2 Address switch 16 position rotary switch setting device address Choice of address is arbitrary but each device in a fiber optic loop system must have a unique address Setting Function 0 Reserved to loop controller 1 14 Available address settings 15 Reserved for loop broadcasts 1400 User Manual 1400 UM_090105 Page 63 of 104 PSI System Controls and Diagnostics 17 3 Front panel indicators 17 3 1 HVon Red LED Either or both of the HV supplies are enabled 17 4 Rear panel indicators 17 4 1 24V Green LED 24VDC power is present 5V DC DC converter is running 17 4 2 USB Green LED USB communication is active 17 4 3 RS 232 Green LED RS 232 communication is active 17 4 4 Optical Green LED Fiber optic communication is active 17 4 5 Xmit Green LED Data being transmitted from the unit 17 4 6 Rev Gree
21. model and message structure A simple terminal program such as Windows Hyperterminal is sufficient to establish communication with the device It is possible to communicate with multiple devices at different addresses on the same channel by selecting a particular address to be the listener device at any time The binary messaging is more efficient in its use of communications bandwidth It is fully deterministic with embedded addressing in the messages and immediate responses including error reports from the devices Pyramid provides software drivers and diagnostic host programs for users who wish to use binary communication protocols Eight bit binary is primarily intended for direct host to device communication for example via RS 232 or USB links Nine bit binary is reserved for the 10 Mbit s fiber optic channel and is highly recommended for larger systems with multiple addressable devices in a loop 1400 User Manual 1400_UM_090105 Page 72 of 104 PSI System Controls and Diagnostics 19 2 ASCII Protocol SCPI Standard Commands for Programmable Instruments SCPI is an extension of the IEEE 488 2 standard This was originally developed by Hewlett Packard for the HP IB later GP IB interface before being adopted by the IEEE and is widely used by manufacturers of measurement equipment The 1400 implements the 1999 0 revision of SCPI O 1999 SCPI Consortium 19 2 1 Messages The first bit of every eight bit group in a message
22. password protected O off 1 on In terminal mode ACK and NACK are not sent and OK or error response is sent for all valid commands that do not otherwise generate a response Query terminal mode setting Set timeout in seconds password protected O timeout disabled 1400 will go to unconnected state if no valid message is received in the timeout period Query timeout setting Return next error in the error event queue Set dominant noise frequency generally line frequency 50 or 60 Hz Enter the device password to allow access to protected functions Query the password Enable going to the safe state when unconnected 0 do not go to safe state when unconnected go to safe state when unconnected Query the safe state Set the device serial number max ten alphanumeric password protected Query the serial number Return the SCPI standard version Establish trigger conditions Query the trigger count since the last INITiate Set trigger delay for message trigger mode Query trigger delay Set the number of trigger points after an INITiate before acquisition stops Query the number of trigger points SOURce INTernallEXTERNAL_STARTIIEXTERNAL_START_STOPIMESSage SOURce 1400 User Manual Set the acquisition trigger source Query the trigger source 1400_UM_090105 Page 81 of 104 PSI System Controls and Diagnostics 19 3 ASCII
23. readout at a single plane transverse to the beam direction The sensors may intercept the beam directly for example biased blades that emit electrons when struck by a high energy photon beam or the interaction may be indirect for example electrodes in an ionization chamber or the readouts of photodiodes X X A B A B Figure 39 Single axis readout from a split sensor A B e Y A B C D A B C D X X A C B D A B C D D C Figure 40 Two axis readout from a quadrant sensor Provided that the beam dimensions are not small or large relative to the sensor dimensions then the position functions will be linear with actual beam position over a reasonable range The position functions shown in the figures have the ranges 1 lt X Y lt 1 In order to convert to physical units you can multiply the result by a gain factor This is the algorithm implemented by the PTC Diagnostic program 1400 User Manual 1400_UM_090105 Page 91 of 104 PSI System Controls and Diagnostics 22 1 Quadrant data screen 1400 7 Address 7 on USB 00000743 El a x Comms e Comnectea Pending Error Da E Data Current Quadrant Split Initiate Measuring Abort Triggering j oO Bs O Pres kPa Monitor V Sig Bias V Ext Bias V x 20 000 Averaging 4 X Y 100 000 Reset _ tx 3 Zero Set Clear 2 Last Error 9 27 44 PM CALIBRATI
24. the scaled positions along the two linear axes 1400 User Manual 1400_UM_090105 Page 93 of 104 PSI System Controls and Diagnostics 23 Fault finding Symptom Possible Cause Confirmation Solution High background current Resistive path to signal input due to missing or broken guard Disconnect input background should reduce to specification levels Ensure good guard integrity all the way to the signal source High humidity Problem varies with relative humidity Ensure there are no water absorbent insulators Reduce the humidity levels Internal contamination Background current remains high with inputs disconnected Contact your 1400 supplier for advice or to organize a return for cleaning High noise levels Integration time too short for signal being measured Noise level reduces with integration period Use an appropriate integration time for the signal level RF pickup Noise varies with cable position status of neighboring equipment Check integrity of outer screens of signal cables Line voltage pickup Noise level drops sharply if integration period is 16 7 msec 60 Hz or 20 msec 50 Hz Keep 1400 and signal cables clear of unscreened high current mains voltage Use integration periods N line frequency 1400 User Manual 1400_UM_090105 Page 94 of 104 PSI System Controls and Diagnostics
25. this port forces the 1400 to be a listening device 6 pin mini DIN male 9 pin D female Figure 5 RS232 connection cable from the 1400 to a PC serial port DB9 Pins are shown looking at the face of the connectors 4 Set the address rotary switch to position 4 address 4 and the mode rotary switch to position 6 ASCII communication 115 kbps 5 Configure a Windows Hyperterminal session to use COM or other available port on your PC as shown in the following figures A suitable Hyperterminal file is provided on the 1400 software CD ROM 1400 User Manual 1400 UM_090105 Page 20 of 104 PSI System Controls and Diagnostics COM1 Properties x Port Settings Bits per second 115200 sl Data bits 8 y Parity None a Stop bits 1 wal Flow control None ha Restore Defaults Figure 6 Hyperterminal COM port setup 1400 test Properties 2 x ConnectTo Settings Function arrow and ctrl keys act as Terminal keys Windows keys 2 Backspace key sends pole 21x C CrkH C Del Ctri H Space Ctr H ASCII Sending V Send line ends with line feeds Emulation Echo typed characters local VT52 v Terminal Setup m Yp y Line delay 0 milliseconds Telnetterminal ID vT52 Character delay 0 milliseconds Backscroll buffer lines 500 Play sound when connecting or disconnecting ASCII Receiving 7 Append line feeds to incoming line en
26. to be restored in the future 1400 User Manual 1400 UM_090105 Page 26 of 104 PSI System Controls and Diagnostics Found New Hardware Wizard Completing the Found New Hardware SY Wizard The wizard has finished installing the software for Fa PTC 1400 Click Finish to close the wizard When installation is complete the Your new hardware is installed and ready to use message balloon should appear You may be prompted to reboot your PC 10 2 Installing the PSI Diagnostic Program The program runs under the Microsoft Windows operating system with the 2 0 NET framework This has to be installed before the PSI Diagnostic Most new PCs have NET already installed It can be downloaded from the Microsoft web site at no charge The installer will alert you if the NET framework needs to be installed Install the PSI Diagnostic by running the PTCDiagnosticSetup msi installer and following the screen prompts Once the program has installed you can run it at once If you wish to view the files that have been installed navigate to Program Files Pyramid Technical Consultants Inc PTCDiagnostic Note two files in particular PTC_Controls DLL and version xml If you need to update your version of the PTCDiagnostic these are the files that need to be overwritten 1400 User Manual 1400 UM_090105 Page 27 of 104 PSI System Controls and Diagnostics 11 Getting Started using the PSI Diagnostic Host Program
27. 00 assumes that the measured charge in the last integration period may be pro rata extended over the total cycle tint tsetup treset tsettle The charge added to the accumulator for each integration cycle is thus k ADC ADC q lens per t setup T l reset T t senle end t per t per t a Face a t sente setup 13 2 3 No lost charge technique In critical dosimetry applications it may be important to know the total accumulated charge over a period of time without making any assumption about what happened during the integrator resets The 1400 can achieve this for signal sources that can be modeled as a capacitance in parallel with a very high resistance This is a good model for ionization chambers isolated electrodes that collect charged particles and photodiodes The method is to use the inherent capacitance of the sensor Cs to capture the charge during the integrator reset cycle then to transfer this charge onto the feedback capacitor at the start of the next integration The switching sequence is illustrated in figure 21 1400 User Manual 1400_UM_090105 Page 45 of 104 PSI System Controls and Diagnostics
28. 006 JA o Load z Trigger Points Say Enannei 30 1 IN Subsamples 10 V INFINITE INF a sl 1 External Bias Gain Factors Valid 10 pF 1000 pF DATa Accumulate Mode oer o 1 HEEE 1 None x 200 V Feed Log o 2 ME 2 1 1922 Set Value o 3 E 3 1 1805 Capacitor o Data Points o 4 EEZ 4 ME a PF E 50 RESet Tus Cmd 10 pF 1000 pF Reset 7 i IET Sete 2s EC Seup s MN Last Error 4 31 33 PM CONFIGUREHIVOLTAGESIGNALVOLTS 222 DataOutOfRange Figure 13 Setup tab 1400 running with default settings Investigate all the screen controls and displays Integration period These three controls select the current range Changes to the integration Range period result in the appropriate range being displayed for the selected feedback capacitor selection Alternatively you can alter the range and the Capacitor integration time will be altered to suit Commonly used values can be selected from the dropdown The smallest allowed integration time is 100 1400 User Manual 1400 UM_090105 Page 33 of 104 PSI System Controls and Diagnostics us Subsamples This is the number of subsamples taken per integration The default is one Accumulate mode This control determines whether charge readings are accumulated over several integrations and the method that is used to handle the deadtime when the integrator is being reset
29. 400 UM_090105 Page 99 of 104 PSI System Controls and Diagnostics 26 Support Manual and software driver updates are available for download from the Pyramid Technical Consultants website at www ptcusa com Technical support is available by email from support ptcusa com Please provide the model number and serial number of your unit plus relevant details of your application 1400 User Manual 1400 UM_090105 Page 100 of 104 PSI System Controls and Diagnostics 27 Declaration of Conformity Declaration of Conformity Issued by Pyramid Technical Consultants Inc 259 Bishops Forest Drive Waltham MA 02452 USA The undersigned hereby declares on behalf of Pyramid Technical Consultants Inc that the referenced product conforms to the provisions as listed Product 1400 Four Channel Digital Electrometer Year of initial manufacture 2006 Applicable Directives 73 23 EEC Low Voltage Directive Laws for electrical equipment within certain voltage limits 89 336 EEC EMC Directive Laws relating to electromagnetic compatibility Applicable Standards IEC 610101 2002 2nd Edition UL 61010 1 2004 EN 61326 1997 A1 1998 A2 2001 EN 55011 1998 A2 2002 EN 61000 6 2 2001 Electromagnetic Compatibility Generic Standard Immunity for Industrial Environments Issuing Agencies Safety TUV Rheinland North America 12 Commerce Rd Newton CT 06470 USA EMC TUV Rheinland North America 12 Commerce Rd Newton CT 06
30. 470 USA Applicable Markings TUV FCC CE Authorized by hs 7 President Pyramid Technical Consultants Inc Date s Lugast Z 2906 The Technical Construction File required by these Directives are maintained at the offices of Pyramid Technical Consultants Inc 259 Bishops Forest Drive Waltham MA USA A copy of this file is available within the EU at the offices of Pyramid Technical Consultants Europe Ltd 2 Chanctonbury View Henfield BNS 9TW United Kingdom 1400 User Manual 1400_UM_090105 Page 101 of 104 PSI System Controls and Diagnostics 28 Hardware Versions This user manual refers specifically to the 1400 at hardware revision 3 Revision 2 units were also supplied to customers Major differences between versions that are or have been in regular production are summarized below Revision Changes Rev 2 First production version Rev 3 Signal connectors 3 lug triax as standard previously 2 lug as standard Screen cover introduced over high voltage circuitry HV modules made demountable Fiber optic connectors ST type previously Versatile Link push fit 1400 User Manual 1400 UM_090105 Page 102 of 104 PSI System Controls and Diagnostics 29 Firmware compatibility The following combinations are compatible with the highlighted combinations the recommended ones that take most advantage of software improvements The configurations of compatible loop controllers are also given
