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1. 24 829 1 TTRACe DEV24H 8 33 933 8 33 1 pps 930 10 gt 8 29 8 30 m amp x 8 32 Acquire Antenna Cable 8 17 Antenna Installation 8 37 Antenna Location 8 38 Appendix un Alphabetical Overview of Commands 8 30 Antena 2 2 eh eda 8 38 8 37 8 30 8 37 8 15 8 15 8 14 Attenuators 8 7 Auxiliary 8 7 B Bar Graph Display 3 2 Basic Controls 3 2 Basic Programming Information 8 10 C Calibration uam errem Ee 6 2 Calibration History 1 2 Calibration Protocol 4 5 Case Classification 8 4 Cesium Standards 1 2 Check List muni mmn 2 4 Coaxial Adapters 8 7 Coaxial 8 7 Command 8 10 Communication 4 6 Connecting to a 2 8 Controls innan a eee 7 4 D Default Mode
2. 4 10 9 4 Chapter 10 Service Sales and Service Office For service information contact your Fluke service center To locate an authorized Service center visit us on the World Wide Web http www fluke com or call Fluke us ing any of the phone numbers listed below 1 888 993 5853 in U S A and Canada 31 402 687 200 in Europe 1 425 356 5500 from other countries Il
3. Installation Installation GPSView Instrument Instrument Settings Interference Internal Data Storage Introduction e te Introduction to Programming K Keyboard and Indicator Test L LED Indicators Lightning Arresters Index Line Amplifiers reet 8 7 Protection Against Lightning Strikes 8 4 Long term Uncertainty 3 4 R M Rackmount Adapter 2 6 Mean Offset 1 2 Rear Panel zr eae Reve ds 3 3 Measurement Principle 3 5 Rear Panel Outputs 5 3 Mounting Masts 8 8 Recommended Test Equipment 5 2 Multi path Reception 8 3 Remote Error Messages 8 44 N S National Standards 1 3 Safety Instructions 2 2 O SCPI Programming Language 8 10 Specifications dace ae br 7 1 Operating MOES cest udo pedites 1 3 Standard Configuration 8 3 Option 70 10 MHz 5 3 Standard Reference Outputs 7 3 Option 70 Outputs 7 3 Summary of 8 11 Option 71 0 1 to 10 MHz Check 5 3 Supply 2 5 Option 71 Outputs ossis 7 3 5
4. 2 2 Option 72 2 048 MHz Check 5 4 Option 72 Outputs 2 2 ee 7 3 T Option 75 Pulse Output Check 5 4 Test of Ethernet Connection 5 4 Option 75 Output sede Seeks 7 3 Test of PC Connection 5 4 Optional Accessories 7 6 Text Display 4 2 Optional Outputs 2 c bet 1 2 TIE aest taret ER e Ed 3 5 Order of Execution 8 12 Traceable Frequency Standard 1 2 Ordering Information 7 6 Transfer of Archived Data 4 2 Orientation and Cooling 2 5 Transfer of Control Commands 4 2 Overview of Command Subsystems 8 11 Transfer of Stored Data 4 2 P Typographic Conventions 8 11 PC Connection cis ccc ones hte 7 5 U Performance Check 5 1 UNPACKING 2 4 Phase Noise 7 2 Update Database 4 5 Power Consumption 7 6 Using the Controls 3 1 Power Splitters 8 7 V Power On TeSt 5 2 Practical Examples a5 VIEWMENU TB Preface eer i e aec 1 1 W Preparation for Use 2 1 Window Menu 4 8 Preventive Maintenance 6 1 Me rr 4 2 Z Program Sequence 8 12 Zooming
5. total amplification total amplification guard band guard band gt 1 dB lt 33 dB m Case Classification The distance between antenna and receiver exceeds 20 m but not 55 m Use a coaxial cable of type RG 213 or cascade two or three pieces of option 02 by means of adapters Note that normal adapters are not weatherproof and should be placed indoors Normally there is little to gain by using a low loss cable in this case but see example 1 below RG 213 is more inexpensive and flexible The distance between antenna and receiver exceeds 55 m but not 130m Use a low loss coaxial cable of type LMR 400 or equivalent The distance between antenna and receiver exceeds 130 m but not 245 m Use a line amplifier with a nominal gain of 20 dB plus low loss coaxial cable of type LMR 400 or equivalent The ampli 8 4 Appendix 1 Antenna Installation fier must accept a fixed 5 V supply volt age fed through the central conductor of the coaxial cable The maximum input power for linear operation should be at least 6 dBm and the noise figure should be less than 2 dB The distance between antenna and receiver is in the range 245 360 m Use two cascaded line amplifiers 20 dB each plus low loss coaxial cable of type LMR 400 or equivalent Better protection against lightning strikes needed Lightning protection is a wide field and cannot be covered more than superficially in this man ual If the
6. Note The user must manually correct for daylight saving time The value setting is stored in non volatile memory Example SEND gt SYSTem TZONe 1 0 lt nl gt 8 37 Appendix Command Reference Appendix This sets the time zone to GMT 1 and no daylight saving time Query Syntax SYSTem TZONe lt nl gt PTIMe TZONe lt nI gt Response format lt h h m m gt nl Example SEND gt SYSTem TZONe lt nl gt READ lt 1 0 lt nl gt Leap second difference between UTC and GPS time Query Syntax PTIMe LEAPsecond ACCumulated lt nl gt Response format numeric data gt lt nl gt Example SEND gt PTIMe LEAPsecond ACCumulated lt nl gt READ 13 nl PTIM LEAP ACC Leap second pending PTIM LEAP STAT Purpose Tells if there s a leap second pending at the end of month Several weeks before a pending leap second the GPS system broadcasts a special message notifying the user of the event Query syntax PTIMe LEA Psecond STATus lt nl gt Response format 0 1 lt nl gt Example SEND gt PTIMe LEAPsecond STATe lt nl gt READ I nl In this example a leap second is pending 8 38 Appendix 3 Command Reference Appendix Leap minute duration PTIM LEAP DUR Purpose The duration of the minute at next leap time Query syntax PTIMe LEAPsecond DURation nl7 Response format 59 60 61 lt gt Example SEND gt PTIMe LEA Psecond DURation lt n
7. 1 3 Deviations from the Standard Configuration 8 3 Device Error Messages 8 9 Dimensions and Weight 7 5 Disciplining 2000000 1 2 Disclallher eese me Seen et arenes I IV Display Indicators 7 4 E Edit Graphs 222 dee ix 4 10 Edit Menu us ovest epe 4 7 Edit the X axis s cocer 4 10 Edit the 4 10 Editing Marker Lines 4 11 Environmental Conditions 8 5 Environmental Data 7 5 Ethernet Configuration 4 4 Ethernet Connection 7 5 Example 8 10 F aout necu erede IRE EG E dete 7 5 Fan Gontrol c corra Fan Replacement FILE Menu ios dade meni d File Storage Filename Extensions First time Installation Fold down Support Frequency Offset Calculation Test Frequency Stability Front Panel Controls GPS GPS Satellites GPSView Screen Graphical Display Graphs in GPSView Groundirg rre H Help Menu High frequency Interference Hold over Mode Identification Included Accessories Indicators
8. Freq offset 24h Archive data 4 5 The GPSView Screen GPSView Instrument Menu Self test run instrument self test Settings instrument settings con trol panel GPS status display GPS receiver status position display current GPS po sition time display current GPS time satellite info get satellite information from the GPS receiver Connect connect to instrument Disconnect disconnect from instru ment Communication change port and or IP port address used to com municate with the in strument initiate GPS receiver position survey Warning This may cause unstable fre quency output for sev eral hours Restart instrument restart the instrument Warning This may cause unstable fre quency output for sev eral hours Initiate survey 4 Status Position Gonnect Disconnect Time Satellite Communication Port ro Set Position Initiate Survey 4 6 The GPSView Screen GPSView Communication Port x m Serial Port Use Ethernet GT Ethernet CDM IP 0 0 0 0 Gog OK Cancel m Communication Port Dialog Box This dialog box will enable you to select the communication port used to communicate with the instrument or the IP address used if the op tional Ethernet interface is installed Note The IP address shall be the same as the one configured in the instrument see Ethernet Configuration on page 4 4 m Instrument
9. VALid lt nl gt READ 1 lt nl gt 1 pps signal status GPS REF STAT Purpose Returns status of the GPS 1 pps system Query syntax GPS REFerence STATe lt nl gt Response format ID ID ID ID ID ID ID ID LTE LTE LTE LTE LTE LTE LTE LTE limit sigma pps sol stat alg p ulse sync lt nl gt ID Satellite ID 8 LTE Local Time Estimate 8 in ns 0 999 999 999 limit Time RAIM alarm limit in 100 of ns 3 65535 sigma Time solution one sigma accuracy estimate in ns 0 65535 1 1 PPS control mode 8 33 Appendix 3 Command Reference Appendix 0 always off 1 always on 2 on when at least one satellite 3 on when RAIM algorithm OK sol Time RAIM solution status 0 OK 1 alarm 2 unknown due to threshold too low RAIM algorithm off or insufficient satellites stat Time RAIM status 0 detection and isolation possible 1 detection only possible 2 neither possible alg Time RAIM algorithm on off 1 on 0 off pulse Pulse status 1 on 0 off sync PPS pulse sync 1 GPS 0 UTC Example SEND gt GPS REFerence STATe lt nl gt READ lt 29 8 9 5 4 24 30 7 371501 457686 457526 457553 835812 457646 457537 923080 10 49 1 0 0 1 1 0 lt nl gt GPS receiver firmware GPS VERS Purpose Check GPS receiver firmware status version amp revision Query syntax GPS VERSion Response format lt integer gt lt integer gt lt nI gt Example SEND
10. external frequency comparator and an external frequency standard for comparison Now the timer counter frequency comparator and a very stable secondary standard is together with the GPS receiver built into one and the same box see fig 2 The received GPS signal is continuously measured against the local oscilla tor and the frequency deviation is stored in a non volatile storage and can at any time be transferred to a PC for print out of a traceability frequency standards The 910 910R are very suitable as frequency standards in the telecom munication and electronics indus try They fit in the calibration labo ratory as frequency reference in test systems and as a local reference in Frontpand dis of frequency offs et 1 pps output Rubidium ar OCXO oscillator 10 and5 MHzoutputs other frequencies programmable pu se To PC RS232 the design department Figure 1 2 Unique Traceable Frequency Standard Off air frequency standards have existed for several years with the same internal architecture see figure 1 The unit is a black box for the user with an antenna input and a frequency out put The control process disciplining of the lo cal oscillator is totally hidden for the user The only way to monitor the performance is to use an The 910 910R have built in comparison between the GPS receiver and the internal oscillator record The unbroken calibration his
11. gt GPS VERS lt nl gt READ 3 2 lt nl gt m Synchronization of GPS received signal with local oscillator Hold over duration SYNC HOLD DUR Purpose Retrieve latest hold over duration and status Query syntax SYNChronization HOLDover DURation lt nl gt 8 34 Appendix 3 Command Reference Appendix Response format lt duration gt 0 1 lt nl gt Note lt duration gt numeric data of current or most recent hold over period is expressed in seconds with 30s resolution The status tells if the instrument is currently in hold over 1 or not 0 The response is 0 0 at start up Example SEND gt SYNC HOLD DUR lt nl gt READ lt 150 1 lt nl gt The instrument has been in hold over for 150s and is still in hold over Selecting manual Hold over mode SYNC HOLD INIT CAL AUTO OFF Purpose Set manual hold over mode Command syntax SYNChronization HOLDover INITiate or CALibrate AUTO OFF Example SEND gt SYNC HOLD INIT Selecting GPS disciplined mode SYNC HOLD REC INIT CAL AUTO ON Purpose Set GPS disciplined mode Command syntax SYNChronization HOLDover RECovery INITiate or CALibrate AUTO ON Example SEND gt CAL AUTO ON Operational mode SYNC STAT Purpose Retrieve current status of frequency standard mode Query syntax SYNChronization STATe lt nl gt Response format HOLD LOCK WAIT POW lt nl gt 8 35 Appendix 3 Command Reference Appendix Note HOL