31. 90105 Page 85 of 104 PSI System Controls and Diagnostics 21 Techniques for Making Low Current Measurements Measurements of currents of around 10 nA and below require some care to prevent unwanted interference that can distort the results In particular the conductor that carries the current to the 1400 input the sensitive node must be carefully isolated and guarded to ensure unwanted currents cannot flow into it When an unexpectedly high background offset current is seen the first thing to do is to check again with the signal input s disconnected from the 1400 This will isolate the problem to the external measurement circuit or within the 1400 itself 21 1 Guarding and screening If the sensitive node is separated from a voltage source such as a power rail by an insulating layer then a small current will flow through the finite impedance of the insulator V Voltage source J J J Insulator Figure 35 Offset current to unguarded input For example a 10 V conductor separated from the sensitive node by 1 Gohm of total resistance would drive in 10 pA of background current The maximum bias voltage of the 1400 could drive in 0 4 nA in similar circumstances If the insulation is compromised by contamination then the problem is magnified The solution is to provide a guard shield around the sensitive node at the same electrical potential Leakages c
32. B or fiber optic using ASCII protocols based upon SCPI or binary protocols RS 232 and USB are intended for direct connection to a host PC The fiber optic interface allows a full loop based system with multiple individually addressed devices Switchable test amp calibration source i vol i i pi i Signal bias Auxiliary i Switchable large feedback capacitor Q __ HV external HV gt Syl 0to400V Oto tkv i 4x gated i A A 24V DC i integrator i DC DC lt lt i 7 TTI i Temperature by P gt ADC Isoln Monitor 4 Y O Gate i Seria USB usB lt 4 gt SL gt ADC Isoln Y y E gt Y eH a x Lp FPGA Ey i Fiber optic sensor gt P gt ADC Isoln Pressure f i Figure 18 1400 block schematic 1400 User Manual 1400_UM_090105 Page 40 of 104 PSI System Controls and Diagnostics The ADCs convert simultaneously as needed up to a maximum rate of 250kHz Because the ADC conversion period can be considerably
33. Controls and Diagnostics Maintenance AAA O ssai LOO O ONO LL 102 Declaration of Conformity 103 Hardware version User Manual Revision History 1400 User Manual 1400 UM_090105 Page 6 of 104 PSI System Controls and Diagnostics 2 Safety Information This unit is designed for compliance with harmonized electrical safety standard EN61010 1 2000 It must be used in accordance with its specifications and operating instructions Operators of the unit are expected to be qualified personnel who are aware of electrical safety issues The customers Responsible Body as defined in the standard must ensure that operators are provided with the appropriate equipment and training The unit is designed to make measurements in Measurement Category I as defined in the standard A CAUTION The 1400 can generate high voltages as follows or 400 V DC at 1mA maximum Present on the central conductor and inner guard screen of the triaxial signal connectors or 1000 V DC at 1mA maximum Present on the central conductor of the SHV connector These voltages and currents are not classified as hazardous live under EN61010 but may nevertheless give a noticeable shock The user must therefore exercise appropriate caution when using the device and when connecting cables Power should be turned off before making any connections The maximum permissible voltage on an electrode connected to an 1400 input is
34. Help ela O8 o A Empty R RAMID x a A Technical Consultants Inc PSI Diagnostic v4 06 Select Ports for Autodetect Below IP 192 168 100 123 100 r LAN Broadcast Add IP Remove IP Figure 11 PSI Diagnostic Search Utility 1400 User Manual 1400 UM_090105 Page 30 of 104 PSI System Controls and Diagnostics 11 2 Data screen A few seconds after you click the Start button the program should find the 1400 plus any other devices Clicking on the 1400 entry in the explorer list in the System window will open the 1400 window figure 12 PSI Loop Diagnostic v4 06 ala x Actions Window Help elh 90 o A Z USB 00000743 BA 1400 7 a 1400 7 Address 7 on USB 00000743 Connected Pending Error Data Current Quadrant Split Initiat Measuring Triggering Temp C 7E 10 Pres kPa Monitor V iz Sig Bias V Ext Bias V XIY Gain 4E 10 X 1 000 6E 10 4 Y 1 000 pa E Y Range X Time kB Buffer Couple Mode Auto y Fast 2310 gt cir Fite oc stip gt Last Error Figure 12 Data current tab 1400 running with default settings showing background noise Initiate This button starts an acquisition with the parameters set on the setup tab If a starting trigger is present for example if you are in internal trigger mode then the acquisition will sta
35. IN8 BIN8 ASC8 ASC8 ASC8 ASC8 optic 10M 3M 115k 57 6k 19 2k 115k 115k 57 6k 19 2k BIN 8 8 bit nibble oriented binary BIN 9 9 bit full binary ASC 8 8 bit ASCII SCPI message format 1400 User Manual 1400_UM_090105 Page 71 of 104 PSI System Controls and Diagnostics 19 Communications protocols 19 1 Overview The 1400 supports three types of communication protocol selected according to the setting of the mode switch a An eight bit ASCII protocol messages compliant with SCPI The low seven bits are used to encode the ASCII character The eighth bit is only set for synchronization when the lt ACK gt lt BELL gt lt CR gt lt LF gt and lt ESC gt characters are transmitted b An eight bit binary protocol The first and last bytes of the entire command or reply have the eighth bit set and contain the address All other bytes in the messages are broken into two bytes encoded into the low nibble 4 bits thus never having the top bit set c A nine bit binary protocol Synchronization is done with the ninth bit The first and last byte of each message have the ninth bit set and contain the address and all other bytes are unmodified binary with the ninth bit clear ASCII messaging is provided for users who wish to use existing host software systems that provide convenient support for ASCII communications All the capabilities of the 1400 are available through a familiar virtual instrument
36. N TRIAX COMMS y SELECTOR ADDRESS SELECTOR HV ON LED 30 9 10 8 M4 GROUND LUG 127 ANALOG IN 8 7 amp MONITOR PORTS p 30 4 34 3 lt 21 mje 55 9 Figure 1 1400 chassis end panels Dimensions mm 1400 User Manual 1400_UM_090105 Page 15 of 104 PSI System Controls and Diagnostics 245 3 220 9 110 45 4X M4 HOLE REMOVE PADS FOR ACCESS 90 0 OPTIONAL BASE PLATE ALUMINUM BLACK 192 0 426 6 89 0 4X U 22054 8 THRU 70 0 COUNTER SUNK FOR 4X U 22054 8 THRU i COUNTER SUNKFOR Y E SUPPLIED l Figure 2 1400 case side and plan views above and optional mounting plate below Dimensions mm 1400 User Manual 1400 UM_090105 Page 16 of 104 PSI System Controls and Diagnostics S Installation 8 1 Mounting The 1400 may be mounted in any orientation or may be simply placed on a level surface A fixed mounting to a secure frame is recommended in a permanent installation for best low current performance as this can be degraded by movement and vibration Four M4 threaded holes are provided in the base on a 140 mm by 120 mm rectangular pattern see figure 2 The length of fastener running into these threaded holes should be in the range 8 mm to 13 mm The optional mounting plate provides four M4 clear through holes on
37. ONSAVE 203 CommandProtected Figure 41 Quadrant data tab The quadrant readout screen assumes you have the 1400 inputs connected as channel 1 A channel 2 B channel 3 C channel 4 D The algorithm is therefore A C B D y g B C D X Gy Y A B C D A B C D You can enter the gain factors Gx Gy independently for the two axes The current values used in the algorithms are those after zero offset subtraction and averaging The graphic shows the scaled position by a cross hair cursor and by the X and Y values The latest beam current values are shown around the graphic labeled by channel number 1400 User Manual 1400_UM_090105 Page 92 of 104 PSI System Controls and Diagnostics 22 2 Split data screen a 1400 7 Address 7 on USB 00000743 Connected DY Pending Error y y Current Quadrant Split Initiate Measuring Abort Triggering Gated 4 Last Error 9 27 44 PM CALIBRATIONSAVE 203 CommandProtected Figure 42 Split data tab The split data tab allows measurement of two independent axes These could be at separate positions along one beamline or even in two different beamlines The first nominally X uses data from channel 1 A and channel 4 B The second nominally Y uses data from channel 2 A and channel 3 B A B X Y G Y A B You can enter the gain factors Gx Gy independently for the two axes The diamond cursors show
38. Protocol Terminal Mode SCPI is not ideal for a user trying to control the 1400 from a terminal program A more interactive terminal mode can be turned on by sending the command SYSTem COMMunication TERMinal 1 After this command is executed the 1400 will provide a response to every command Valid query commands will get their normal reply Other commands will generate an lt OK gt response if they were interpreted without errors or an error message if they could not be interpreted The non printing ACK and BEL characters are not sent 19 4 Binary protocol The binary protocol is optimized for deterministic loop operation and is primarily intended for use with Pyramid Technical Consultants host software and software device drivers Users who wish to develop their own host software using binary communications are advised to use the supplied device drivers For further details refer to the 1400 Software Documentation The device model for the binary communications is essentially the same as for ASCII and particularly the terminal mode All host messages get an immediate response from the 1400 There are a range of summary level commands that are unavailable under SCPI For example the complete contents of the data buffer can be returned with a single command 1400 User Manual 1400 UM_090105 Page 82 of 104 PSI System Controls and Diagnostics 20 Software updates The 1400 has three embedded firmware releases Firmware F
39. S 12 a 13 13 HH 13 gt Program running 14 _14 14 15 15 15 HL CONDition EVENt ENABIe Figure 32 SCPI Status register structure 1400 User Manual 1400_UM_090105 Page 74 of 104 PSI System Controls and Diagnostics 19 2 3 Host Commands The 1400 responds to the mandatory commands prescribed by SCPI and IEEE 488 2 plus specific commands as required by the operation of the device The commands are grouped with a hierarchical structure with the levels separated by the colon character For example CONFigure GATe INTernal PERiod le 2 5 This command configures the internal integration gate to have a length of 10 milliseconds with five sub samples of the integrator output after 2 4 6 8 and 10 milliseconds SCPI provides for a long and short form for each command The short forms are indicated by the capitalized part of the command denotes a required argument denotes an optional argument Some commonly used commands are available from the root of the hierarchy as a shortcut as well as in their logical position in the structure For example CAPacitor 1 and CONFigure CAPacitor 1 are equivalent ways to switch in the large feedback capacitors on the four channels A number of commands are password protected to reduce the chance of changing them accidentally The commands only effective after the device has been rebooted if they have been enabled by first sending SYSTem PASSword 12345 Sen
40. V CAO5N module el POS O HVE LJ E INT HV o NEG 500 V CAOSP module To HVE POS A 5 INT HV NEG O 200 V CAO2N module al Pos O E HVE E E INT HV uN NEG 200 V CA02P module al HVE POS E T INT HV NEG o 1400 User Manual 1400_UM_090105 Page 67 of 104 PSI System Controls and Diagnostics 17 5 1 2 Signal bias HV options Installed option Sw1 2 JPR1 JPR3 No signal bias HV don t care e HVI don t care 400 V CA10N module N E NEG E O HVI INT HV POS 400 V CA10P module N E mv NEG O 0 i INT HV o POS 400 V CAOSN module N e e v NEG i l gt INT HV POS o 400 V CAOSP module N mv NEG H E E z INT HV POS l 200 V CA02N module N v NEG H lt INT HV POS 200 V CA02P module N Hvi NEG O H INT HV POS If no signal bias HV module is fitted then a shorting link should be installed between the PCB sockets corresponding to the HV output pins of the module This ensures that the isolated signal input section is connected to chassis ground potential 1400 User Manual 1400_UM_090105 Page 68 of 104 PSI System Controls and Diagnostics 17 5 1 3 Feedback capacitor options Changing the feedback capacitors requires specialized soldering techniques and can only be done in the factory The following information is for refer
41. VID a product identification PID and the unit serial number All 1400s have the same VID 0403 indicating the USB interface chip vendor FTDI Ltd and PID C589 indicating the 1400 product but have a unique serial number Microsoft Windows will recognize when a device with a new combination is connected for the first time and launch the Found New Hardware wizard The selection of files installed by the Wizard is guided by information in the file PTC INF There are two types of driver for the FTDI chip COM and DLL It is important not to let the wizard install the COM driver which it tends to do if you take defaults The PSI Diagnostic software requires the DLL driver The wizard should be run as follows The screenshots are from Windows XP The dialog boxes have different appearance on Windows Vista and the process is more automated 1 Don t let the wizard look for drivers on the internet Found New Hardware Wizard Welcome to the Found New Hardware SY Wizard Windows will search for current and updated software by looking on your computer on the hardware installation CD or on the Windows Update Web site with your permission Can Windows connect to Windows Update to search for software C Yes this time only C Yes now and every time connect a device No notthis time Click Next to continue 2 Select installation from a specific location 1400 User Manual 1400 UM_090105 Page 24 of 104