12. Automatic satellite survey mode Command syntax GPS POSition SURVey STATe ONCE lt nI gt Parameters Parameter ONCE starts automatic surveying has accuired 10000 position fixes Query syntax GPS POSition SURVey STATe lt nl gt Response format 0 1 lt nl gt This surveying mode ends when the GPS receiver Note 1 Surveying mode is TRUE 0 Surveying mode is FALSE Example SEND gt GPS POS SURV STAT lt nl gt READ 0 lt nl gt The GPS receiver is not in the surveying mode in this example Satellite tracking elevation mask GPS SAT ITRAC EMAN Purpose Enables a minimum elevation mask angle for satellites to track Command syntax GPS SATellite TRACking EMANgle numeric data gt lt nl gt Note numeric data is the minimum mask elevation angle of the satellites to track Range is 0 89 degrees 0 degrees means no masking 89 degrees means only satellites passing right above the antenna 90 degrees are tracked The value is stored in the non volatile memory Query syntax GPS SATellite TRACking EMANgle lt nl gt Response format numeric data gt lt nI gt Example SEND gt GPS SAT TRAC EMAN 30 lt gt SEND gt GPS SAT TRAC EMAN lt nl gt READ 30 lt 1 gt 8 29 Appendix 3 Command Reference Appendix Satellite tracking data Purpose Retrieves list of tracked satellites Query syntax GPS SATellite TRACking lt nl gt Response format lt list gt
13. Example 1 Requirements Cable length 52 m 5 m indoors Lightning arrester yes Climatic conditions normal Solution The cable length indoors i e after the lightning arrester must be at least 8 m otherwise the pro tective function may not be guaranteed So you have to make the cable 3 m longer indoors The effective cable length will be 55 m instead This is the upper limit for the standard RG 213 ca ble under normal climatic conditions Calculation of total gain at the receiver input using a RG 213 cable with an attenuation of 0 40 dB m 40 dB per 100 m under normal environmental conditions Antenna gain 36 dB Cable loss 22 dB 55 0 40 Guard band 3 dB Total gain 11 dB 36 22 3 This gain figure is exactly at the lower permis sible level at the receiver input Example 2 Requirements Cable length 55 m 50 m indoors Lightning arrester Climatic conditions snow and ice Solution The cable length 55 m is the upper limit for the standard RG 213 cable under normal environ mental conditions But snow and ice on the surface of the antenna can attenuate the signal by 6 dB Let us calculate total gain at the receiver input for a RG 213 cable taking the snow and ice factor into consideration Antenna gain 36 dB Harsh weather 6 dB Cable loss 22 dB 55 0 40 Guard band 3 dB Total gain 5 dB 36 6 22 3 The latter figure should be in the range 11 33 dB so the
14. File storage 24h offset and adjustment values main da tabase file any graph data Installation Run the installation program SETUP exe from installation disk 1 Follow the instructions on screen GPSView The GPSView Screen FILE menu Common FILE actions like Open Save Print Acquire Reads data from connected in strument Help Help topics and about GPSView Menus Tool bar Status bar View Shows or hides the Toolbar and the Status bar Instrument Connect disconnect the instrument Read and change settings 4 3 The GPSView Screen GPSView Ethernet Configuration FILE Menu Note These instructions are only valid 1f Op tion 76 is installed Open open an existing data set lose lose the acti h You have to configure the network parameters close e P Save save the data of the active before first use This is performed under nstru graph ment Communication Port on the menu bar Save as save the data of the active pee graph with a new Select database select the database to use for the reference history Close database close the currently se Note The network parameters are entered us ing the standard RS232 interface port Check the box Use Ethernet press the button lected database Configure Instrument and follo
15. Note 2 Internally stored TIE values sampled every 30s are kept for 2 5 days These fre quently sampled values are used in the uncer tainty calculation for as long as there is data available m Print Calibration Protocol A calibration protocol is based on the data in the instrument s database file normally called Ref erence History This database file contains the instrument ID user ID the 24h mean frequency offset per calendar day and the calculated un certainty for each frequency offset value The instrument ID in the protocol is automati cally fetched from the connected instrument The user ID is fetched from the Registry infor mation Windows Before the first calibration protocol print out the user information must be entered via Set user information The user can enter arbitrary information on max 6 lines e g name company name address etc Once en tered this information will automatically be fetched for future calibration protocols Acquire Menu Reads data from connected instrument You can choose between Phase deviation get a new phase devi ation graph based on 30 s samples TIE 1h get a new phase devi ation graph based on h samples Frequency offset 1 geta new 1 h mean hour frequency offset graph Frequency offset 24 geta new 24 h mean hours frequency offset graph Archived data get a new graph of frequency reference history Phase deviation TIE TIE 1h Freq offset 1h
16. Performance Check General Information Preparations bended ace Front Panel Controls Rear Panel Outputs Test of PC Connection Test of Ethernet Connection 6 Preventive Maintenance Calibration as 2 s Fan Replacement 7 Specifications Frequency Stability Ordering Information 8 Appendix Appendix 1 Antenna Installation Appendix 2 Device Error Messages Appendix 3 Command Reference Appendix 4 Remote Error Messages 9 Index 10 Service Sales and Service Office 10 11 Warranty Statement This Fluke guarantee is in addition to all rights which the buyer may have against his supplier under the sales agreement between the buyer and the supplier and according to local legislation Fluke guarantees this product to be free from defects in material and workmanship under normal use and service for a period of one 1 year from the date of shipment This guarantee does not cover possible required re calibration and or standard maintenance actions This guarantee extends only to the original end purchaser and does not apply to fuses batteries power adapters or to any prod uct or part thereof that has been misused altered or has been subjected to abnormal conditions of operation and handling Fluke supplied software is guaranteed to be properly recorded on non defectiv
17. Syntax ESE lt nl gt Returned Format lt dec data gt the sum between 0 and 255 of all bits that are true lt nl gt Example SEND gt ESE lt nl gt READ lt 4 nl In this example only the query error enable bit is set 8 25 Appendix 3 Command Reference Appendix Option query OPT Purpose Lists the options of the instrument Command Syntax OPT lt nl gt Response format lt Inputs gt lt Timebase gt lt Outputs gt lt nl gt Inputs is currently always 0 Timebase is Oven 6 or Rubidium Outputs is 0 or Pulse Output option 75 Example SEND gt OPT lt nl gt READ 0 Rubidium 0 lt nl gt Service request enable query SRE SRE Purpose The SRE command sets the Service Request Enable Register bits A bit that is set true in the SRE register enables the corresponding bit in the Status Byte Register to generate a Service Re quest Command Syntax SRE lt dec data gt lt nl gt lt dec data gt the sum between 0 and 255 of all bits that are true lt Integer gt Status 128 Bit 7 Measurement started 64 Bit 6 Request Service 32 Bit 5 Event status bit 16 Bit 4 Message available 8 Bit 3 Not used 4 Bit 2 Error available 2 Bit 1 Not used 1 Bit 0 Not used Example SEND gt SRE 32 lt 1 gt In this example the Event Status bit bit 5 is set and a Event Status bit that is set true in the Status Byte Register will generate a Serv
18. a rule of thumb assume a delay of 5 ns m This value is stored in non volatile memory Elevation Mask Angle The GPS receiver will not attempt to track any satellite that is predicted to be below the eleva tion mask angle If the GPS antenna has a free horizon view this value should normally be left at zero but if the horizon is hidden you may wish to increase the value in order to lessen the risk ofthe GPS receiver trying to track erroneous signals This value is stored in non volatile memory Time Zone Set these values according to your time zone if you wish the instrument to report local time rather than UTC You will need to change these values to compensate for Daylight Savings Time ifthat is in effect These values are stored in non volatile memory Pulse Output Option 75 only Set the pulse period and pulse width to what ever values you wish to have on your program mable pulse output The period should be be tween 200 ns and about 27 s and the width be tween 100 ns and about 27 s Both can be set with a resolution of 100 ns These values are stored in non volatile memory Primary Display This setting lets you decide whether the 24 hour mean frequency offset or the current time should have higher priority to the display At any time the display shows the highest pri ority message that is available and considered valid The priority order is Alarms Other system messages DEV24 and TIME in the order you s
19. additional 6 dB loss due to extreme weather conditions requires the use of a low loss cable e g LMR400 having an attenu ation of 0 17 dB m 17 dB per 100m This gives the following total gain 8 5 Appendix 1 Antenna Installation Appendix Antenna gain 36 dB Example 4 Harsh weather 6dB Requirements Cable loss 9 dB 55 0 17 Guard band 3 dB le length 325 m 120 Total gain 18 dB 36 6 9 3 Cabl lenig T Lightning arrester yes This gain value is well within the acceptable range Example 3 Requirements Cable length 130 m 120 m indoors Lightning arrester Climatic conditions normal Solution As this cable length suggests the use of a line amplifier let us check that the total gain at the receiver input does not exceed the maximum value allowed 33 dB Antenna gain 36 dB Amplifier gain 20 dB Cable loss 22 dB 130 0 17 Guard band 3 dB Total gain 37 dB 36420 2243 This calculation means that if the weather is fine and the antenna gain is at its positive toler ance level then the signal should be attenuated by at least 4 dB to avoid overloading the re ceiver input external 6 dB attenuator di rectly on the input connector takes care of the problem As the cable length outside the building is not more than 10 m limit 15 m a lightning arrester is not compulsory 8 6 Appendix 1 Antenna Installation Climatic conditions snow and ice Solution Th
20. building is situated in a risk area a general survey of the overall house protection might be needed Especially lightning rods near the GPS antenna mounting mast should be in spected Make sure that the antenna is far from being the highest point and as a precaution ground the mounting mast as if it were part of the ordinary lightning rod system There are several conditions that may call for a separate lightning arrester to support the built in antenna protection The cable length outside the building ex ceeds 15 m An elevated antenna position with no effi cient lightning rods nearby Areas where the frequency of thunder storms is significantly higher than normal Extra safety wanted due to sensitive and or expensive equipment being connected to the GPS timebase system A lightning arrestor should be mounted inside the building close to the cable entry point Appendix Harsh environmental conditions Snow and ice on the surface of the antenna can significantly reduce the effective sensitivity by as much as 6 dB You could for instance utilize an electrically heated radome to house the an tenna unit to avoid the attenuation effects of this environmental influence Other weather conditions having negative in fluence on the system sensitivity are heavy rain and fog The attenuation effects are normally covered by the 3 dB guard band used in the cal culations m Four Practical Examples
21. data gt will follow 2 means that the two following digits will specify the length of the data block 40 is the number of characters in this example SEND gt PUD lt nl gt READ lt 240ACME Inc Bobby Brown inventory No 1234 lt nI gt Note SYST UNPR means unprotect and enables writing of protected user data This command is only used here and not further explained m Internal operations commands Operation Complete Query OPC Purpose This command is used to synchronize the execution of the programming sequence with the actions in the controller This is used by adding the OPC at the end of the command sequence The operation complete query places an ASCII character 1 in the devices output queue when all pending selected device operations have been finished This command causes the device to generate the operation complete message in the Standard Event Status Register when all pending selected device operations have been finished Response syntax 1 nl Example SEND gt SYST TZONe 1 0 OPC lt nl gt READ 1 nl SEND gt SYST TIMe lt nl gt READ lt 12 17 23 nl 8 22 Appendix 3 Command Reference Appendix Reset RST Purpose Resets the frequency standard to the same state as after a power down power up se quence Command Syntax RST lt nl gt Example SEND gt RST nl Self test TST Purpose The self test query causes an internal self test and generates a response ind
22. i e empty string lt X unit gt is the time scale unit s for X i e real time timestamps The binary data contains timestamps X frequency offset Y 1 and timebase oscillator adjustment Y2 values Each value occupies 8 bytes of binary data in the 64 bit IEEE floating point numbers stored in s c little endian format Each binary block contains one X one Y1 and one Y2 value that is totally 3 8 24 bytes of data The complete binary block has the format 224 lt gt lt 1 gt lt Y 2 gt The blocks are transferred one by one from the 910 910R until the last data triplet in the non volatile storage array is reached Then the termination block 10 is sent Note unlike the other TRAC Commands there is no sample parameter in the header and there is no a priori block size that could be read from the first characters of the binary block Instead multi ple binary blocks containing one data triplet each are transferred and the receiving controller must check for the termination block 10 X is the absolute timestamp value in seconds since 00 00 00 on January 1 1980 ignoring leap seconds Y 1 gt is the relative frequency deviation from nominal measured as an average over 24h lt Y2 gt is the oscillator adjustment value expressed as relative frequency offset from midrange set ting 8 16 Appendix 3 Command Reference Appendix Select output signal SOUR PULSe only option 75 Purpose The
23. in expression 270 Macro error out of definition space 270 Macro error out of name space 270 Macro error 271 Macro syntax error 272 Macro execution error 273 Illegal macro label 274 Macro parameter error 275 Macro definition too long 276 Macro recursion error 277 Macro redefinition not allowed 278 Macro header not found 280 Program error Appendix 4 Remote Error Messages Appendix 281 Cannot create program 350 Queue overflow 282 Illegal program name 400 Query error 283 Illegal variable name 410 Query INTERRUPTED 284 Program currently running 410 Query INTERRUPTED in query state 285 Program syntax error 410 Query INTERRUPTED in send state 286 Program runtime error 410 Query INTERRUPTED in response state 300 Device specific error 420 Query UNTERMINATED 310 System error 420 Query UNTERMINATED in send state 311 Memory error 420 Query UNTERMINATED in idle state 312 PUD memory lost 420 Query UNTERMINATED in read state 313 Calibration memory lost 430 Query DEADLOCKED 315 Configuration memory lost 440 Query UNTERMINATED after indefinite 330 Self test failed response 8 46 Appendix 4 Remote Error Messages Appendix DEVICE SPECIFIC ERRORS 1100 1101 1102 1110 1120 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1150 1160 1170 1180 1181 1190 1200 1201 1202 1203 1204 1210 Device operation gave floating point 1211 Wrong macro table checks
24. in the GPS disciplined mode with just two tracked satellites When Locked to GPS is lit the frequency standard op erates in disciplined mode and there is sufficient GPS satellite contact When not lit the frequency 3 2 Basic Controls standard operates in Hold Over mode whether manual or caused by insufficient GPS signal re ception a wy Using the Controls Rear Panel Option 75 optional pulse output De fault setting 1Hz Frequency is Connector for optional 1 pps output pro changed via Ethernet interface Op vides 1 pulse per GPSView tion 76 second synchro nized to UTC Antenna cable Power input input 90 265V N contact 47 63Hz f p NS LJ UV 0 athe s 228 050 9 25 000 000 e000 9 0 0 0 0 0 0 4 EI EI JDO 0009 0000 A RS22 Co Co asses iit OESTE CX 7 VY Option 70 extra outputs 5x10 MHz sine wave RS232 port for 5 MHz 10 MHz connection to PC standard standard oF output outputs Option 71 extra outputs 1x10 MHz 1x5 MHz 1x1 MHz 1x0 1 MHz sine wave 1x0 1MHz Switch for inter square wave face selection Option 76 or Option 72 extra outputs 5x2 048 MHz sq wave 3 3 Rear Panel a Using the Controls Func
25. lt nl gt Note lt list gt Returns zero if there are no satellites tracked Example SEND gt GPS SAT TRAC lt nl gt READ 7 12 15 lt nl gt In this case the satellites with IDs 7 12 15 were tracked GPS SAT TRAC Satellite tracking data Purpose Retrieves the number of tracked satellites Query syntax GPS SATellite TRACking COUNt lt nI gt Response format numeric data gt lt nl gt Example SEND gt GPS SAT TRAC COUN lt nl gt READ lt 6 lt nl gt GPS SAT TRAC COUN Satellite status Purpose Returns system status of the GPS receiver Query syntax GPS STATe lt nl gt SYSTem STATe lt nl gt Response format GPS STAT ISYST STAT date time latitude longitude altitude velocity heading DOP DOP type vis trac ChanData ChanData ChanData ChanData ChanData ChanData ChanData ChanData rs lt nl gt Date yyyy m m d d Time h h m m s s Latitude N S dd d m m s s ff f 8 30 Appendix 3 Command Reference Appendix Longitude E W dd d m m s s ff f Altitude m f f Velocity in cm s 0 51400 0 514 00 m s Heading in 0 1 degrees 0 3599 0 0 359 9 degrees DOP in 0 1 resolution 0 999 0 0 99 9 DOP DOP type Vis Number of visible satellites Trac Number of tracked satellites 8 ChanData Satellite ID gt lt Track mode gt lt Signal strength gt lt Channel status RS Reciever status Example SEND gt GPS STATe
26. modes modes 1 pps approx 0 V 5 V in open Jitter 0 01 UI output approx 0 V 2 0 Vin 50 Q load Option 75 Output Duty cycle Approx 20 The frequency is adjustable via the included GPS locked PC program Jitter 60 ns rms relative to UTC or GPS locked GPS position hold SA on Pulse output approx OV 5Vin open output Option 70 Outputs approx 0 V 2 0 V i in 50 Q load See specification for 10 MHz above Selectable period Nx100 ns 24228 200 ns to 27s Option 71 Outputs 0 04 Hz to 5 MHz Selectable pulse width Nx100ns Sine wave 10 5 1 and 0 1 MHz Range 1537 1 outputs gt 1Vrms in 50Q 100 ns to 27s Factory default setting Pulse output 0 1 MHz gt 3Vp p in 50 2 Frequency 1 Hz Period 1s OVSLOX lt 0 8V 3V lt HIS5V Duty cycle 50 Pulse width 0 5 s Freq stability See frequency stability Jitter lt 500 ps rms specs for 910 resp 910R for Freq stability See freq stability GPS locked resp specs for 910 resp hold over modes 910R e 7 3 Frequency Stability e Specifications Internal Data Storage 24h freq offset archive data 72 years of data non volatile memory Adjustment data 24h gt 2 years of data Freq offset 1h Freq offset 24h 30s phase deviation 1 h phase deviation Controls Manual hold over non volatile memory gt 7 days of data vola tile memory gt 7 days of data vola tile memory 22 days of data vola t
27. should be near the specification 2 10712 910 or 1 ur 910R If not check if it has had continuous satellite contact and that the ambient tempera ture has been stable within 3 degrees Redo the test Rear Panel Outputs 10 MHz Connect a DSO with 50 Q inputs to all 10 MHz Out BNC connectors one at a time Ver ify that the output signal is sinusoidal and that the voltage is at least 600 mVrms Connect a PM 6681R counter and verify that the fre quency is 10 MHz 0 01 Hz 5 MHz Connect a DSO with 50 Q inputs to the 5 MHz Out BNC connector Verify that the output signal is sinusoidal and that the voltage is at least 600 mVrms Connect a PM 6681R counter and verify that the frequency is 5 MHz 0 005 Hz 1 pps Connect a DSO with 50 Q inputs to 1 pps Out BNC connector Verify that the voltage is a square wave and that the low level is lt 0 9V and the high level gt 1 8V Connect a PM 6681R counter and verify that the frequency is 1Hz 1 uHz Option 70 10 MHz Connect a DSO with 50 Q inputs to all 10 MHz Out BNC connectors one at a time Ver ify that the output signal is sinusoidal and that the voltage is at least 600 mVrms Connect a PM 6681R counter and verify that the fre quency is 10 MHz 0 01 Hz Option 71 0 1 to 10 MHz Connect a DSO with 50 Q inputs to all BNC connectors one at a time Verify that the four sine wave output signals are sinusoidal and that the volt
28. the binary data block size is 2 Samples 2 bytes stored in the order X2 Y2 etc Note The order between X Y pairs X before Y in the response to the TRAC DEV1H or TRAC DEV24H query is the opposite compared to the response to the TRAC TIE queries Y before X 8 15 Appendix 3 Command Reference Appendix The value expressed as a relative deviation to nominal frequency of DEV1H or DEV24H corre sponding to the binary value Y is calculated as Yj Y resolution Y zero Note It is possible for the deviation to overflow the range used In this case the value is truncated to the maximum or minimum depending on the sign of the value The absolute value in seconds since 00 00 00 on January 1 1980 ofthe timestamp corresponding to the binary value Xj is calculated as Xj X resolution X zero Fetch data array 24h freq offset non volatile archive TRACe ARC24H Query syntax TRACE ARC24H CH1 lt nl gt Response Syntax lt Channel gt lt Y 1 unit gt lt Y2 unit gt lt X unit gt 224 lt binary data gt 224 lt binary data gt 10 lt nl gt Channel is a string and is either Channel 1 or No trace acquired in the latter case the rest of the response message does not contain valid data but is present ee lt Y1 unit gt is the relative frequency offset unit dimensionless i e empty string ee lt Y2 unit gt is the timebase adjustment data unit dimensionless