42. X tper 14 2 Gain calibration The calibration gain factors convert charge into ADC output and thus are the composite of the feedback capacitor size buffer amplifier gain and ADC gain The 1400 calibrates itself automatically on all channels by switching on the internal 500 00 nA current sources and making measurements with known integration period IMPORTANT There must be no signal current flowing into the inputs when the calibration is taking place because it will add to the calibration current and give an incorrect result This incorrect calibration would not be detectable by checking the internal calibration source readback but only by measuring a known independent current source Because background offset current can affect the gain calibration process itself the 1400 also makes a background measurement as part of the calibration cycle The measured background ADC difference is subtracted from the ADC difference measured with the calibration source on to get the net value that is equated to 500 nA The calibration factors are stored in the 1400 in EEPROM when a save calibration command is issued They are then loaded automatically on power up If there is no calibration available the 1400 will use a nominal calibration and the measurements will be of limited accuracy 1400 User Manual 1400 UM_090105 Page 57 of 104 PSI System Controls and Diagnostics 15 Setting the High Voltage The range and polarity of the high vol
43. _090105 Page 96 of 104 PSI System Controls and Diagnostics Incorrect port settings Try to connect with the htm file supplied with the unit Correct the settings Incorrect cable Make up a suitable cable See sections 9 and 16 1400 User Manual 1400_UM_090105 Page 97 of 104 PSI System Controls and Diagnostics 24 Maintenance The 1400 does not require routine maintenance There is risk of contamination which may degrade performance if the case is opened There are no user serviceable parts inside A CAUTION High voltages are present inside the case Do not open the case when power is applied The 1400 is fitted with a 1 1 A automatically resetting positive temperature coefficient PTC fuse in the 24 VDC input No user intervention is required if the fuse operates due to overcurrent The fuse will reset when the overcurrent condition ends 1400 User Manual 1400 UM_090105 Page 98 of 104 PSI System Controls and Diagnostics 25 Returns procedure Damaged or faulty units cannot be returned unless a Returns Material Authorization RMA number has been issued by Pyramid Technical Consultants Inc If you need to return a unit contact Pyramid Technical Consultants at support ptcusa com stating model serial number nature of fault An RMA will be issued including details of which service center to return the unit to 1400 User Manual 1
44. a 4 p 6 a 28 10 2 0E 12 e Ch1 ion chmbr Ch2 no signal 10000 msec 6 0E 12 5 0E 1 2 SS E E NS AS y 4 0E 12 4 3 0E 12 4 2 0E 12 4 1 0E 12 4 0 0E 00 A o ee 1 0E 12 200 400 600 800 1000 Ch1 ion chmbr Ch2 no signal Figure 38 Separation of a 5 pA signal from background Where there are known dominant noise frequencies in current measurements for example line voltage interference these can be suppressed by choosing an integration periods that is an integer multiple of the noise period For example 50 Hz or 60 Hz noise from the power line is present in most environments This can be completely removed in the 1400 by selecting the integration period as follows Noise frequency Integration period choices to eliminate noise 50 Hz 20 00 40 00 60 00 80 00 100 00 Kx 20 00 msec 60 Hz 16 67 33 33 50 00 66 67 83 33 100 00 K x 16 67 msec Very small charge package measurements should be optimized by synchronizing the integration carefully around the arrival of the charge This minimizes the amount of background offset current that is included in the reading Often the arrival of the charge is associated with an event 1400 User Manual 1400 UM_090105 Page 89 of 104 PSI System Controls and Diagnostics in the system which can be used to drive the external gate input of the 1400 to obtain the required synchronization 21 7 Summary Factor Typical noise
45. al source such as an ionization chamber are connected to the four inputs via individual triaxial cables In this example an additional electrode is biased by the auxiliary external output A gate signal generated by a remote timing controller for example triggers the 1400 to start measuring data Conductive Minimal length of unguarded signal core enclosure Inner guard screen at input bias potential Outer screen shields AC fields Signal source 0 p Signals Aux bias Gate in 24V in Figure 3 Schematic 1400 installation Refer to section 21 in this manual for general guidance on making low current measurements The 1400 should be located as close to the source of the signal as possible Long signal cables increase the chances of seeing unwanted signals and noise A maximum length of 3m is advised Longer cables may be used but the lowest detectable current will be increased 8 3 2 Signal cables Triaxial cable should be used terminated in triaxial connectors at the 1400 end according to the connector option that you specified Three lug triaxial connectors are standard on the 1400 with two lug connectors are available as an option The signal core and the inner guard screen are at bias potential which can be up to 400V The outer screen is at 1400 chassis potential The inner guard should be brought as close as possible to the point of connection to the signal source but should not be connected to
46. amp 1400 7 Address 7 on USB 00000743 nected Pending Communication SYSTem Properties Utilities Messages Sent Device Version Upload Application SAFEstate 1179676 4 04 _ Select hex file Checksum Errors 0 Reset Device Echo Errors 3 Timeouts AUTORECover FPGA Version 1 4 2 COMM TERM Reset Counters I_Last Error 9 27 44 PM CALIBRA y File name 1400 PIC 4_0A hex y Files oftype PSI Device Firmware hex v Figure 33 Selecting the hex file to load 1400 User Manual 1400 UM_090105 Page 84 of 104 PSI System Controls and Diagnostics _ PSI Loop Diagnostic v4 06 olx Actions Window Help Petey 00 A A 1400 7 Address 7 on USB 00000743 Communication SYSTem Properties Utilities Messages Sent SAFEstate Device Version Upload Application 1181990 E 4 0A PISA E e 7 E 18 complete Checksum Errors AAA FPGA Version aaa Soe ERM 1 4 2 Reset Device COMM CHECksum 4 Hardware Version Echo Errors EREET 3 3 50 Hz 1O Input Length Timeouts SERIALnumber 5 e E 0000054321 1O Output Length 26 COMMTIMEout Reset Counters 0 Last Error 9 27 44 PM CALIBRATIONSAVE 203 CommandProtected Figure 34 Upload in progress 1400 User Manual 1400 UM_0
47. anything at that end The outer screen should generally terminate on the grounded enclosure of the signal source 1400 User Manual 1400 UM_090105 Page 18 of 104 PSI System Controls and Diagnostics 8 3 3 Signal current path Figure 4 illustrates how the current you are measuring passes along the cable inner conductor to the 1400 input It effectively flows between the terminals of the input amplifier to the local floating ground due to the amplifier virtual earth then out to the case of the 1400 through the signal bias high voltage power supply If the supply is not enabled then it appears as an impedance of approximately 300 kohm The current then returns to the current source along the outer screen of the signal cable If you need to break the continuity of the outer screen for noise suppression reasons then you must ensure there is an alternative path between the 1400 and the signal source or you will see no current 1400 To Guard Current Outer screen source LAO ODl B gaw way Q A Eg LA Y Signal bias PSU Alternative return if outer screen is broken Figure 4 Path of measured current 8 3 4 Mounting orientation The 1400 may be mounted in any orientation Leave 100mm clearance at either end for mating connectors and cable radii The mounting should be secure and there should be as little vibration or movement as possi
48. arameter selects how many readings will be taken following initiate and triggering Infinite setting allows the 1400 to acquire data continuously until you abort or alter settings Data You can mask which channels are fed into the internal data buffer and set the maximum size of the buffer Calibrate 1400 User Manual Clicking the calibrate button causes the 1400 to execute its automatic self calibration routine using the precision 500 nA internal current source The gain values will be displayed upon completion You can save the calibration to 1400 EEPROM memory load a previously stored calibration or clear to the uncalibrated state There are two calibration memories labeled user and factory The intent is that the factory calibration is retained as a safety fallback whilst the user calibration can be updated at will However you are free to use them in any other fashion 1400_UM_090105 Page 34 of 104 PSI System Controls and Diagnostics The green LEDs alongside the gain factors indicate that the calibration is within allowed tolerance bands Note the external calibration function is no longer supported Calibration Current You can toggle the built in 500 nA calibration source with this button and control which channel it is directed to This provides a useful diagnostic function Reset You can alter the reset settle and setup times away from their default values Refer to sec
49. as soon as triggered Set integration period in seconds minimum le 4 s maximum 6 5e 1 s lt sub gt subsamples per period default 1 shortcut Query integration period shortcut Initiate single acquisition and fetch data when complete Read charge data lt integration period chargel charge2 charge3 charge4 over range flags gt Read current data lt integration period currentl current2 current3 current4 over range flags gt Read digitals bit0 2 reserved bit3 HV enabled bit4 external gate Read monitor voltage input ADC Read pressure input ADC Read temperature input ADC Do same READ as last defaults to charge if no defined last READ Status registers Operation register Questionable register 1 1400_UM_090105 Page 80 of 104 PSI System Controls and Diagnostics EVENt PRESet SYSTem COMMunication CHECKsum 011 TERMinal 011 TERMinal TIMEout lt timeout gt TIMEout ERRor FREQuency lt frequency gt PASSword lt password gt PASSword SAFEstate SAFEstate SERIAL number lt string gt SERIAL number VERSion TRIGger COUNt DELAY lt delay gt DELAY POINts lt number gt lINFinite POINts Not used System commands Communication settings Append checksum to all replies password protected O off 1 on Enter terminal mode
50. ay format 1400 User Manual 1400 UM_090105 Page 35 of 104 PSI System Controls and Diagnostics Try other channels and investigate the effect of changing the integration time and the feedback capacitor and of changing the display from current to charge If the calibration current is overrange the current reading is shown in red text 11 4 Device screen Click on the Device tab You can check the communication link status and verify the versions of the hardware and firmware On the right is the firmware update utility You can use this to download firmware updates hex files downloaded from the Pyramid Technical Consultants Inc web site i 1400 7 Address 7 on USB 00000743 0 x o a j Penang Error Device Communication SYSTem Properties Utilities Messages Sent SAPESute 3 Device Version Upload Application 1006923 4 0A Select hex file AUTORECover e i Checksum Errors 7 FPGA Version mo COMMTERM_ 1 4 2 Reset Device COMMCHECKSUM 10 Hardware Version Echo Errors FREQuency 3 3 q gt R _ 50 Hz 10 Input Length Timeouts SERIALnumber 2 0 0000054321 10 ind COMM TIME out Reset Counters 0 Last Error 9 27 44 PM CALIBRATIONSAVE 203 CommandProtected Figure 15 Device tab showing firmware update utility controls Communication The counters show details of the communications between the 1400 and its host You can click the Reset Counters b
51. ble at the 1400 and at the connecting triaxial cables Extremes of temperature temperature variation and humidity will all degrade measurements and must be avoided 1400 User Manual 1400_UM_090105 Page 19 of 104 PSI System Controls and Diagnostics 9 Getting Started Using ASCII Communication Before installing the 1400 in its final location and if it is the first time you have used an 1400 we recommend that you familiarize yourself with its operation on the bench You can check the unit powers up correctly establish communications run the internal calibration procedure and read the internal calibration current A CAUTION Do not touch the inner screen or pin triaxial signal input connectors while the unit is powered in case bias voltage up to 400V is present 1 Inspect the unit carefully to ensure there is no evidence of shipping damage If there appears to be damage or you are in doubt contact your supplier before proceeding 2 Connect 24 V DC power but no other connections The power LED should illuminate when the power is applied and the status and link LEDs will cycle through green orange and red see section 17 3 Make a connection to a PC serial port A three wire lead terminated in a six pin mini DIN male connector PS 2 mouse type and a nine pin D female is required When the connector is pushed home in the 1400 the optical LED should extinguish and the RS232 should illuminate Connecting to