29. there is GPS contact Dis ciplined mode is the default mode Hold over mode is automatically entered when GPS disciplining fails for some reason e g loss of GPS contact Hold Over mode can also be forced via the manual Hold Over key or via program commands over the RS 232 port When GPS contact is lost the 910 910R can not be continuously calibrated intercompared with GPS in real time and re verts temporarily to Hold Over mode specifi cations Pros and Cons Disciplined mode gives the user problem free operation the frequency standard has no long Front panel display of frequency offset other frequencies To PC RS232 term drift because it is adjusted when 1 pps needed It is the preferred mode for sta 10 nd5MHzouputs operation Hold over mode is ideal for portable poganmabe puse Operation after change of location Un like the frequency standards that always use disciplined mode a 910 910R is ready to operate within 10 minutes after Figure 3 1 The 910 910R have built in compart power on at the new location Hold over son between the GPS receiver and mode is also preferred when the internal oscillator 3 4 Functional Description short medium term stability is critical Using the Controls e g when used as frequency source for clock wander measurements in SDH SONET tele phone systems The nature of disciplining would cause some a
30. to which it owes much of its struc ture and syntax SCPI can however be used with any of the standard interfaces such as RS 232 This programming reference assumes that the user has good knowledge of SCPI syn tax Such knowledge can be gained by studying commercially available books about SCPI pro gramming Useful information can be found in the Fluke PM6680 81 85 Timer Counter Ana lyzers Programming Manual Order No 4822 872 20081 m Short Summary of Syntax A typical command string may look like this GPS SATellite TRACking COUNt lt nl gt colon A leading colon shows that the following com mand starts from the root level of the command tree A colon ina string separates different parts of a compound header like GPS SATel lite TRACking space Separates header from data quote Single or double quote indicates string data semicolon Separates several program messages in a string question Indicates that a response is requested Parenthesis Indicates Expression data nl new line or lt gt carriage return Ends a message m Typographic Conventions in This Text UPPERCASE Like in PERiod PER is the short form and pe riod is the long form The instrument will act exactly in the same way whichever form you use Sh An expression between these brackets is a code such as nl new line that can not be ex pressed in a printable character or it is a param eter that i
31. will be amplified or attenuated At worst it can vanish Since the GPS satellites are not stationary the conditions can be compared to the fading prob lem on the shortwave bands The directive sen sitivity of the antenna resembles a hemisphere with its base plane going horizontally through the antenna provided it is mounted vertically on top of a mast Therefore you must avoid lo cations near reflective surfaces beside or above the antenna m High frequency Interference Strong signal sources in the vicinity like cellu lar radio transmitters can cause interference or saturation in the antenna amplifier Even though the systems do not operate at the same frequency the problem has still been observed from time to time and must not be neglected Standard Configuration The majority of installations can do with the standard configuration consisting of one GPS antenna one 20 m antenna cable and the GPS controlled frequency reference itself 910 or 910R In many cases the distance between the antenna and the receiver could be less than 20 m Normally excessive cable length is easy to tolerate Do not shorten the cable unless ab solutely necessary because the high antenna gain of 36 dB requires the signal to be attenu ated by at least 6 dB before entering the re ceiver Deviations from the Standard Configuration m General Principles The system configurations that cannot directly use the standard options provided by
32. D Manual Hold over mode LOCK GPS disciplined mode WAIT Waiting to Lock Hold Over due to insufficient GPS satellite contact POW Power up state Example SEND gt SYNC STAT lt nl gt READ lt LOCK nl Frequency output signal quality SSYNC FFOM Purpose Retrieve Frequency Figure of Merit for Frequency Reference Output Query syntax SYNChronization FFOMerit nl Response format 0 3 lt nl gt 0 is highest value and indicates a sufficiently long monitoring and lock of the local frequency os cillator 1 indicates lock to GPS at all of the local frequency oscillator 2 indicates hold over 3 indicates poor output signal during start up Example SEND gt SYNC FFOM lt nl gt READ lt 3 nl 8 36 Appendix 3 Command Reference Appendix m Time and date command Get time SYST TIME PTIM TIME Query Syntax SYST TIME lt nl gt PTIMe TIME lt nl gt Response format lt hh mm ss gt lt nl gt Note The seconds field may be 60 if there is a leap second Example SEND gt SYST TIME lt nl gt READ lt 13 04 27 lt nl gt Get date SYST DATE PTIM DATE Query Syntax SYSTem DATE lt nl gt PTIMe DATE lt nl gt Response format lt yyyy mm dd gt lt nl gt Example SEND gt SYST DATE lt nl gt READ lt 1999 08 12 lt nl gt Set timezone SYST TZON PTIM TZON Command Syntax SYSTem TZONe lt hh mm gt lt nl gt PTIMe ZONe lt hh mm gt lt nl gt
33. Err Ra RAM error detected at power on Err Ro ROM error detected at power on Err ASIC Measurement logic error detected at power on Error Other error Rb Unloc d Rubidium reference unlocked Locked to GPS OFF Hold Over mode GPS contact Satellite Strength Bars Bars Description 0 No antenna 1 Antenna connected but no 11 21 satellite Absolute minimum required to maintain a lock to GPS Absolute minimum required for first lock Good reception Very good reception 3 7 Satellite Strength Bars Using the Controls This page is intentionally left blank 3 8 Satellite Strength Bars Chapter 4 GPSView GPSView Introduction GPSView SW GPSView is a Windows 95 NT program that communicates with the GPS controlled fre quency standard Its main purpose is to provide a traceable calibration document based on the 24h frequency offset values internally stored in the non volatile memory of the 910 910R It is only neccessary to connect a PC to the 910 910R once every second year to obtain an unbroken traceability chain since first use If a PC is permanently connected short term phase variation can also be continuously monitored From GPS View the user can control the operat ing mode disciplined or Hold over and lock the front panel to prevent unintended change via the manual Hold over key GPS View can perform t
34. GPS Controlled Frequency Standards 910 amp 910R Operators Manual 1580336 Fourth Edition May 2002 This manual in whole or in part may not be copied without permission All product names are trademarks of their respective companies 2000 Pendulum Instruments AB All rights reserved Printed in Sweden Il Table of Contents Warranty Statement IV Declaration of Conformity V 1 Preface Introduction ius on tette 1 2 2 Preparation for Use Safety Instructions 2 2 Introduction 2 2 Safety Precautions 2 2 Grodnding 2 2 e ER IER 2 2 UNPACKING seecae xs zr pm 2 4 Unpacking Instructions 2 4 Installation x22 node cs 2 5 Supply Voltage 2 5 Orientation and Cooling 2 5 Fold down Support 2 6 Rackmount Adapter 2 6 Antenna Installation 2 8 Connecting to a 2 8 Optional Ethernet Connection Option 76 2 8 3 Using the Controls Basic Controls 2 nz 3 2 Rear Panel ivo x RES 3 3 Functional Description 3 4 Indicators oe rer uS 3 6 Satellite Strength Bars 3 7 4 GPSView Introduction sss ck ERR RR 4 2 Installation 4 2 The GPSView 4 3 Graphs in GPSView 4 9 5
35. Pendulum can be listed in different ways One simple method of classification used here is to isolate a number of cases and treat them separately If several steps have to be taken to arrive at a solu tion that satisfies all requirements then it should be possible to derive the individual com ponents from the list by means of combination The method is illustrated by some practical ex amples later in this chapter The most important design parameter is the ca ble loss at the receiving frequency 1 575 GHz There are a number of cable types to choose from but for the sake of simplicity one normal and one low loss type have been selected Cable type Attenuation per 100m Standard RG 213 Approx 40 dB Low loss LMR400 Approx 17 dB The common laboratory cable RG 58 has been excluded as its losses only allow relatively short distances between antenna and receiver It is more flexible however and might be utilized with care if you are fully aware of its character istics 8 3 Appendix 1 Antenna Installation Appendix Remaining parameters to consider are Antenna gain 36 dB option 01 Guard band 3 dB Total external gain at the receiver input 114 33 dB When designing your own antenna installation you must check that the gain at the receiver in put is within limits according to the above table That is you must check that antenna gain antenna gain total attenuation total attenuation
36. Reset during bus input 1308 Calibration error noise at comparator Reset during bus output 1309 Calibration error signal above range Bad message exchange controlstate 1310 Calibration error signal below range Unexpected reason for interrupt Mnemonic table error 8 47 Appendix 4 Remote Error Messages Appendix This page is intentionally left blank 8 48 Appendix 4 Remote Error Messages Chapter 9 Index Index CAL AUTO OFF CAL AUTO ON GPSIREF ADEL cum nee GPS REF STAT data eed GPS REF VAL os 9 2 Index PTIM LEAP DUR 0 PTIM LEAP STAT 825 PTIMTIME 825 7 825 1 824 STAT OPER COND STATOPER Z es ovina re el 8 26 SYNC HOLD DUR SYNC HOLDIINIT 0000 923 SYNC HOLD REG INIT 826 5 5 926 SYSTALAR ENAB NOAN 923 929 827 8 35 5 835 840 840 20 8 813 5
37. Settings Dialog Box This dialog box shows you the current values of the instrument settings and lets you change them Note that frequent changes of values stored in non volatile memory will decrease the memory available for the archive data in the in strument s non volatile memory GPSView Instrument Settings x Yee Manual Holdoves 0 Antenna Cable Delay T Keyboard Lock Cancel V Antenna alarm enable p Elevation Mask Angle r Time Zone Pulse Output Primary Display NN Hours fo Period s DEV24 C TIME 0 Minutes 05 Width s EAT Manual Holdover Check this if you want to force the frequency reference into holdover free running mode GPSView and uncheck it if you want the reference to be disciplined by GPS Keyboard Lock Check this to lock the front panel key and uncheck it to allow front panel access No Antenna alarm enable If you have a GPS antenna that uses less power than the GPS receiver expects a No Antenna alarm is normally shown but the GPS receiver should work anyway If you have such an an tenna you probably want to disable the alarm by unchecking this box otherwise you are ad vised to leave it enabled This enable status is stored in non volatile memory Antenna Cable Delay If you wish to have the best possible synchroni zation of the 1 pps output to UTC you should specify the delay of the GPS antenna cable here Check the specification for the cable or as
38. Sie Hold over offset selected by user DE ON valid The There is or has re tly been suffi time of day dis j play is selected in cient GPS contact stead of freq off Calibration process set OR pea dion is valid lt 24h from Manual Time of Manual Hold over power on or poor Hold over day selected by user GPS contact for a ON GPS time data is long time vad 10 Locked to 910 Disciplined mode time of day display GPSON or There 18 is selected instead 9108 GPS contact Op of freq offset OR eration 24h from operation lt 24h from power on or PO lees GPS contact for a poor GPS contact Jong tie oce DUE This message may Manual 010 Manual Hold over temporarily occur Hold over or selected by user during start up ON 9108 Temporar ily 10 Alarm ON GPS fail error occurred valid calibration or inthe GPS time data GPS receiver Locked to Frequency Disciplined mode No an P GPS ON offset There is tenna has been discon GPS contact Cali nected bration process is valid Ant Antenna over O Cur current Check for short circuited an tenna or cable 3 6 Indicators a Using the Controls Led Display Meaning Alarm ON Adj range Out of adjustment range Can no lon ger discipline local oscillator Try to dis connect reconnect the 910 910R If the error remains contact your local service center