52. channel SOURce 011 Turn on internal calibration source O off 1 on SOURce Query internal calibration source state RCL Recall the gains and zero offset currents from EEPROM SAV Store the gains and zero offset currents to EEPROM CAPacitor 011 Set feedback capacitor for all channels O small value 1 large value CAPacitor Query feedback capacitor setting CONFigure ACCUMulation 0111213 Accumulate charge across gate resets 0 do not accumulate 1 accumulate by interpolation 2 accumulate by no lost charge method 3 accumulate without correction for deadtime during resets ACCUMulation Query accumulation setting CAPacitor 011 Set feedback capacitor all inputs 0 small value 1 large value CAPacitor Query feedback capacitor setting and value in F GATe Configure integration gate EXTernal Configure external integration gating POLarity 011 Set external gate polarity external trigger only O high active 1 low active POLarity Query external gate setting INTernal Configure internal integration gating 1400 User Manual PERiod lt total gt lAUTO scale subsamp Set integration period in seconds or enable autoscaling lt subsamp gt subsamples per period default 1 PERiod Query integration period and subsamples RANGe lt amps gt subsamp Set a full scale current range by adjusting integration period for the selected
53. cs 1400 HyperTerminal DAR File Edit View Call Transfer Help Da 3 28 2 4 CALIB GAIN CALIB GAIN 1 2089e 00 1 2001e 00 1 1897e 00 1 2205e 00 READ CURR 1 0000e 04 1 4757e 10 A 1 8312e 10 A 2 1783e 10 A 1 4899e 10 A 0 READ CURR 1 0000e 04 0 0000e 00 A 0 0000e 00 A 3 6306e 11 A 7 4496e 11 A 0 READ CURR 1 0000e 04 S 1 4757e 10 A 3 6623e 11 A 3 6306e 11 A 7 4496e 11 A 0 CALIB SOUR 1 READ CURR 1 0000e 04 5 0003e 07 A 4 9994e 07 A 4 9997e 07 A 4 9994e 07 A 0 SYST PASSWORD 12345 CONF HIVO SIG MAX 100 CONF HIVO EXT MAX 100 CONF HIVO SIG VOLT 10 CONF HIVO EXT VOLT 25 RST Connected 1 41 23 VTS2 115200 8 N 1 Figure 8 Example Hyperterminal session 15 If you wish to explore the ASCII communication capabilities of the 1400 more fully refer to the commands list in section 19 You may also wish to try out the terminal mode which provides feedback from the I400 to every message you send not just query messages and is therefore more user friendly 1400 User Manual 1400 UM_090105 Page 23 of 104 PSI System Controls and Diagnostics 10 Software Installation The 1400 is supplied with software programs and drivers on a USB memory stick We recommend that you copy the files into a directory on your host PC 10 1 USB Drivers If you intend to use the USB interface you must install the appropriate drivers on your computer Each 1400 is identified on USB by a vendor identification
54. ctive per V t Charge injection from Cs Figure 22 No lost charge timing diagram The integration period tper is effectively extended over the complete integration cycle 13 3 Time Resolved Measurements 13 3 1 Standard Mode and FastMode The 1400 can operate in two data transfer modes according to the type of host system it is communicating with Standard mode The 1400 generates readings at the rate dictated by the integration time subsample count and reset parameters The host system collects these readings at the rate allowed by the host software and the communications link Any readings which are not collected before the next reading overwrites them are lost Standard mode communications can be by ASCII or binary messages with binary more efficient and thus faster The readings are translated to coulombs by the 1400 using the stored calibration FastMode FastMode is only available in combination with the Pyramid Technical Consultants Inc A500 real time controller It is automatically selected with the first initiate command for all running modes except all accumulation modes gated trigger mode and message trigger mode If you are 1400 User Manual 1400 UM_090105 Page 47 of 104 PSI System Controls and Diagnostics using the PSI Diagnostic host software there is a LED display on the Data tab which shows that FastMode is in use FastMode permits use of integration periods and subsample pe
55. d acquisition sequence Readings continue until either the programmed number of integrations is complete or the gate input falls rises again in which case the sequence terminates after the sub sample in progress Readings continue until the defined number of triggers is reached or the abort message is received External Gated The gate input drives the integrators directly A rising falling edge on the gate input causes the S2 switches to close The ADC converts at maximum rate When the gate input falls rises again the latest ADC reading is used together with the first to obtain the 1400 User Manual 1400 UM_090105 Page 51 of 104 PSI System Controls and Diagnostics measured charge and the integration time is recorded The maximum integration time allowed is 64 msec If you use a longer time the internal time counter will overflow and data will be incorrect Message A special one byte message on the communication link triggers the predefined acquisition sequence Readings continue until the defined number of triggers is reached or the abort message is received This trigger mode is only supported via the RS 232 and USB ports or via the A200 loop controller It is not supported through the A500 or A300 loop controllers ExternalStartHold not supported on the 1400 In all cases you can select infinite triggers and the acquisitions will continue indefinitely until you sen
56. d the abort command or reset the 1400 The external and gated modes require a physical signal via the gate input BNC They are the most appropriate modes to use when you require the minimum sub microsecond and most consistent delay between the trigger and the start of integration The sense of the logic is a software configurable parameter The gate input requires a TTL level and presents a TTL gate impedance To avoid spurious signals due to noise we recommend that you fit a 50 ohm terminator to this input if you are not using it If your trigger source is able to drive a 50 ohm load we also recommend this termination if you are using the input Message triggering provides similar performance to the external modes but with slightly greater delay In looped systems the loop controller knows the position of each device in the loop and arranges for each device on the loop responding to the trigger to delay its response according to its position in the loop so that all devices start their acquisitions at the same time 13 6 3 Illustrations of external triggers Figure 25 is a schematic example showing an external start trigger of a sequence of seven integrations Each integration includes three sub samples for a total trigger point count of 21 Data is of course gathered on each of the two channels A similar sequence could be started by a message trigger 1400 User Manual 1400_UM_090105 Page 52 of 104 PSI System Control
57. ding any other number as the argument of this command disables the protected commands again 19 2 3 1 ADDRESSING DEVICES SCPI does not provide specific commands for addressing multiple devices because this was handled by hardware in the original IEEE 488 1 specification The 1400 provides a simple mechanism for making any device on the loop the listener The device will remain the listener until another device is selected address Make device address 1 to 14 the listener Query which device is listener 1400 User Manual 1400 UM _090105 Page 75 of 104 PSI System Controls and Diagnostics 19 2 3 2 IEEE 488 2 MANDATORY COMMANDS CLS Clear Status Command Clear all event registers and the error queue ESE Standard Event Status Enable Command Program the Standard Event Enable register 8 bits ESE Standard Event Status Enable Query Query the state of the Event Status Enable register 1400 returns decimal value ESR Standard Event Status Register Query Query the state of the Event Status register 1400 returns decimal value IDN Identification Query Query the device identification 1400 returns manufacturer model number serial number firmware version OPC Operation Complete Command Set the Operation Complete bit in the Standard Event Status Register after all pending commands have been executed Not currently supported OPC Operation Complete Quer
58. ds Force incoming data to 7 bit ASCII Input Translation ASCIl Setup V Wrap lines that exceed terminal width Figure 7 Hyperterminal terminal settings 6 Type lt CR gt to query the active listener You should get the response 4 You are communicating successfully with the 1400 If you hear your computer s bell sound when you send the string the 1400 did not understand it probably because there was a typing error If the 1400 does not echo correctly either the terminal settings or the 1400 switch settings are likely to be wrong Check them and retry until you see the characters echo correctly If you make any errors while typing use the backspace key and re type from the error 7 Type calib gain lt CR gt The characters can be upper or lower case The 1400 will perform its internal calibration sequence 8 Type calib gain lt CR gt The 1400 will return the gain factors for the four channels 1400 User Manual 1400 UM_090105 Page 21 of 104 PSI System Controls and Diagnostics 9 Type read curr lt CR gt The 1400 will do a measurement and return the integration period it used and the measured current values for each of the four channels The current values should be close to background The default integration period on power up is the one that gives a one microamp full scale for example 0 1 msec for a 10 pF feedback capacitor 10 msec for a 1000 pF feedbac
59. e charge values by the integration periods The channels that are buffered are selected according to a data feed mask The fixed maximum amount of buffer memory is 200 charge values This can hold more measurement points if fewer channels are selected in the mask Setting the data points parameter to zero makes the 1400 use the whole available buffer memory The number of data points that this represents N 1 in figure 24 given the data feed mask setting in force can be queried for example with the DATa POINts command in the ASCII communications protocol The trigger count is a number that increments with each measurement trigger It is reset to zero by the initialize command It allows the data points recovered from the buffer to be correctly ordered and any missing data to be identified When the buffer fills then data buffering is halted It will also halt if the trigger point limit is reached Individual values may be read from the buffer by the buffer index from 0 to buffer points 1 If wrap is on incoming values continually overwrite the oldest value in the buffer The best way for a host computer to recover the measurements is with the data stream command This gets values starting with the oldest in the buffer and moving forwards each time it is called So long as the average rate of calling data stream is not lower than the incoming data rate no data points will be lost 13 6 Triggering and externally triggered acquisiti
60. ence only Installed option JPR1 Lo 10 pF o Hi 1000 pF ae 9 Lo 100 pF CAP Hi 1000 pF Lo 10 pF Hi 10000 pF m ad Lo 100 pF CAP Hi 10000 pF E 17 5 1 4 Pressure and temperature sense options Installed option JPR1 No pressure or temperature options installed O _0O Pres 0 Res Atmospheric pressure sensor installed A Pres O Oj Res Note the resistance thermometer input is read and displayed by the PSI Diagnostic host software even if no probe is connected The pressure sensor input is only read and displayed if the option is fitted and enabled with JPR1 The final position on JPR1 Res is reserved for future use 1400 User Manual 1400_UM_090105 PSI System Controls and Diagnostics 18 Communications Interfaces The 1400 is a member of the PSI range of devices More details of PSI device interfacing options can be found in document Pyramid Technical Consultants document PSI_AN_060505 Versatile Communications and Control for Scientific and Engineering Applications The unit is provided with three hardware interfaces RS 232 USB and fiber optic The RS 232 and USB interfaces are intended for simple direct connection to PCs with no other equipment necessary The fiber optic interface provides greater speed excellent noise immunity and allows multiple devices to be connected i
61. evice addressing is performed using the special command Addressing is only necessary for devices linked by a fiber optic loop but A device is made the listener when the host sends FADDRESS For example 4 will make the device with address 4 the listener You must ensure that all devices on the same communications channel have unique addresses All subsequent commands sent without address will be listened and responded to by device 4 only The host message asks who the listener is The command can be sent as a compound message such as 3 IDN 19 2 2 Status registers The 1400 implements the IEEE 488 2 status register method Each of the registers is masked by a corresponding enable register It is recommended that you set all the enable registers to all 1 s The host software should use the STB command to watch for changes to the status of the 1400 and then ESR STATus OPERation CONDition or STATus QUESTionable CONDition as appropriate to recover the details from the relevant register 1400 User Manual 1400 UM_090105 Page 73 of 104 PSI System Controls and Diagnostics Questionable Status
62. ge amplifier output voltage cannot exceed its voltage supply rails It is necessary to reset the integrator periodically at a rate determined by the average input current and the size of the feedback capacitor After the defined integration period tper Switch Sw2 closes to short the feedback capacitor and release the charge so zeroing the integrator ready for the next cycle 1400 User Manual 1400 UM_090105 Page 39 of 104 PSI System Controls and Diagnostics The reset time needs to be sufficient to completely clear the accumulated charge through the FET on resistance and thus depends upon the size of the feedback capacitor There is also a short settle time allowed after opening Sw2 to start the integration before the start ADC reading is taken to allow transients to die away A further time associated with the reset called the setup time accounts for the fact that the ADC conversions are not generally exactly aligned with the end of the specified integration period 12 2 1400 Circuit Overview Four identical gated integrator channels operate in an isolated circuit section which can be biased up to 400V from ground with the built in high voltage supply Parallel ADCs digitize the charge values and the numeric values are managed by a microcontroller FPGA combination which handles all measurement timing control calibration data conversion and communications to the user s host computer system Communications can be via RS 232 US