39. age is at least 1 Vrms Verify that the pulse output has an amplitude of at least 3 Vpp 5 3 Front Panel Controls Performance Check The low level shall be 20 V but 0 9 V and the high level shall be gt 3 V but lt 5 V Connect a PM 6681R counter and verify that the fre quency is 10 MHz 0 01 Hz 5 MHz 0 005 Hz 1 MHz 0 001 Hz and 0 1 MHz 0 0001 Hz respectively Option 72 2 048 MHz Connect a DSO with 75 inputs to all BNC connectors one at a time Verify that the output signal voltage is 1 2V 0 12V Con nect a PM 6681R counter and verify that the frequency is 2 048 MHz 0 002 Hz Option 75 Pulse Output Connect a DSO with 50 Q inputs to the Optional Pulse Out BNC connector Verify that the voltage is a square wave and that the low level is lt 0 9 V and the high level gt 1 8 V Connect a PM 6681R counter and verify that the frequency is 1 Hz 1 uHz factory default setting is 1 Hz If the frequency has been changed via the GPSView SW then the mea sured frequency should be the nominal fre quency 1 ppm Test of PC Connection This test is only required if you intend to oper ate the 910 910R via a PC Connect the RS232 cable Start and run GPSView Select the correct COM port from the Jn strument Communication Port menu Select Connect and make sure you get no error messages Run the Self Test under the Instrument menu and mak
40. and X timescale lt Y zero gt and lt X zero gt are numerical values ASCII format indicating the start value for the X and Y values lt Y resolution gt and lt X resolution gt are numerical values ASCII format indicating the unit value of the data in the binary block e g 1E 10 for TIE saying that the data in the binary block should be multiplied with 100 ps TIE to obtain the actual value lt Samples gt is a numerical value ASCII format that equals the number of samples for TIE in the following binary block lt Max Y gt lt min Y gt lt max Y X gt and lt min Y X gt defines a boundary box for the trace data 8 14 Appendix 3 Command Reference Appendix The binary data contains TIE values together with the corresponding timestamp for these values Each value occupies 4 bytes of binary data in the 32 bit signed integer format in s c little endian format negative numbers as 2 complement That means that the binary data block size is 2 Samples 4 bytes stored in the order Y2 X2 etc The absolute value in seconds of TIE corresponding to the binary value Yi is calculated as Y Y resolution Y zero The absolute value in seconds since 00 00 00 on January 1 1980 ofthe timestamp corresponding to the binary value Xi is calculated as X X resolution X zero The relative timestamp value in seconds since first measurement is calculated as X X resolution first measurement has tim
41. and adjusted When using the received GPS signal for disci plining the stability is reduced for averaging times of 100s to 1000s The manual Hold over mode removes the auto matic adjustment thereby improving the short term stability This mode is intended for critical applications like jitter and wander mea surements where the frequency standard used must have an excellent short term stability The manual Hold over mode makes it possible to temporarily switch over from disciplined to Hold over mode during the actual measurement thereby achieving a superior frequency accuracy at the start of the measurement and a superior stability through the measurement Made for Portability When using manual Hold over mode the 910 910R acts like a stand alone OCXO or Ru bidium frequency standard This means that 910 910R are up and running after just 10 min utes after a change of location Best of Two Worlds The 910 and 910R have a unique design with a built in measurement kernel for continuous comparison of two independent frequency sources the received 1 signal from the GPS satellites and the very high stability in ternal oscillator Thanks to this design the very high stability built in Rubidium or OCXO oscillator is continuously calibrated and traceable to the primary frequency stan dards in the US Naval Observatory and ulti mately to all national standards e g NIST NPL PTB SP etc In the disciplined mode th
42. at the instrument complies to Query syntax SYSTem VERSion cnl Response format numeric value gt lt nl gt SEND gt SYSTem VERSion lt nl gt READ lt 1992 0 lt nl gt This instrument complies to version 1992 0 8 40 Appendix 3 Command Reference Appendix No antenna alarm enable SYST ALAR ENAB NOAN Purpose Enables disables the antenna alarm The alarm is enabled by default Some antennas may draw very low current which may be interpreted by the frequency standard as antenna If so disable the antenna alarm via this command Note The setting is stored in the non volatile memory Command syntax SYSTem ALARm ENABle NOANtenna ON OFF lt nl gt SEND gt SYSTem ALARm ENABle NOANtenna OFF lt nl gt Disables the no antenna alarm Query syntax SYSTem ALARm ENABle NOANtenna nl Response format 0 1 lt nl gt Example SEND gt SYSTem ALARm ENABle NOANtenna nl READ lt 0 lt nl gt The no antenna alarm is disabled Talk only mode SYST TALK Purpose Turning on the talk only mode causes the instrument to continously output the results of the primary measurements on the serial interface This means that once every 30 s there will be a message with format lt TIE gt lt X gt where TIE is the measured Time Interval Error and lt X gt is the timestamp of the measurement number of seconds since the first TIE measurement Example message READ l
43. boxes that can withstand the local cli matic conditions Coaxial Cables Used for transferring the HF signal from the antenna unit to the receiver sometimes via other system components Active de vices like line amplifiers and the antenna unit itself are also supplied with DC power through this cable Only high quality 50 Q cables should be used preferably RG 213 for normal use and LMR 400 when long distances have to be bridged m Coaxial Adapters Used for interconnecting system compo nents employing different connector stan dards major connector manufacturers also supply a large variety of adapters Note that most adapters require additional protection if mounted outdoors or in places with high hu midity m Line Amplifiers Used for compensation of cable losses Normally wide band amplifiers with moderate gain are used but in special cases tuned high gain amplifiers may be more suitable for example when very long cable lengths are nec essary Maximum two amplifiers can be inserted in the signal path before the loss seen from the an tenna exceeds 6 dB The distance between the antenna and the first line amplifier should be as short as possible and not more than about 35 m giving aloss of 35 0 17 6 dB ifa low loss ca ble is used If this basic rule is followed the noise figure of the total system is almost entirely set by the first amplifier stage in this case the active antenna
44. connect the serial ca FEL RUE if re ble connect the Ethernet cable between instru GSP ment and outlet hub controller Print Setup Pint Galibration TOO Make sure you use the right type of cable ac Set Usar Infomation cording to the instructions on page 2 8 1 D Stemp foobar gva 2 D Memp Esample qvp T 3 D temp Example gvh Establish the connection by selecting Instru vp Subs ment Connect on the menu bar e 4 4 The GPSView Screen GPSView m Update Database The database file default name Reference His tory receives new data from the connected in strument when Update database is selected The 24h mean frequency offset is fetched from the instrument s non volatile Archive data These values are kept for at least 2 years so it is sufficient to update the database once every second year for an ubroken chain of offset data However to get the associated uncertainty re corded as well it is recommended to update the database once a month The uncertainty for each 24h frequency offset value is calculated based on known uncertainty in the measurement kernel and the spread of the individual TIE values over that day The un certainty values are added to the database file when you execute the Update database COM MAND Note 1 Internally stored TIE values sampled every hour are kept for 40 days so it is recom mended to update the database once a month to obtain continuous uncertainty data
45. cts ROM test SEND gt TST lt nl gt Makes the selected test READ lt 0 lt nl gt Result from test 0 no error Query Syntax TEST SELect lt nl gt Response lt text gt SEND gt TEST SEL lt nl gt Asks what test is selected READ lt ROM lt nl gt The instrument is set up for ROM test m IEEE 488 2 defined commands standard commands Identification query IDN Purpose The identification query reads out the manufacturer model serial number and firmware level as an ASCii response data element The query must be the last query in a program message Query Syntax IDN nl Response syntax lt Manufacturer gt lt Model gt lt Serial Number gt lt Firmware Level gt lt nl gt Example SEND gt IDN lt nl gt READ lt Fluke 910 123456 V1 01 nl 8 21 Appendix 3 Command Reference Appendix Protected User Data PUD Purpose This is a data area in which the user may write any data up to 64 characters The data can always be read but you can only write data after unprotecting the data area A typical use would be to hold owner user name usage time inventory control numbers etc Query Syntax PUD lt nl gt Response syntax lt Arbitrary block response data gt lt nl gt where lt arbitrary block program data gt is the data last programmed with PUD Example SEND gt SYST UNPR PUD 240ACME Inc Bobby Brown inventoryNo 1234 lt nl gt means that lt arbitrary block program
46. curing the antenna unit At the same time the coaxial connectors are pro tected from both mechanical and environ mental influence Pipes with 1 14 UNS thread suitable as masts can often be obtained from retailers selling boat gear Fluke offers the accessory option 01 50 an antenna mounting kit for wall or pole mount ing 8 8 Appendix 1 Antenna Installation Appendix Appendix 2 Device Error Messages Ifthe frequency standard detects an internal er ror or an invalid setting it shows an error mes sage on the display This appendix lists all pos sible error messages Messages due to operation errors Rok D Curr Antenna current The antenna current is too high over current Check for short circuits or connect the antenna via a longer cable na AntEnnA Antenna current No antenna is recognized under current Check cable and connectors Try to disconnect reconnect the frequency standard Note some antennas may draw very low cur rent which may be interpreted by the frequency standard as antenna If so disable the antenna alarm via GPS View or via program ming code SYST ALAR ENAB NOAN GPS FR iL GPS receiver fail Internal error in the GPS receiver Try to disconnect reconnect the fre quency standard Adj Frequency adjust fail Can not control the local oscillator any longer Try to disconnect reconnect the frequency standard Hb unLac d Rb r