63. ified in your order 1400 User Manual 1400 UM_090105 Page 10 of 104 PSI System Controls and Diagnostics 5 Optional Items 5 1 Power supplies PSU24 36 1 24 VDC 36W PSU universal voltage input plug receptacle for standard IEC C8 two pin socket with output lead terminated in 2 1mm threaded jack PSU24 45 1 24 VDC 45W PSU universal voltage input plug receptacle for standard IEC C14 three pin socket with output lead terminated in 2 1mm threaded jack 5 2 Signal cables and cable accessories PCBOT20PCB 80 Cable triax plug to triax plug input 3 lug 3 m PCAOT20PCA 80 Cable triax plug to triax plug input 2 lug 3 m PCB2T20P1A 80 Cable triax plug 3 lug to BNC coax plug input cable 3 m Outer screen and signal core connected through inner guard screen floated at BNC end ADBJ77 E2 PL20 Adaptor triax 3 lug jack to BNC plug Guard not connected through ADBJ20 E2 PL75 Adaptor BNC jack to triax 3 lug plug Guard not connected through RF175 1 Dust cap 3 lug triax RF175TL 1 Dust cap 2 lug triax SHV to SHV cable 3m Remote temperature sensing thermistor cable assembly terminated in four pin Lemo type OB plug also available as part of 1400 option TP 5 3 Data cables RS 232 6 pin DIN male to 9 pin D sub male cable 3m 1400 User Manual 1400 UM_090105 Page 11 of 104 PSI System Controls and Diagnostics Fiber optic cable pair 5m 5 4 Fiber optic loop A100 RS 232 to fiber optic adap
64. ill be lost 1400 User Manual 1400_UM_090105 Page 37 of 104 PSI System Controls and Diagnostics 12 Principle of Operation 12 1 Gated Integrators The 1400 uses the gated integrator method This is a particularly effective technique for measuring small amounts of electrical charge The charge accumulates on a small low leakage capacitor in the feedback loop of an operational amplifier with the result that the voltage at the amplifier output is the integral of the current that flows into the input figure 16 FET Sw2 o o Ci A MN ge t t ST FET 1 Swi Po fiat fb Figure 16 The basic gated integrator circuit Integration starts when FET switch Sw2 is opened The current into the input can be negative or positive The voltage at the output of the amplifier is sampled and digitized by an ADC Calibration with a stable accurately known test current allows variables such as the exact size of the feedback capacitor buffer amplifier gain and ADC gain to be compensated in a single gain factor At any time t after the start of the integration the accumulated charge is thus given by d meas K ADC a ADC tap where k is the gain factor The data can also be presented as an average current in the time interval between the readings because that interval is known accurately _ k ADC ADC meas t start As the integration proceeds this measure of the average current achieves inc
65. ime of order which provide greater current compliance Q o Unavailable A Q o Operating region T 2 oO Oo E S 600 o o 2 c o gt O Le o o o 50 100 150 200 250 300 350 400 Voltage setting V Figure 29 Current compliance of the high voltage supplies Positive supplies source conventional current and negative supplies sink conventional current A bleed resistor fixed load is connected to each high voltage supply output which drains 40 uA at maximum voltage Transorb protection devices prevent the absolute value voltage at the output going more than 40 V signal bias or 80 V external high voltage above the maximum 1400 User Manual 1400 UM_090105 Page 58 of 104 PSI System Controls and Diagnostics rating However these devices are not designed to pass large currents indefinitely so you should be careful not to overdrive the outputs with other power supplies or with charged particle beam strike currents A CAUTION Do not connect external power supplies to the 1400 signal inputs or external high voltage output that will drive the built in supplies away from the voltages they are trying to regulate or you may cause damage to the 1400 A CAUTION Do not connect the 1400 signal inputs or the external high voltage output to electrodes in a system that will be subject to direct strike by high energy high current charged particle beams that will drive the built in supplie
66. ime setting Drift lt 0 5 over 12 hours External accuracy 0 25 of full scale charge current for the selected capacitor and integration time Signal input bias PSU 0 to 400 V programmable 10 bit resolution 1mA max option f Noise and ripple lt 0 1 of full scale Auxiliary PSU option 0 to 1000 V programmable 10 bit resolution 1mA max Noise and ripple lt 0 1 of full scale External gate 0 45 V TTL level 2 kohm input impedance Power input 24 VDC 2 V 350 mA Case Al alloy 6060 Al Mg Si and B4130 Al Si black powder coat SBS elastomer end flange seals Case protection rating 1400 User Manual The case is designed to rating IP43 protected against solid objects greater than 1mm in size protected against spraying 1400_UM_090105 Page 14 of 104 PSI System Controls and Diagnostics water Weight 1 64 kg 3 6 1b Operating environment 0 to 35 C 15 to 25 C recommended to reduce drift and offset lt 70 humidity non condensing vibration lt 0 1g all axes 1 to 1000Hz Shipping and storage 10 to 50C environment lt 80 humidity non condensing vibration lt 2 g all axes 1 to 1000 Hz Dimensions see figures 1 and 2 FIBER OPTIC TX FIBER OPTIC RX STATUS LEDs OXmit O Status ORev OLink Mode Address y E E RS 232 o E 4X SIGNAL I
67. is the start bit followed by seven bits encoding a character from the ASCII character set A full command from the host to the 1400 comprises as many ASCII characters as needed to form the message terminated by the LF 0x0A character The 1400 will not start to process a command until the OxOA character is received The list of valid commands is listed in the next section If the communications is being handled in a terminal session the terminal program should send CR Ox0d before the LF to get a legible display The CR is ignored by the command interpreter in the 1400 The 1400 generates a reply to every message from the host when it is the listener The first byte of its reply will always be a single non printing character The first character is ACK 0x06 when the command has been successfully executed with no errors Responses to host commands with a will then have the required data terminated with the CR LF sequence If the host is not requesting data no no other bytes will be transmitted after the ACK If the 1400 generates an error when executing the host command it will transmit a single BELL 0x07 as its response A computer running a terminal program will therefore beep when the 1400 cannot execute a command for example due to incorrect syntax A more interactive terminal mode can be selected which modifies this behavior to make the 1400 more user friendly when it 1s being driven from a terminal program D
68. it Please contact your supplier or Pyramid Technical Consultants Inc before attempting any work inside the unit The settings of internal switches and jumpers is given here for reference only The locations are shown in figure 31 together with the programming connectors for the PIC microcontroller and FPGA steanenennenes CU 2 Figure 31 Internal switch and jumper locations The screening cover has been removed for clarity 17 5 1 HV option selection The installed external auxiliary HV option is defined by the setting of SW1 1 the HVE section of JPR1 and the setting of JPR2 The signal bias internal HV option is defined by the setting of SW1 2 the HVI section of JPR1 and setting of JPR3 The settings are summarized in the following tables SWI sets the polarity JPR1 sets the range and HV module type JPR2 and JPR3 also set the polarity for the voltage monitor readback The HV modules are socket mounted and can be exchanged in the field by suitably trained technicians 1400 User Manual 1400 UM_090105 Page 66 of 104 PSI System Controls and Diagnostics 17 5 1 1 External HV options Installed option Sw1 1 JPR1 JPR2 No external HV don t care a don t care o 0 1000 V CAION module o POS i o HVE o INT HV NEG 1000 V CA10P module el HVE POS z INT HV a NEG O 500
69. k capacitor and so on If you repeat read curr lt CR gt a few times you should see the readings change due to background noise 10 Type calib source 1 lt CR gt This turns on the internal 500 nA calibration currents to each channel Type read curr lt CR gt to read this current You should see values very close to 5 0e 7 A 11 Type syst password 12345 You are now in administrator mode and able to alter some important parameters The 1400 will leave administrator mode when it is reset or the power is cycled 12 Type conf hivo sig max 100 This establishes 100V as the maximum signal high voltage bias you can set Type conf hivo ext max 100 This does the same for the auxiliary HV supply These values are retained indefinitely in EEPROM until you set new values 13 Ensure nothing is connected to the signal inputs nor the external HV bias output If your 1400 has the external bias HV option type conf hivo ext volt 25 lt CR gt This will turn on the high voltage at 25 V and the HV on LED will illuminate If your 1400 has the signal bias HV option type conf hivo sig volt 10 lt CR gt This will turn on the high voltage at 10 V and the HV on LED will illuminate 14 Type rst lt CR gt to reset the 1400 Your unit is functioning correctly and is ready to be integrated into your system 1400 User Manual 1400_UM_090105 Page 22 of 104 PSI System Controls and Diagnosti
70. le on individual 1400s depend upon the options included Signal bias HV output External auxiliary HV output Atmospheric pressure built in sensor Temperature external resistance thermometer probe Monitor input available for measuring any external parameter that can be presented as a 0 to 10 V signal These parameters are all digitized at 10 bit resolution 12 3 Reset Settle and Setup Times The frequency at which new complete integration readings are generated is es ACA oy te Ft ee reset settle setup update where treset 1s the time that the integrator reset switch is kept closed tser1e is the further time for transient effects to clear before the ADC captures the value corresponding to the start of the integration period and tsetup 18 a time allowed to compensate the fact that ADC samples cannot occur precisely at the end of the integration period 1400 User Manual 1400_UM_090105 Page 41 of 104 PSI System Controls and Diagnostics tper can be from 100us up to 65 seconds set according to the signal level The live time proportion is given by per Matbaa t leatt reset settle setup The integrators have the choice of two feedback capacitor values under software control All four channels are switched together In combination with the choice of integration time this allows a wide dynamic range of currents to be measured The default reset settle and setup times for the standard ca
71. ls and Diagnostics _ k ADC ADC i start measInterim Nt sub In current reading mode the division by time to give current values is performed in the 1400 Note however that values stored in the ring data buffer are always charge see section 13 The selection of feedback capacitor and integration period determines the maximum current that can be measured _ 10C Lnax 7 e Commands to the 1400 that return current readings also return the integration period in seconds and a bitwise overrange byte that flags any channels where the reading has gone overrange ADC value greater than 95 of full scale The lower four bits indicate overrange positive and the upper four bits indicate overrange negative LSB Ch1 overrange ve Ch2 overrange ve Ch3 overrange ve Ch4 overrange ve Ch1 overrange ve Ch2 overrange ve Ch3 overrange ve MSB Ch4 overrange ve The deadtime composed of setup reset and settle time components while the integrators are being reset does not generally affect the integrity of the current measurement The only exception would be a case where a significant frequency component of the signal happened to coincide closely with the integration cycle This can be checked and avoided if necessary by altering the integration period 13 2 Charge Accumulation Applications such as radiation dosimetry often require the total charge to be accumulated so that a process can
72. ly to the feedback capacitor switches Sw2 The switches open on the specified edge remain open while the signal is maintained and close again when the signal returns to its original state Settle time is allowed as usual after the gates open before the start ADC reading is taken Sub sampling is not possible for gated acquisitions 1400 User Manual 1400 UM_090105 Page 54 of 104 PSI System Controls and Diagnostics i t Gate t settle V t ADC start Figure 27 Illustration of a gated measurement 1400 User Manual 1400 UM_090105 Page 55 of 104 PSI System Controls and Diagnostics 14 Calibration and background offset current correction Taking accurate current or charge measurements with the 1400 require accurate gain factors k for each channel and consideration of the background offset current 14 1 Background offsets Consider an integration cycle as shown in figure 28 The voltage presented to the ideal ADC comprises the integrated signal V signal_voltage the integral of any net background offset current Vodg current and a voltage pedestal Vorrser due to amplifier offsets and the offset of the ADC itself In practice these unwanted offsets will be much smaller than the signal and may be negative or positive relative to the signal but they must nevertheless be managed correctly to get maximum accuracy at the lowest currents and charges ADC l V
73. mooomommssssssmms 20 Software Installati On AA TAS 4 ERY BT aAA EEA AE PR PB ted 24 1400 User Manual 1400_UM_090105 Page 2 of 104 PSI System Controls and Diagnostics Installing the PSI Diagnostic Program oooonnccicnnononannnnnnnnonanonnnonnnnnnonnnonnn cone cn neon ron n enano nan enn nena e nnn enn nr acen nec ne cn nccnnconss 27 Getting Started using the PSI Diagnostic Program esseseessesesoessesoesoesessossessossesoesessossesoessesoosoesessossessessoesesssssess ZO Connecting to the 1400 oi pta ii odiar epica cess Apadrina 28 AE 14 A ES ARTO 31 SELUP SCLC it di A A AD ce suse cp ieee ee aN dein A EEE E S E eSEE PREE ASEE 33 AA A A cuieassaanadipsbenssqsdainadevadeedsasbaneadusibocbesdaaeaaseasacagcaubossaanaianibensacs 36 Principle of Operation cccscsssssssscsscsscsscescsssesssssnssccsssscescsssnsssssnessessseosssssnsssssnesessnessossessessssssessssscssessessosesseo DO Gated Integrated 38 TIERNA A AN 40 Reset Settle and Setup Times scccccesccesecesecsseesseessesseesseessensecesecesecaecaecaaeaeceaecaaecaaecaeeeaeeeaeeeseeeeeneeseeeeeeeseenaeenes 41 E Making Measurements ccmoocoonoconccnnccnncnnconnononononononncc sosoo sapesse orosei esros nsise sasore oeseri Saraso cono cono nono norc ano nro noo DD Continuous Current MeCAsurement ccccccsscceseceessecsenceensecsscecssecesacecsseceeaeecssecesaeecsaeeeeaeecsaeceeaeecsaeceeaeecaeeeeaeecnaeeesaes 43 Charge Accumulation a
74. mum allowed is 65535 bytes Couple Selecting AC coupling removes any DC component from the graphic display only Mode You can graph the data as a strip chart or a bar chart histogram You can also display the numerical derivative of the readings difference between successive readings 1400 User Manual 1400 UM_090105 Page 32 of 104 PSI System Controls and Diagnostics Run The Run control toggles whether data is accumulated into the buffer It does not have any effect on the data being generated by the 1400 Notice that there are three subsidiary tabs under the Data tab You have been looking at the default labeled current The two other subsidiary tabs display beam position monitor readout data This will be described in more detail in section 22 11 3 Setup screen Click on the Setup tab Here you can adjust measurement parameters such as integration period feedback capacitor set the auxiliary high voltage and use the built in calibration facility a 1400 7 Address 7 on USB 00000743 El x Comms Herre lt Connected Pending Error Setup CONFiguration Signal Bias TRIGger CALIbration Calibrate Clear Integration Period Max 400V to 0 V Source gt as pchanne Internal E Interna go I2 930 1 000E 004 v s 400 v E c External Gate Polarity current A 5 0000e 007 _ Ri o y EDIS Set Value HA i Cal Current 500 nA 1 000E
75. n externally triggered Dynamic range 0 1 pA to 100 uA with standard capacitors Built in calibration check current sources feeding each channel RS 232 USB and fast fiber optic serial interfaces built in Selectable baud rates Can be operated in a fiber optic serial communication loop with up to thirteen other devices 100BaseT Ethernet available through the A300 and A500 interfaces ASCII and binary serial data formats External thermistor temperature input and integrated atmospheric pressure input options Input bias option up to or 400 VDC Auxiliary HV output option up to or 1000 VDC 1400 User Manual 1400 UM_090105 Page 13 of 104 PSI System Controls and Diagnostics 7 Specification Inputs Four independent parallel Integration time Adjustable 100 us minimum 65 s maximum Input noise current lt 100 fA rms 1 fA rms per pF input load 0 1 second integration 10 pF capacitor O V bias Input background current lt 100 fA at 0 V bias 25 C for 8 hours after nulling lt 300 fA at 0 V bias 35 C after for 8 hours after nulling excluding external background current sources Stability Output drift lt 5 ppm C hour Digitization 16 bit over 10 V integrator output range 250 kHz Four ADC channels Linearity Deviation from best fit line of individual readings lt 0 1 of maximum current or charge reading for given feedback capacitor and integration t
76. n LED Data being received by the unit 1400 User Manual 1400 UM_090105 Page 64 of 104 PSI System Controls and Diagnostics 17 4 7 Status Red Green LED This LED indicates a variety of internal states as follows Alternating red orange green off Unit powering up Alternating green orange Off Unit idle not measuring Orange Waiting for trigger or resetting integrators Green Integrating Red Error Downloading program from host 17 4 8 Link Red Green LED This LED indicates a variety of communication states as follows Alternating red orange green off Unit powering up Off No connection since last power up Alternating green off Unconnected Alternating orange off Unconnected unit has gone to the safe state Green Connected Red Fatal communications error Fast alternating green orange Boot state waiting start command or code download 1400 User Manual 1400_UM_090105 Page 65 of 104 PSI System Controls and Diagnostics 17 5 Internal switches and jumpers There are no user serviceable parts inside the 1400 We do not recommend that you open the case because of the risk of damaging the components or contaminating the highly sensitive current measurement circuits There are internal switches and jumpers that are configured at the time of manufacture to reflect the configuration of the particular un
77. n a looped topology It requires a fiber optic adaptor or loop controller device to connect to the host computer The fiber optic interface is well suited to large systems and experiments Only one interface is in use at any time Selection of the active interface is according to the cables that are connected Cable connected Interface selected USB RS 232 None x USB x x USB x RS 232 x Fiber optic Interface speed and protocol is selected by the mode switch The fiber optic interface can run up to 10 Mbps and the RS 232 up to 115 2 kbps The USB port always runs at 3 Mbps irrespective of the mode switch position The following table summarizes the interface selection and protocol that is active for all possible connector and mode switch configurations The most common selections are shown in bold 1400 User Manual 1400 UM_090105 Page 70 of 104 PSI System Controls and Diagnostics Cable connected Interface Protocol selected by mode switch setting selected USB RS None 0 1 2 3 4 gt 6 7 8 9 232 x USB BIN8 BIN8 BIN8 BIN8 BIN8 ASC8 ASC8 ASC8 ASC8 3M 3M 3M 3M 3M 3M 3M 3M 3M x x USB BIN8 BIN8 BIN8 BIN8 BIN8 ASC8 ASC8 ASC8 ASC8 3M 3M 3M 3M 3M 3M 3M 3M 3M Xx RS 232 22 BIN8 BIN8 BIN8 ASC8 ASC8 ASC8 ASC8 115k 57 6k 19 2k 115k 115k 57 6k 19 2k x Fiber BIN9 BIN8 amp BIN8 B
78. nita A a A A A ARN REA 44 ING dead time COLE AA sansa Eaa a a a aa EE Eaa EARE EAE a E Ea EESE EEan ntbhedetebevere 45 Reset time interpolations us piba 45 No lost charge techii que coi e 45 Time Resolved Measurement tania 47 Standard Mode and FastMode oi ccssscsseissessssssessciesthsshasrousedadssasbesssosaeesdsescssecbouessadsasesapsbepdsebashessasvensbdeastesees sees 47 TUNE TES AE ita iS 48 Data Readout and BUM A Rem a Hea A ee ds ee eee et 49 Data O r eS AGGIE Ri AE RE Gi Ala a A a A a ct 49 Data butter anid data feed Mask oi A e 50 Triggering and externally trig gered ACQUISITIONS sssecesessesseseeeesecseeeecuseesceseecesecasesecuaeeecsasesesaecseesecuaeeeenaseneeas 5I Triggering trigger points and measurement timMing eeeeeeseseteresesrstsrtrtsretsrtstritttessesettettststsresteteeretsetessrsesete 51 Trepet SOULCES i minea i A tt 52 Tlustrations of external IES A E OEE eid SA 53 Calibration and background offset current correctiON ocoomommmsmsmsmsmms D BaCkgrOUNd OS CIS sd a dd A ds dest Ss 56 Cam COLD ALL ON A ia TEE EEE eas SN a ee id 57 1400 User Manual 1400 UM_090105 Page 3 of 104 PSI System Controls and Diagnostics x Setting the High Voltage isicssccsssvecsvessccscscestsscsssasscessonsseesenascasssessooss ovnsecedeadsonssesssesesdsses sus sussessaeseadsonssenstacechoousssnscese DO A sonedsossebsasssteasedessceessesseasscceesnsssesdboses E OAE i Front panel CONNEC CLOTS o 2is ce
79. ns USB type B female 16 2 3 RS 232 communications Six pin mini DIN socket PS 2 mouse keyboard type 4 5 6 n c Pin 3 Gnd Pin 2 Rx E Pin 1 Tx External view on connector solder side of mating plug The socket incorporates a sensor switch that allows the 1400 to detect that a plug has been connected 16 2 4 Fiber optic communications ST bayonet To mate with ST male terminated fibre optic cable Transmitter Receiver light gray dark gray N AN Take appropriate care when making ST connectors If there is a key on the central body of the ST plug must align with the keyway on the top of the socket on the 1400 before the plug can be pushed home The outer shell of the plug can then be rotated while pushing against the spring pressure to engage the bayonet 1400 User Manual 1400 UM_090105 Page 61 of 104 PSI System Controls and Diagnostics 17 Controls and Indicators 17 1 Front panel controls None 17 2 Rear panel controls RS 232 Optical Xmit Status Rcv Link Input Address 24V 500 mA PSI 3M 115K 57 6K 19 2K Binary p 3 4 Figure 30 Rear panel showing controls and indicators 17 2 1 Mode switch 10 position rotary switch setting communications mode Binary protocols are used for highest data rates by Pyramid Technical Consultants host systems The fiber optic link can run up to 10Mbps the USB up to 3 Mbps and the RS 232 up to 115 2bps The ASCII protocol is provided for
80. nts The integration method is inherently good at averaging noise Very low current currents generally require the smallest available feedback capacitor and the longest practicable integration time to build up a readily measurable voltage For example a 1 pA current integration on a 10 pF feedback capacitor requires 10 seconds to develop 1 V Background offset noise is also integrated of course and cannot be distinguished from the signal This sets the ultimate detection limit The plots in figure 38 illustrate how a 5 pA signal from a small ionization chamber becomes clearly distinguishable from a reference background signal and the noise reduces as the integration period is increased from 1 msec to 100 msec to 10 000 msec 1400 User Manual 1400_UM_090105 Page 88 of 104 PSI System Controls and Diagnostics 1 msec 2 0E 10 1 5E 10 4 ton a e be oa 5 0E 11 J a oe lt o v 09 mo mo pon a 0 0E 00 4 onsss 0 s0 mono e5 sap eneee 4 of 5 0E 11 9 ES 0 d2 di i 0 04 a lt 0 06 yoo vo 0 08 ve ree 01 1 0E 10 a 1 5E 10 e Chi ion chmbr Ch2 no signal 100 msec 7 0E 12 60E 124 g tr rd A A aaa A 5 0E 12 40 e 0 er te to ee fe de e 4 0E 12 de ae 50 ee 3 0E 12 2 0E 12 1 0E 12 o on a o o i o o of oo 4 o o i om 0 0E 00 a ae a ee A RL e 1 0E 12 9 a 2
81. nts to infinite measurements will continue indefinitely following the start event If you are in internal triggering mode the start event is generated internally The sequence therefore starts immediately after you send the initiate command The 1400 keeps count of the number of trigger points n following the start event and this number is used to determine the time of any measurement relative to the start of the sequence ty n t t settle Eo T ar E 0 e as boset g leii sub sub where Nsu is the number of subsamples per integration The formula simply reflects the fact that you always start with a settle time followed by an integration with a number of sub samples then followed by the reset sequence 13 6 2 Trigger sources There are several potential trigger sources and modes The gate polarity ie whether rising or falling edges cause the stated responses depends on the gate polarity parameter Internal Auto run The start event is generated internally by the 1400 once the initiate message is received Readings continue until the defined number of trigger points is reached or the abort message 1s received External Start A rising falling edge on the gate input starts a predefined acquisition sequence Readings continue until the defined number of trigger points is reached or the abort message is received External Start Stop A rising falling edge on the gate input starts a predefine
82. ons 13 6 1 Triggering trigger points and measurement timing Every measurement sequence recorded by the 1400 is a result of a sequence of triggers The sequence is started either internally or as the result of an external event You preset all the relevant parameters such as feedback capacitor integration period number of sub samples and type and number of triggers Then initiate the measurement The measurements only starts however when a trigger is detected 1400 User Manual 1400_UM_090105 Page 50 of 104 PSI System Controls and Diagnostics As an example say that you have requested ten trigger points four sub samples per integration and ExternalStart trigger mode looking for a high logic level on the BNC input The initiate command primes the 1400 but it will then wait until the trigger start event is detected The status LED will be orange in this waiting state When the gate input goes high the measurement sequence will start The status LED goes to green Four trigger points occur in the first integration period from the four sub samples four in the second integration and then the requested total of ten is reached halfway through the third integration Measurements stop being recorded and the status LED turns off Note that the analog integrators continue to run even after the measurement has been completed until you send the abort or initiate commands or new parameters are sent If you set the number of trigger poi
83. pacitor choices are Cm treset tsettle tsetup 10 pF 25 usec 20 usec 5 usec 100 pF 25 usec 20 usec 5 usec 1000 pF 25 usec 20 usec 5 usec 1400 User Manual 1400 UM_090105 Page 42 of 104 PSI System Controls and Diagnostics 13 Making Measurements 13 1 Continuous Current Measurement The 1400 can make a continuous reading of the current on its four inputs In this mode it behaves like a sensitive current to voltage converter The input current can be positive or negative A positive reading represents conventional current flowing into the 1400 A negative reading represents conventional current flowing out of the 1400 WAR VIO i t Sw2 ee se ee s r s per Vit Figure 19 Timing diagram for continuous current monitoring The deadtime for setup reset and settle t r s is shown relatively large Repeated integrations of the specified period are made Each integration yields start and end ADC values plus interim values from any sub integration sampling that has been requested The final measured current value for one integration is given by k ADC ADC yar meas t per where k coulomb bit is the stored calibration factor for that channel with the feedback capacitor in use The interim current value for the Nth sub integration interval N 1 2 with ADC value ADCn is 1400 User Manual 1400 UM_090105 Page 43 of 104 PSI System Contro