47. dditional local oscillator instabili ties for averaging times of 100 1000 seconds This is avoided by selecting manual Hold over Measurement Principle Every 30s phase difference the so called TIE Time Interval Error is measured between the lpps signal and the interval oscillator This phase difference is measured as the time interval between the zero crossings of the signals If there is a frequency offset from the nominal the TIE value time interval will increase or de crease between successive measurements E g if the TIE value 5ns at time 0 and is 15ns 10 000 seconds later then the corresponding differ ence in frequency is TIE 2 TIEQ _ 15 5ns _ 20 time 2 time 1 10000 0s 10000s 2 10712 The 910 and 910R calculate the frequency offset in just this way Multiple TIE value differences over longer time periods are used to calculate frequency offset over 24h between the local os cillator and GPS Note The frequency is very unstable during the first 5 10 minutes after power on of a cold unit Note The calculated 24 h frequency offset may be outside the specification during the first cou ple of days of operation 3 5 Functional Description a Using the Controls n d IC ato rs Led Display Meaning Locked to Time of Disciplined mode Led Display Meaning GPSON There is Manual __ Frequency Manual Hold over
48. de L1 C A Connector RJ45 Buffer RAM 1 kbit Antenna Option 01 Configuration port Standard RS232 port Type active L1 Fan Operating tem Temperature controlled perature 40 C to 70 C Height 81 mm 3 2 Environmental Data Weight 230 g 8 oz Gain gt 30 dB Connector TNC Temperature 0 50 operating 40 70 storage Humidity 95 RH 0 30 Antenna Cable Option 02 operating amp storage Altitude 4600 m operating 12000 m storage see Vibration 3G 55 Hz per Length 20m amp 50m MIL T 28800D Class 3 Connectors type N and TNC male Style D Attenuation B Q 1 6 GHz Shock Half sine 40G per Cable delay approx 5 05 ns m MIL T 28800D Class 3 Style D Bench handling Safety Compliant with CE PC Connection EN 61010 1 A1 1992 A2 1995 EMI Compliant with CE Interface RS232 DTE EN61326 1 1997 Connector 9 pin male DB9 Rx on pin2 Tx on pin 3 GND on pin 5 Baud rate 9600 bps Dimensions and Weight Data structure 8 data bits 1 stop bit no par WxHxD 315 x 86 x 395 mm Weight 910R 4 4 kg net 7 4 kg shipping 910 3 9 kg net 6 9 kg shipping 7 5 Frequency Stability w e Specifications Power Consumption Line voltage 90 264 V Line frequency 47 63 Hz Power 910R lt 75W at warm up lt 35W continuous opera tion Power 910 lt 25W at warm up lt 12W continuous opera tion Ordering Information 910 GPS OCXO freque
49. diting Marker Lines You can change the style and color of the marker line 20x10 s ae Edit selected graphical object Show date Undalastzcom Zoom out full Figure 4 5 edit the horizontal line click on Edit selected graphi cal object 4 11 Graphs in GPSView GPSView This page is intentionally left blank 4 12 Graphs in GPSView Chapter 5 Performance Check Performance Check General Information WARNING Before turning on the in strument ensure that it has been installed in accordance with the In stallation Instructions outlined in Chapter 1 of the Operators Manual This performance procedure is intended for in coming inspection to determine the acceptabil ity of newly purchased instruments Note The procedure does not check every facet ofthe instrument It is concerned primarily with those parts of the instrument which are essen tial for determining the function of the instru ment Note This GPS controlled Frequency Refer ence does not need to be sent away for fre quency calibration since the instrument is con tinuously calibrated via the GPS signal as long as there is a sufficient contact with the GPS satellites It is not necessary to remove the cover ofthe in strument to perform this procedure Recommended Test Equipment DSO with 50 Q input PM6681R timer counter 5 2 General Information Preparations Connect the ant
50. e calibration data 15 used to adjust the inter nal oscillator to fully compensate for the aging of the local oscillator 1 3 Preface 1 4 This page is intentionally left blank Chapter 2 Preparation for Use Preparation for Use Safety Instructions Introduction Read this page carefully before you install and use the instrument This instrument has been designed and tested ac cording to safety Class 1 requirements of EN61010 1 and CSA 22 2 No 1010 1 and has been supplied in a safe condition The user of this instrument must have the required knowl edge of it This knowledge can be gained by thoroughly studying this manual This instrument is designed to be used by trained personnel only Removal of the cover for repair or rack mounting of the instrument must be done by qualified personnel who are aware of the hazards involved There user serviceable parts inside the instrument Safety Precautions To ensure the correct and safe operation of this instrument it is essential that you follow gener ally accepted safety procedures in addition to the safety precautions specified in this manual Caution and Warning Statements CAUTION Shows where incorrect procedures can cause damage to or destruction of equipment or other property WARNING Shows a potential danger that requires correct procedures or practices to prevent personal injury 2 2 Introduction Symbols S
51. e media We will re place improperly recorded media without charge for 90 days after shipment upon receipt ofthe soft ware Our software is not guaranteed to be error free Fluke s obligation under this guarantee is limited to have repaired or replace a product that is re turned to an authorized Fluke Service Center within the guarantee period provided that Fluke de termines that the product is defective and that the failure has not been caused by misuse alteration or abnormal operation Guarantee service for products installed by Fluke will be performed at the Buyer s facility at no charge within Fluke s service travel area outside this area guarantee service will be performed at the Buyer s facility only upon Fluke prior agreement and the Buyer shall pay Fluke round trip travel expenses Ifa failure occurs send the product freight prepaid to the Service Center designated by Fluke with a description of the difficulty At Fluke s option repairs will be made or the product replaced Fluke shall return the product F O B Repair Center transportation prepaid unless the product is to be returned to another country in which case the Buyer shall pay all shipping charges duties and taxes Fluke assume NO risk for damage in transit Disclaimer The foregoing guarantee is exclusive and is in lieu of all other guarantees expressed or implied in cluding but not limited to any implied guarantee of merchantability fitness or adequacy for an
52. e sure you get no error mes sages 5 4 Test of PC Connection Test of Ethernet Connection This test is only possible if Option 76 has been installed If the interface has not been configured follow the instructions on page 4 4 Connect a cross wired Cat 5 patch cord between the instrument and a PC with Ethernet capability and the GPSView SW installed Start and run GPSView Make sure the interface selector on the rear panel is in position Ethernet Check the Use Ethernet box on the Instru ment Communication Port menu Ascertain that the IP address is the same as the one already configured Click OK and select Connect Make sure you get no error messages Run the Self Test under the Instrument menu and make sure you get no error messages Chapter 6 Preventive Maintenance Preventive Maintenance Calibration Calibration and adjustment in the traditional sense are not necessary as long as the instru ment is operating in the GPS disciplined mode Then the internal timebase Rubidium or OCXO is continuously monitored and forced to follow the cesium clocks of the GPS satel lites These clocks are traceable to NIST and USNO The deviation between the GPS timing signal and the built in local oscillator Rubid ium or OCXO is continuously measured and stored in non volatile memory By regularly transferring and appending the memory contents to a reference history archive file us
53. eceiver to enter Position Hold mode is significantly reduced NOTE Use this command only when the exact co ordinates are known Command syntax GPS POSition lt N S gt lt deg gt lt min gt lt sec gt lt E W gt lt deg gt lt min gt lt sec gt lt alt gt lt nl gt Parameters 0 Latitude deg 90 0 lt Longitude deg lt 180 0 x min lt 59 0 lt sec lt 597 999 1000 00 m x Altitude m cm 18000 00 m Note Latitude and longitude are expressed in degrees minutes seconds with decimals Altitude is expressed in meters with decimals NOTE 1 If wrong co ordinates are entered the 1pps timing accuracy is impaired NOTE 2 The position hold mode should be disabled command GPS POS HOLD STAT 0 before this command is given Query syntax GPS POSition lt nl gt Response format lt N S gt lt deg gt lt min gt lt s ms gt lt E W gt lt deg gt lt min gt lt sec ms gt lt h cm gt lt nl gt Note Latitude and longitude are expressed in degrees minutes seconds with 3 decimals Altitude is expressed in meters with 2 decimals Example SEND gt GPS POS lt nI gt READ N 31 41 59 141 E 14 21 47 210 23 11 lt nl gt In this example the position is as follows Latitude N 31 41 59 141 Longitude E 14 21 47 210 Altitude 23 11 m 8 28 Appendix 3 Command Reference Appendix Surveying satellites for position GPS POS SURV STAT Purpose Enables
54. ecognized data 130 Suffix error 102 Syntax error 131 Invalid suffix 103 Invalid separator 134 Suffix too long 104 Data type error 138 Suffix not allowed 108 Parameter not allowed 140 Character data error 109 Missing parameter 141 Invalid character data 110 Command header error 144 Character data too long 111 Header separator error 48 Character data not allowed 112 Program mnemonic too long 150 String data error 113 Undefined header 151 Invalid string data unexpected end of 114 Header suffix out of range message 120 Numeric data error 151 Invalid string data 120 Numeric data error overflow from 158 String data not allowed conversion 160 Block data error 120 Numeric data error underflow 161 Invalid block data from conversion 168 Block data not allowed 120 Numeric data error not a number 170 Expression data error from conversion 170 Expression data error different number 121 Invalid character in number of channels given 8 44 Appendix 4 Remote Error Messages Appendix Number Description 170 Expression data error floating point underflow 170 Expression data error floating point overflow 170 Expression data error not a number 171 Invalid expression data 171 Invalid expression data unrecognized expression type 171 Invalid expression data bad mne monic 171 Invalid expression data illegal ele ment 171 Invalid expression data unexpected end of message 178 Expr
55. ed array of TIE measurements frequency offset values based on these TIE measurements Query Syntax TRACe TIE DATA CH1 lt nl gt get 30 s TIE values array TRACe TIE TIE1H CHI get 1h TIE values array TRACE TIEJ DEVIH DEV24H ARC24H lt gt get frequency offset values array The TIE values array occupies max 8166 memory positions when taking 30s samples gt 2 days of data and max 1000 memory positions when taking 1h samples 740 days of data The 1h array is obtained by sub sampling the normal 30s array The sample during the first 30s after every full UTC hour is saved in volatile memory When the array is full the oldest samples are de leted to make room for new samples The RAM stored frequency offset values DEV1H DEV24H occupy max 720 values 27 days of data The archived 24h frequency offset values occupy approximately 1000 values 72 years of data at normal usage The TIE values array is updated once per 30s The RAM stored frequency offset values array DEV1H DEV24H is updated every 15 minutes and the archived non volatile storage 24h offset values array ARC24H is updated once per 24h Example SEND gt TRACe CH1 lt nl gt This example shows a request for TIE values array data 8 13 Appendix 3 Command Reference Appendix Response Syntax lt header gt lt binary block gt lt nl gt Binary block A binary block has the format ds lt binary data gt without the