84. r the buffered data Data If you have the options for temperature probe atmospheric pressure sensor signal bias voltage or external bias voltage the readback values are displayed here If no temperature probe is connected the displayed value will be meaningless and should be ignored The probe connector also has a general purpose analog voltage input and its value is also displayed Y range This controls the vertical scaling of the data plot It can be automatic or various fixed proportions of the full scale of the range in use X time This controls how fast new points are added to the data plot This is generally limited by the speed of your PC If the averaging time has been set to a large period then this will override the update rate you set here because new data is only available at the rate determined by the update rate Buffer The PSI Diagnostic collects data coming from the 1400 as fast as it can into a buffer If the 1400 rate set by the integration time and the communications channel bandwidth is relatively low then every data point is logged Otherwise some readings will be lost but you can see this because every reading gets a trigger count and missing values are evident The buffer contents can be cleared with the Clr button or can be written to a csv file The buffer is also cleared by a new initiate command The kB and Buffer indicator show how much data is currently in the buffer The maxi
85. reasing signal to noise ratio as more charge is accumulated and the low pass filtering roll off due to the increasing integration time moves to lower frequency 1400 User Manual 1400 UM_090105 Page 38 of 104 PSI System Controls and Diagnostics The inherent integration is very effective in reducing noise being in effect a rectangular low pass filter with 3dB response at 0 44 t Hz and zero response at N t Hz N 1 2 3 Known dominant noise frequencies for example line voltage interference at 50 Hz or 60 Hz can be completely suppressed by choosing tper 1 50 or 1 60 seconds or integer multiples thereof Readings are available at times n tsu during the integration where n 1 N with N the number of sub samples requested in the integration period tper and tsub tper N Figure 17 illustrates how a portion of the input waveform is integrated by the opening of Sw2 ADC readings are taken for the sub samples with ADC tar being subtracted from each subsequent sample to produce a charge reading E a Open Closed i t Sw2 V t ADC N ADC n ADC ADC 0 ADC start eee nt sub l_ _ __ A gt gt t per Figure 17 Data acquisition timing diagram The plots are from the top illustrative input current waveform integrator gate Sw2 state integrator output with ADC sample points shown ADC readings Integration cannot proceed indefinitely because the char
86. riods down to 100 usec FastMode communications are in the form of raw 16 bit data The application of the calibration and translation to physical units is performed by the A500 The 1400 on board memory can store up to 50 four channel readings These are guaranteed to be contiguous even at the shortest integration and subsample periods Note that there will be deadtimes for each integrator reset however If you wish to capture a single shot event with no breaks in the data then this is still possible by using multiple subsamples in a single integration which encompasses the event Up to 256 subsamples can be used per integration The full ADC resolution is effectively shared between the subsamples You must also take care that the integrator does not overrange during the event In addition to the 1400 on board storage the A500 can store over 500 000 readings These will be contiguous if the communications between the 1400 and the A500 can keep up with the data generation rate This in turn depends upon the available bandwidth on the loop that services the 1400 13 4 Time resolution There is an inevitable compromise between the ability to resolve time structure in a current waveform and signal to noise ratio The 1400 naturally averages and thus suppresses high frequency components in the signal Where the signal to noise ratio is relatively large however data from sub integration sampling allows the details of the rise of the output voltage
87. rrange states of the channels Integration period gt t EE i 1 a2 2 i2 g2 l a3 i3 FETCh CURRent g3 a4 i4 p LL trigger DATa FEEd 1010 buffer index trigger count t t t t t t cl cl cl cl cl cl c3 c3 c3 c3 c3 c3 o r o r o r o r o r o r Tea 2 1 0 gt N N 1 N 2 lu k 2 k 1 k gt k N k N 1 k N 2 lt DATa STREAM DATa VALue N 1 1400 User Manual 1400 UM_090105 Page 49 of 104 PSI System Controls and Diagnostics Figure 24 1400 data flow The feed mask is set to pass data from channels 1 and 3 The contents of the temporary buffer can be read out at any time by FETCh commands If the fetch is for current as illustrated then the charge values are divided by the time to give four currents il 14 If the fetch is for charge no division is performed The alternative READ command causes an initialize canceling any acquisition in progress then does a fetch when the acquisition has triggered and is complete 13 5 2 Data buffer and data feed mask A ring data buffer in the 1400 allows data to be stored in the unit so that the host does not need continuously to keep pace with the data rate The values passed into the buffer include a trigger count the integration period the measured charges and the over range flags byte If you want to present the data as current samples then it is a simple matter to divide th
88. rt at once Otherwise the acquisition will start when the starting trigger is detected The number of readings in the initiate in progress is displayed in the Triggers box The LEDs indicate whether a measurement is in progress whether triggers are being detected and the state of the external gate input whether or not this is being used to trigger measurements Abort This stops an acquisition in progress Current charge You can display the 1400 reading in pA nA uA or amps or pC nC uC or 1400 User Manual 1400 UM_090105 Page 31 of 104 PSI System Controls and Diagnostics coulombs The check boxes determine whether the data is displayed The integration time in use is displayed in seconds If you have set up the 1400 to measure the output of a quadrant or dual electrode beam position monitor the results will be displayed Averaging You can set up data averaging by the PSI Diagnostic to make a fluctuating value easier to read This is in addition to the data averaging done by selection of the integration time The filter is only applied to the numeric display not the graphic nor the buffered data The Reset button clears past readings from the filter Zero The PSI Diagnostic will capture the latest reading and subtract it from all subsequent readings 1f you click the Zero button Pressing Clear stops this The subtraction is only applied to the numeric display not the graphic no
89. ry The address switch can be set to anything between 1 and 15 Mode switch o setting 2 a RS 232 24V in Figure 9 Direct RS 232 connection to the 1400 1400 User Manual 1400 UM_090105 Page 28 of 104 PSI System Controls and Diagnostics Mode switch on setting 1 USB 24V in Figure 10 Direct USB connection to the 1400 The Diagnostic will see this simple configuration as a loop with just a single device on it Because the direct RS 232 or USB connection does not allow other devices to be seen through that port the 1400 appears as both a loop and a device on that loop Contrast this to the situation where you have a loop controller such as the Pyramid Technical Consultants Inc A100 A200 or A300 devices and the 1400 is connected to the controller via a fiber optic loop In this case the loop controller is identified as the loop and the 1400 as a device on the loop Start the PSI Diagnostic It will search the available ports and present a search a list Figure 11 shows a case where the program found two serial ports a connected USB device the 1400 and a local area network adaptor It will search for loops and devices on all checked options 1400 User Manual 1400 UM_090105 Page 29 of 104 PSI System Controls and Diagnostics amp PSI Loop Diagnostic v4 06 5 olx Actions Window
90. s above the voltages they are trying to regulate or you may cause damage to the 1400 1400 User Manual 1400 UM_090105 Page 59 of 104 PSI System Controls and Diagnostics 16 Connectors 16 1 Front panel connectors 16 1 1 Signal inputs Triaxial female To mate with three lug standard triaxial connector such as Trompeter PL75 7 Core signal at bias voltage 0 400V Inner screen guard a _ at bias voltage 0 400V WS Outer screen NY at chassis ground voltage Two lug connectors are available as an option 16 1 2 Auxiliary HV out SHV male To mate with standard SHV connector such as Radiall R317 005 Core high voltage 0 999V Outer screen shield BN 2 at GND g 16 1 3 Gate input BNC socket female To mate with standard signal BNC Core signal Z 0 5V Outer screen shield x yy at GND 16 1 4 Monitor remote thermistor connection Type OB Lemo four pin female To mate with Lemo FGG 0B 304 or equivalent Pin 1 Pin 4 Thermistor in xy Gnd Pin 2 AA Pin 3 Gnd Analog mon in External view on connector solder side of mating plug 1400 User Manual 1400 UM_090105 Page 60 of 104 PSI System Controls and Diagnostics 16 1 5 Ground lug M4 threaded stud To mate with M4 ring lug 16 2 Rear panel connectors 16 2 1 Power input 2 1 mm threaded jack To mate with Switchcraft S761K or equivalent Center pin 24VDC Outer OV 16 2 2 USB communicatio
91. s and Diagnostics i t Gate A A O S2 V t Figure 25 Example of an external start triggered measurement sequence started by a rising edge Figure 26 shows an External StartStop trigger example The sequence starts on the rising edge as in the previous example However in this case the 1400 is now also sensitive to the falling edge When the gate line falls again the sequence terminates after the acquisition in progress The external signal that starts the measurement sequence can be also be sent over the communications channel as an alternative to making a hardware connection to the gate input connector 1400 User Manual 1400 UM_090105 Page 53 of 104 PSI System Controls and Diagnostics i t D Falling edge signals the end of the Es acquisition sequence T A Open Close Integration in progress is completed x g prog p 2 gt 1 Figure 26 Example ofan external start stop triggered measurement sequence started by a rising edge and ended by a falling edge These acquisition modes would be useful where short pulse of charge for example the macropulse in a pulsed accelerator system needs to be sampled at relatively high rate Figure 27 shows an External Gated example The integration timing in the 1400 is controlled directly by the signal applied to the external gate input in gate trigger mode You can consider that the incoming gate signal is connected direct
92. s ests scksicesscdsngsasasdigevecss seta sedddpteceateosasesdabstseviasaaseasuvessevinstsacssupabsntessaascsdpsbsessestssessagedeciars 60 Signal mputs 2 5 Mines Bae Nes Sala ee Si RS a id 60 Auxiliary HV DU do nl tod 60 Gat einput menoma iaa dada ii hdi ais Ai dida did ba 60 Monitor remote thermistor connection cccooccnooccnonnnonnnononnnonnnonnncnnnnconnnnonnnnnonnnnn cnn nn non nnno nn non nn no nnnnnncnonnnnnnnos 60 A N 61 Rear panel connector Sinai reader iento nase i Eaa a EE a sia 61 POWET PU o do on 61 USB communications Aon hey ci a Aa ei lel tien 61 RS2232 COMUNICA A 61 Fiber optic COMUNICA ii ciel e E AE A E shane EA eset eee ee 61 A Controls and IMdiCatorS i sisicves us sseves ccsnsvescssesechassseveseadecvosessetesouesessshusdeeves ase susaucsssvedesssdessdavecuseedsuecsesuseeessaeet OS Front panel controls A da EEVEE ia acid 63 REA panel control bai 63 Mode Within A a daa aon 63 Address WC li ia a reno naa sE 64 Front panel indicators ia 65 NN 65 Rear panel indicators ii A A O Aa E 65 ELA Ad AA ake 65 USB O Cn ee 65 RS Lila babes ied aia elite eat aiatncs 65 Optical A NON 65 A opt be So eh set tee AM sort ee AANA ce cate a Saat gh A eee ed 65 Rotas ar e id biie 65 MUS a ia 66 Mr A A A AE 66 Internal Switches and jumpers iii dida iii id dali 67 HV option selecto miii iia 67 Externa HV options sineeran R e E N a RE AEE EA R A nee 68 Signal bids HV OPUS resi dt 69 1400 User Manual 1400 UM_090105 Page 4 of
93. shorter than the integration period the 1400 can use sub integration period sampling to track the charge build up on the feedback capacitor between resets as described in the previous section This enables several useful measurement techniques and features in the 1400 When the average current being measured is very low so that a long integration period is needed to get a precise value sub integration sampling allows intermediate current values to be returned rather than having to wait for the integration to end before getting a new reading Time resolved data is available from within the integration period This allows given adequate signal to noise ratio reconstruction of the shape of a pulse that occurred within one integration period A precision calibration voltage is built in to the 1400 It can be switched into each channel where it is converted to a 500 nA calibration current by a high stability resistor Confirmation of correct operation and gain calibration can be performed under remote control Each integrator circuit has a FET switch in series in its input in addition to the reset switch in its feedback loop Operation of this switch in combination with the reset switch allows an integration mode where no charge is missed even during resets This is described in section 13 2 on charge accumulation measurements The on board processor can monitor several additional parameters as well as the integrator outputs The parameters availab