56. ef unlocked Rubidium Timebase is un locked 5 minutes after power on 8 9 Appendix 2 Device Error Messages Appendix Appendix 3 Command Reference Remote control and programming reference for Fluke GPS Controlled Frequency Standards 910 910R First time Installation of the 910 910R Connect the 910 910R to the RS232 port of the computer using a suitable serial cable see page 2 8 Turn on the computer and the frequency stan dard Make sure that the communication settings for the RS232 port of the computer and the fre quency standard match The fixed settings ofthe frequency standard are as follows 9600 baud No parity 8 data bits 1 stop bit You can modify the computer RS232 port set tings to match the above frequency standard settings with the following DOS command MODE COM1 9600 N 8 1 This command assumes that COMI is the RS232 port used on the computer Replace COMI in the above command by COM2 CONG or COM4 if one of these ports is used Introduction to Programming m Basic Programming Information You can control the frequency standard from the computer with simple communication facil ities such as QuickBASIC and QBASIC pro 8 10 Appendix 3 Command Reference gramming languages from Microsoft Corpora tion m Example Language Small examples are given at various places in the text These examples are not in BASIC or C nor are they written for any specific controller They onl
57. enna including cable to the an tenna input rear Power On Test Connect the power cord At power on the fre quency standard performs an automatic test of the following RAM ROM Measuring circuits GPS receiver If any test fails an error message is shown Power up your instrument at least 30 minutes before continuing This will allow the instru ment to reach normal operating temperature and go into GPS locked mode Performance Check Front Panel Controls Keyboard and Indicator Test The display back light shall be lit when the instrument is connected to the power outlet 2 a Press manual Hold Over key The man ual Hold Over LED shall be turned ON b The Locked to GPS LED shall be turned OFF 3 a Press manual Hold Over key again The manual Hold Over LED shall be turned OFF b Make sure that Locked to GPS is turned ON It may take up to 30 s 4 Disconnect the antenna The alarm diode shall be turned ON and Locked to GPS shall be turned OFF after 1s The satellite signal shall disappear within 30s 5 Reconnect the antenna The alarm diode shall be turned OFF The satellite signal strength indicator shall reappear and Locked to GPS shall be turned ON within 30s Frequency Offset Calculation Test After 24h the first calculated frequency offset value shall be displayed Note this first offset value may be far from the specification After 48h the frequency offset value
58. er interrupt the grounding cord Any interruption of the protective ground connection inside or outside the instrument or disconnection of the protective ground terminal is likely to make the instrument dangerous 2 3 Grounding Preparation for Use Unpacking Unpacking Instructions Check that the shipment is complete and that no damage has occurred during transportation If the contents are incomplete or damaged file a claim with the carrier immediately Also notify your local Fluke sales or service office in case repair or replacement may be required Check List The shipment should contain the following The frequency standard Line cord GPSView program disk This Operators Manual If you ordered one of the options 70 71 72 and or the options 75 76 they should al ready be installed See Identification be low Other options you ordered e g antenna option 01 antenna cable option 02 rack mount kit PM9622 or carrying case PM9627 are shipped in separate boxes Certificate of Calibration Identification Options installed inside the cover are identified on the rear panel according to the list below Option 70 5 BNC connectors mounted in the area designated Optional 10 MHz Outputs Option 71 5 BNC connectors mounted in the area designated Option 71 Outputs 2 4 Unpacking Instructions Option 72 5 BNC connectors mounted in the area d
59. esignated Option 72 Outputs Option 75 1 BNC connector mounted in the area designated Optional Pulse Output Option 76 1 RJ45 Ethernet connector to the right of the antenna input 1 switch desig nated Ethernet RS232 to the left of the RS232 connector Preparation for Use Installation Supply Voltage Setting The GPS frequency standard may be connected to any AC supply with a voltage rating of 100 to 240 Vims 47 to 63 Hz The frequency standard automatically adjusts itselfto the input line volt age Fuse A 1 6A 250V slow blow fuse is placed inside the frequency standard This fuse rating is used for the full voltage range CAUTION If this fuse is blown it is likely that the power supply is badly damaged do not replace the fuse Send the frequency standard to the local Fluke Service Center Grounding Grounding faults in the line voltage sup ply will make any instrument connected to it dangerous Before connecting any unit to the power line you must make sure that the protective ground functions correctly Only then can a unit be connected to the power line and only by using a three wire line cord No other method of grounding is permitted Exten sion cords must always have a protective ground conductor WARNING If a unit is moved from a cold to a warm environment con densation may cause a shock hazard Ensure therefore that the grounding requirements are strictly me
60. ession data not allowed 180 Macro error 181 Invalid outside macro definition 183 Invalid inside macro definition 184 Macro parameter error 184 Macro parameter error parameter count mismatch 184 Macro parameter error unused pa rameter 184 Macro parameter error badly formed placeholder 200 Execution error 201 Invalid while in local 202 Settings lost due to rtl 210 Trigger error 211 Trigger ignored 213 Init ignored 214 Trigger deadlock 220 Parameter error 221 Settings conflict invalid combination of channel and function 221 Settings conflict 221 Settings conflict PUD memory is pro tected 222 Data out of range Save recall mem ory nr 8 45 Number Description 222 Data out of range exponent too large 222 Data out of range 222 Data out of range above maximum 222 Data out of range requires attenu ator on 222 Data out of range below minimum 223 Too much data PUD string too long 223 Too much data String or block too long 223 Too much data 224 Illegal parameter value 230 Data corrupt or stale 231 Data questionable one or more data fields ignored 231 Data questionable 240 Hardware error 241 Hardware missing 250 Mass storage error 251 Missing mass storage 252 Missing media 253 Corrupt media 254 Media full 255 Directory full 256 File name not found 257 File name error 258 Media protected 260 Expression error 261 Math error
61. estamp value zero Fetch data array 1h or 24h freq offset RAM TRACe DEV1H TRACe DEV24H Query syntax TRACE DEV1H DEV24H CH1 lt nl gt Response Syntax lt Channel gt lt Y unit gt lt X unit gt lt Y zero gt lt X zero gt lt Y resolution gt lt X resolution gt lt Re served gt lt Samples gt lt binary block gt lt nl gt Channel is a string and is either Channel 1 or No trace acquired in the latter case the rest of the response message does not contain valid data but is present lt Y unit gt and lt X unit gt are strings empty string for DEVIH and DEV24H s for X i e timestamps lt Y zero gt and lt X zero gt are numerical values ASCII format indicating the zero level value for the X and Y values lt Y resolution gt and lt X resolution gt are numerical values ASCII format indicating the unit value ofthe data in the binary block e g 1E 13 for y DEV1H or DEV24H saying that the data in the bi nary block should be multiplied with 1 10 relative frequency deviation Samples is a numerical value ASCII format that equals the number of samples for DEV1H or DEV24H in the following binary block The binary data contains DEV1H or DEV24H values together with the corresponding timestamp for these values Each value occupies 2 bytes of binary data in the 16 bit signed integer format in s c little endian format negative numbers as 2 complement That means that
62. et Instrument type If you check the save setting box the setting will be stored in non volatile memory other wise in volatile memory only Edit Menu Copy the selection and put it on the clipboard 4 7 The GPSView Screen a wp GPSView View Menu Window Menu Toolbar show or hide the New window open another window for toolbar the active document Status bar show or hide the sta Cascade arrange windows so they tus bar overlap Zoom out full zoom out to full Tile arrange windows as graph display non overlapping tiles Undo last zoom undo the last zoom Arrange icons arrange icons at the bot tom of the window vis New Window v Status grouped px Cascade Zoom out full Tile Undo last zoom Arrange Icons v 1 foobar gva Help Menu Help topics list help topics About GPS View display program in formation version number and copy right About instrument display instrument in formation Help Topics About GPSView AGout Instrument 2 4 8 The GPSView Screen a GPSView m GPSView TIE 1 h Graphs in GPSView nad This graph shows TIE over time with samples Deliberate disturbance for educational reasons taken every 60 min A sa ma X Filename Extensions mn GVA GPSView Archived AWAY Baa ex i coe D m GVH GPSView Hour Offset M This graph show
63. et date Make self test SSYST ERR WAI Error code and explanation of bus commands Wait to Continue command SYST KLOC Locks the keyboard to prevent user intervention when the frequency standard is under program control 8 43 Appendix 3 Command Reference Appendix Appendix 4 Remote Error Messages This appendix lists all possible error codes in the frequency standards Note that the list below is a generic list of error messages that can occur in SCPI instruments Not all type of listed errors can occur in the 910 or 910R frequency standards You read the error queue with the SYSTem ERRor query Example SEND gt SYSTem ERRor READ 100 Command Error The query returns the error number followed by the error description If more than one error oc curred the query will return the error that occurred first When you read an error you will also re move it from the queue You can read the next error by repeating the query When you have read all errors the queue is empty and the SYSTem ERRor Query will return 0 No error When errors occur and you do not read these errors the Error Queue may over flow Then the instrument will overwrite the last error in the queue with 350 Queue overflow If more errors occur after that they will be discarded 0 No Error 123 Exponent too large 100 Command error 124 Too many digits 101 Invalid character 128 Numeric data not allowed 102 Syntax error unr