94. tage supplies is fixed and must be specified at time of purchase Units may be returned to the factory to alter the high voltage modules if necessary If your 1400 has both signal bias and external HV supplies these are fully independent The set values can be adjusted at any time independent of what measurements are in progress Any valid setpoint above zero volts enables the relevant supply The HV on LED illuminates when either or both supplies are enabled There is a soft start delay before the HV comes on The readback value of the high voltage is sampled from the HV output It is not as accurate as the set value but does provide a useful diagnostic if the high voltage is being shorted or overloaded Each supply is limited by a software high voltage limit which is password protected and stored in EEPROM in the 1400 The 1400 will reject any attempts to set the voltage higher than the limit This allows sensitive detector systems or experiments which may be damaged by excessive voltage to be protected The maximum current compliance of the high voltage power supplies depends upon the output voltage At low outputs the compliance of the standard high voltage supplies can be represented as the current that the voltage would cause to flow in a resistor of about 300 kohm Thus up to 100 pA is available at 30 V output 200 uA at 60 V output and so on At higher outputs it is limited to 1 mA maximum Lower voltage supplies can be specified at the t
95. tion 12 to learn about these parameters In general the values can be reduced to lower the deadtime proportion at the expense of lower measurement accuracy As an exercise do the following Clear the calibration then click the calibration button and observe that the gain factors change Store this new calibration in the user memory Click the calibration current button to turn on the source and select channel 3 Select le 4 s integration 10 pF feedback capacitor internal triggering and infinite trigger points Now if you return to the data tab and initiate data acquisition you should see the 500 nA calibration current on channel 3 Try displaying the data in histogram mode Setting 100 vertical scale should show the calibration at half of full scale a 1400 7 Address 7 on USB 00000743 o x Comms h A Connected j Pending Error Data Data Current Quadrant Split Initiate Y Measuring Abort Triggering Gated 4 Temp C 1E 06 5 Pres kPa 5E 07 Monitor V Sig Bias V 07 Ext Bias V 5E 07 X Y Gain x 1 000 1E 06 4 J i y y o ETE 0 1 2 3 3 9932 Y Range X Time kB Buffer Couple Mode Run Zero 100 Fast 1177 gt cir Fue pc fHistog MN Set Clear Last Error 9 27 44 PM CALIBRATIONSAVE 203 CommandProtected Figure 14 Internal calibration current routed to channel 2 histogram displ
96. tor A200 USB to fiber optic adaptor A300 fiber optic loop controller Ethernet adaptor A500 intelligent cell controller with Ethernet interface 1400 User Manual 1400_UM_090105 Page 12 of 104 PSI System Controls and Diagnostics 6 Intended Use and Key Features 6 1 Intended Use The 1400 is intended for the measurement of small charges or corresponding currents from pA to uA generated by devices such as ionization chambers in vacuum beam position monitors proportional chambers and photodiodes Four input channels make the 1400 particularly well suited to four quadrant electrode systems used for beam centering The 1400 has design features which make it tolerant of electrically noisy environments but the place of use is otherwise assumed to be clean and sheltered for example a laboratory or light industrial environment The unit may be used stand alone or networked with other devices and integrated into a larger system Users are assumed to be experienced in the general use of precision electronic circuits for sensitive measurements and to be aware of the dangers that can arise in high voltage circuits 6 2 Key Features Highly sensitive charge and current measuring system Four fully parallel gated integrator ADC channels External gate input Multiple data acquisition modes continuous current measurement continuous charge integration no lost charge integration external gated charge integratio
97. tors and conductors in signal cabling free charge is released This is particularly the case for the screen of coaxial cable The resulting potential difference can drive small currents to the signal conductor across the high impedance of the insulator Additionally charge may leak in directly if there are any breaks in the insulator Special low noise cable is available with graphite lubrication bonded to the insulator to reduce charge generation and to conduct any released charge away harmlessly Other mitigations include keeping the signal cables short and motionless 21 4 Battery Effects Ionic contamination such as salt from fingerprints which connects to the sensitive node can give battery effects particularly in the presence of moisture which can drive unwanted currents Any insulating surfaces in contact with the sensitive node must be clean Humidity levels should be such that there is no moisture condensation Wherever possible the sensitive node should be insulated by vacuum or air 21 5 Piezoelectric Effects Ceramic and plastic insulators can release charge when under mechanical stress which may be collected on the sensitive node The effect is generally small less than 10 pA and can be avoided by eliminating stresses in cables and connections 21 6 Integration Period and Synchronization The 1400 provides considerable flexibility in setting the integration time interval and synchronizing the integration to external eve
98. uctor terminal Frame or chassis terminal Equipotentiality Supply ON Supply OFF CAUTION RISK OF ELECTRIC SHOCK CAUTION RISK OF DANGER REFER TO MANUAL PPO Ot 1400 User Manual 1400_UM_090105 Page 8 of 104 PSI System Controls and Diagnostics 3 Models 1400 Four channel gated integrator electrometer with 10pF and 1000pF feedback capacitors P4 2 Add positive 0 to 400V 200V bias for signal inputs N4 2 Add negative 0 to 400V 200V bias for signal inputs XP10 5 2 Add positive O to 1000 V 500 V 200 V auxiliary bias output XN10 5 2 Add negative 0 to 1000V 500 V 200 V auxiliary bias output TP Add thermistor input and on board atmospheric pressure sensor Cx y Change feedback capacitors to x pF and y pF default is C10 1000 2L 2 lug triaxial input connectors in place of 3 lug M Mounting adaptor plate Example 1400 N4 XP10 TP 2L 1400 User Manual 1400 with 400V negative input bias 1000V positive auxiliary bias output thermistor input and pressure sensor two lug triaxial signal connectors in place of standard three lug 1400 UM_090105 Page 9 of 104 PSI System Controls and Diagnostics 4 Scope of Supply 1400 model as specified in your order USB memory stick containing User manual PSI Diagnostic software guide Software installation guide PSI diagnostic software files USB drivers and utilities Optional items as spec
99. unction FPGA pof file General logic loop message passthrough ADC reading and averaging PIC Boot hex file Boot up code upload PIC Application hex file Main application calibration conversion to floating point values range control HV PSU control I O readback host communications SCPI instrument model The FPGA and PIC microcontroller boot code should not require updating They require access to the circuit board and dedicated programming tools to load new code If either of these codes need to be updated your supplier will contact you and make arrangements either to return the unit for upgrade or to have an engineer call The PIC microcontroller application code may be updated periodically to add new operating features New code releases will be provided by your supplier or can be downloaded from the Pyramid Technical Consultants Inc website The hex file can be loaded using the PSI Diagnostic host without any need to access the unit The upload can be performed directly from the PC host via RS 232 USB or fiber optic or routed via an A500 controller On the Device tab click the Select hex file button and navigate to the relevant file The code will then load The process takes about 20 seconds and the 1400 will start running the new code immediately 1400 User Manual 1400_UM_090105 Page 83 of 104 PSI System Controls and Diagnostics amp PSI Loop Diagnostic v4 06 El x 4 1
100. urrents across insulators now flow to the guard where they do not affect the reading 1400 User Manual 1400_UM_090105 Page 86 of 104 PSI System Controls and Diagnostics V Voltage source OL OL UL insulator OO A bs y y e Figure 36 Guarded input AC fields in the environment can induce AC currents in the sensitive node Depending upon the frequencies and the integration time in use these may appear as noise fluctuation in the signal An outer cable screen is used to shield the sensitive node from external fields In combination with the need to guard the sensitive node the result is that the use of triaxial cable is necessary The core and inner guard screen are at bias voltage and the outer screen is at the chassis ground potential of the 1400 OL m 0 ie HO gt Screen Guard Y e Bias PSU Figure 37 Guarded and screened input 21 2 Temperature Offset factors are generally exacerbated by increased temperatures Temperature fluctuation can appear as variation in the reading When very small currents need to be measured the experimental arrangement should be temperature stabilized as far as possible 1400 User Manual 1400_UM_090105 Page 87 of 104 PSI System Controls and Diagnostics 21 3 Triboelectric effects When there is relative movement of insula
101. utton to reset the fields to zero SafeState Enabling SafeState will cause the 1400 to go to its defined safe state 1f there is a communications timeout In particular the HV supply will be turned off Comm Term These controls affect behavior of the 1400 when in ASCII terminal mode Comm Checksum You can ignore them when using the PSI Diagnostic Frequency This parameter sets the averaging period that will be used for calibration You should set it to the dominant electronic noise frequency in your 1400 User Manual 1400 UM_090105 Page 36 of 104 PSI System Controls and Diagnostics environment normally the line frequency SerialNumber This is the manufacturing serial number of your device and should be left unchanged Comm Timeout This field can be used to control how the 1400 behaves if the communication link to its host is lost Entering any non zero integer value sets the number of seconds that the 1400 will continue what it is doing if communications are lost After that it will go to its defined safe state Select hex file This button starts the 1400 firmware update process It opens a file selection dialog When you select a hex file 1t will start uploading to the 1400 immediately Upon completion the 1400 will restart automatically and you will see the new Device Version number displayed Reset This button causes a full warm reset of the 1400 Any acquisition in progress w
102. y RST Reset Command Return the device to the RST default conditions SRE Service Request Enable Command Program the Service Request Enable Register lt 8 bit value gt Not currently supported SRE Service Request Enable Query Query the Service Request Enable Register 1400 returns decimal value Not currently supported STB Read Status Byte Query Query the Status Byte Register 1400 returns decimal value 1400 User Manual 1400 UM_090105 Page 76 of 104 PSI System Controls and Diagnostics TST Self Test Query Perform a checksum test on ROM and return the result 1400 returns lt 1 gt WAI Wait to Continue Command Wait until all previous commands are executed Not currently supported 19 2 3 3 IEEE 488 2 OPTIONAL COMMANDS RCL Recall instrument state from EEPROM SAV Save present instrument state to EEPROM The settings covered by RCL and SAV are SOURce CONFig ACCumulation CAPacitor PERiod CONFig GATe EXTernal POLarity TRIGGER SOURce TRIGger POInts DATa FEEd DATa POINts DATa WRAp Note that the high voltage settings CONFigure HIV Oltage are NOT included 19 2 3 4 1400 COMMANDS ABORt Abort measurement 1400 User Manual 1400 UM_090105 Page 77 of 104 PSI System Controls and Diagnostics CALIBration 1 GA In CLEar Calibrate gain for each channel or reset stored gains to nominal GA In Query gains for each
103. ystem Controls and Diagnostics to external gate No high voltage Shorted to ground in external circuit Monitor HV reading zero or very low relative to setpoint Monitor value recovers if 1400 disconnected from the external circuit Eliminate shorts to ground Cannot set high voltage Trying to set above the maximum allowed value soft limit Sets OK if a lower value is chosen If allowed increase the maximum allowed value Unable to communicate with 1400 Wrong mode switch or address setting Check mode switch setting against table in section 17 and address against expected address in host software Use correct switch settings Switches can be changed while the unit is operating Unable to connect on fiber Connector still fitted to RS232 Remove RS232 and USB loop or USB connectors Communications interruptions Other processes on PC host Use a dedicated PC with interfering with comms ports simple configuration and minimum number of processes running Unable to connect on USB Missing or incorrect USB driver Device connected tone not heard when connecting the USB cable Install correct driver Refer to the 1400 Software Manual Unable to connect on RS232 Another program is using the COM port Try to access the required port with Windows Hyperterminal Choose another port or close down the other program 1400 User Manual 1400_UM

User Manual - Pyramid Technical Consultants

Contents

Download Pdf Manuals

Related Search

Related Contents