64. gt lt Integer gt 128 Bit 7 64 Bit 6 32 Bit 5 16 Bit 4 8 Bit 3 4 Bit 2 2 Bit 1 1 Bit 0 Example Status Not used Not used A command error has occurred An execution error has occurred A device dependent error has occurred A query error has occurred Not used Operation complete SEND gt ESR lt nl gt READ lt 4 lt nl gt In this example a query error has occurred 8 24 Appendix 3 Command Reference Appendix Clear Status command CLS Purpose The CLS command clears the status data structures by clearing all event registers and the error queue It does not clear enable registers It clears any pending WAI OPC and OPC Command Syntax CLS lt nl gt Example SEND gt CLS lt nl gt Standard event status enable ESE ESE Purpose Sets and Reads out the contents of the standard event status enable register Command Syntax ESE lt dec data gt lt nl gt lt dec data gt the sum between 0 and 255 of all bits that are true lt Integer gt Status 128 Bit 7 Not used 64 Bit 6 Not used 32 Bit 5 Command error event enable 16 Bit 4 Execution error event enable 8 Bit 3 Device dependent error event enable 4 Bit 2 Query error event enable 2 Bit 1 Not used 1 Bit 0 Operation complete event enable Example SEND gt ESE 33 lt nl gt In this example the Command Error bit 5 and Operation Complete bit 0 enable bits are set Query
65. gt the sum of all bits that are true lt nl gt Event Register Bit 14 Rubidium oscillator un locked Value 16384 Bit 13 Out of adjustment range Value 8 192 Bit 12 No antenna Value 4096 Bit 11 Antenna over current Value 2048 Bit 10 GPS failure Value 1024 Bit 9 Measurement time out Value 5 12 Bit 8 Measurement stopped Value 256 Bit 5 Waiting for trigger and or external alarming Value 32 Bit 4 Measurement started Value 16 Other bits not used Example SEND gt STAT OPER lt nI gt READ lt 256 nl In this example status indicate that the measurement is stopped 8 18 Appendix 3 Command Reference Appendix Read status Purpose Read status operation condition register Query Syntax STATus OPERation CONDition lt nl gt Returned Format lt Decimal data gt lt nl gt lt dec data gt the sum of all bits that true lt nl gt Condition Register Bit 14 Rubidium oscillator un locked Bit 13 Out of adjustment range Bit 12 No antenna Bit 11 Antenna over current Bit 10 GPS failure Bit 9 Measurement time out Bit 8 Measurement stopped Bit 5 Waiting for trigger and or external alarming Bit 4 Measurement started Other bits not used Example SEND gt STAT OPER COND lt nl gt READ 4096 lt 1 gt STAT OPER COND Value 16384 Value 8192 Value 4096 Value 2048 Value 1024 Value 512 Value 256 Value 32 Value 16 In this example
66. he following tasks Transfer of archived data from non volatile memory in Model 910 910R 24h frequency offset values updated once per 24 h 2 years of data with normal us age daily adjustment control voltage values 2 years of data Transfer of stored data from volatile memory in Model 910 910R lh frequency offset values updated every 15 minutes approx 1 week of data 24h frequency offset values updated ev ery 15 minutes approx week of data phase deviation every 30 s approx 2 days of data phase deviation every 60 min approx 40 days of data 4 2 Introduction Transfer of control commands to Model 910 910R setting display option time of day or fre quency offset setting the pulse output period and width opt 75 setting instrument parameters toggling between Hold over or Disciplined mode local lockout of front panel buttons performing internal self tests Graphical display x t graphs 24h frequency offset vs time frequency history adjustment history phase deviation every 30 s volatile data phase deviation every 60 min vol data 1h frequency offset volatile data 24 h frequency offset volatile data Text display of GPS status e g no of satellites status position etc time of day UTC time time zone correc tion Print out of traceable calibration protocol any graph
67. hows where the protective ground ter inal is connected inside the instrument Never remove or loosen this screw ih Indicates that the operator should con ult the manual If in Doubt about Safety Whenever you suspect that it is unsafe to use the instrument you must make it inoperative by doing as follow Disconnect the line cord Clearly mark the instrument to prevent its further operation Inform your local Fluke Service Center For example the instrument is likely to be un safe if it is visibly damaged Fuse A 1 6A 250V slow blow fuse is placed in the internal power supply CAUTION If this fuse is blown it is likely that the power supply is badly damaged Do not replace the fuse Send the instrument to your local Service Center Grounding Whenever an instrument is connected to the line voltage a grounding fault will make it po tentially dangerous Before connecting any unit to the power line you must make sure that Preparation for Use the protective ground functions correctly Only then can a unit be connected to the power line and only by using a three wire line cord No other method of grounding is permitted Exten sion cords must always have a protective ground conductor WARNING If a unit is moved from a cold to a warm environment con densation may cause a shock hazard Ensure therefore that the grounding requirements are strictly met WARNING Nev
68. icating whether or not the device completed the selftest without any detected errors Use TEST SEL to select which test to run Query Syntax TST lt nl gt Example SEND gt TST lt nl gt Returned Format lt Integer gt lt nl gt where lt Integer gt a number indicating errors according to the table below lt Integer gt Error 0 No error 4 RAM Failure 8 ROM Failure 16 Non Volatile memory error 32 GPS Failure Status and Event commands Status byte query STB Purpose Status Byte Query Reads out the value of the Status Byte Query Syntax STB lt nl gt Returned Format lt Integer gt lt nI gt the sum between 0 and 255 of all bits that are true See table below 8 23 Appendix 3 Command Reference Appendix lt Integer gt Status 128 Bit 7 Measurement started 64 Bit 6 Master Summary Status 32 Bit 5 A bit in the standard event status register is set 16 Bit 4 Message available always set 8 Bit 3 Not used 4 Bit 2 Error available 2 Bit 1 Not used 1 Bit 0 Not used Example SEND gt STB lt nl gt READ lt 16 lt 1 gt In this example a message is available Event status register Purpose Reads out the contents of the standard event status register Reading the Standard Event Status Register clears the register Query Syntax ESR lt nl gt Returned Format lt dec data gt the sum between 0 and 255 of all bits that are true lt nl
69. ice Request Query Syntax SRE nl 8 26 Appendix 3 Command Reference Appendix Returned Format lt dec data gt the sum between 0 and 255 of all bits that are true lt nl gt Example SEND gt SRE nl READ lt 32 nl In this example only the query error enable bit is set Wait to Continue Command WAI Purpose The wait to continue command prevents the frequency standard to execute any further commands and queries until all previous commands or queries has been completed Command Syntax lt command gt WAI lt command gt m GPS receiver settings and queries Position Hold mode GPS POS HOLD STAT Purpose Enables or disables Position Hold mode for the GPS receiver Command syntax GPS POSition HOLD STATe 0 1 lt nl gt 0 or OFF Position hold mode disabled 1 or ON Position hold mode enabled Query syntax GPS POSition HOLD STATe lt nI gt Response format 0 1 lt nl gt Note 1 Position Hold mode is TRUE 0 Position Hold mode is FALSE Example SEND gt GPS POS HOLD STAT lt nl gt READ 1 lt nl gt The GPS receiver has entered position hold mode in this example 8 27 Appendix 3 Command Reference Appendix Antenna position GPS POS Purpose This command will enable the GPS receiver s Position Hold mode with the co ordinates of the antenna given in the command By sending this command the position survey mode is skipped and the time it takes for the r
70. ile memory 740 days of data vol atile memory Inhibits automatic GPS adjustments and forces hold over opera tion LED Indicators Locked to GPS ON OFF Alarm ON OFF Disciplined mode Hold over mode Alarm condition reported by instrument hardware Explaining text in 7 segment display area Once lit the LED re mains lit as long as the cause for alarm is pres ent Normal operation 7 4 Frequency Stability Manual hold over ON OFF Forced hold over mode If GPS signal is valid the Frequency offset is displayed Otherwise 910 or 910R is shown Disciplined or hold over mode depending on Locked to GPS status Display Indicators 7 segment area 24h mean fre quency offset Time of day 910 910R send test If valid data exist if GPS contact gives valid time if GPS contact not suffi cient if instrument is transmit ting data to a PC if instrument is perform ing a self test Alarm text plus Alarm LED Antenna current GPS receiver fail Freq adjust fail Rb ref unlocked Ant O_Curr no AntEnnA GPS fail Adj range Rb unloc d REMOTE segment Local Lockout from Analog bar graph PC Satellite signal strength Specifications GPS Receiver Ethernet Connection Option 76 Antenna connector Type N Channels 8 parallel tracking Interface Ethernet 10Base T Carrier co
71. ing the GPSView PC software you can maintain a record of an unbroken chain of mea surements for an indefinite time Use the Up date database command for this purpose The database file must be updated every 2nd year to maintain a continuous day by day re cord of the frequency offset To maintain continuous uncertainty values as well the database should be updated every month It is possible to update and or print out the con tents of the archive file at any time to demon strate the current calibration status as well as the reference history You cannot claim trace ability without producing legible and continu ous records of frequency offset but it is up to you to decide the level of uncertainty Calibration intervals Normally it is quite adequate to update the ar chive file once every two years but since it is often easier to have annual routines unless they are computer controlled we recommend to up date once a year Database update intervals of 40 days or less also mean an unbroken chain of calculated un certainty values 6 2 Calibration m Procedure Note The procedure describes calibration over one of the standard RS232 COM ports but you may just as well use the Ethernet interface if Option 76 has been installed Connect the RS 232 port on the instrument to a free COM port on a PC with the GPSView software installed Start GPSView Identify the COM port number and select the corresp
72. is is a typical two amplifier configuration A worst case calculation using a LMR400 cable gives Antenna gain 36 dB Amplifier gain 40 dB 20 20 Cable loss 55 dB 325 0 17 Guard band 3 dB Harsh weather 6 dB Total gain 12 dB 36 40 55 6 3 In other words 325 m is close to the upper limit of the cable length if the weather conditions are much worse than average Otherwise you could expect another 35 m It is not recommended to cascade more than two amplifiers to obtain even greater cable lengths due to the risk of sat uration or other non linear behavior If need be use a single tuned amplifier designed for the calculated total gain Since the cable length outside the building is substantial it is strongly recommended to use a lightning arrester even if the location of the an tenna is well protected from direct lightning strikes Induced high voltages must not be ne glected Sensitive equipment without over voltage protection can easily be destroyed in this way Appendix Auxiliary Components on the Market This is a summary of system components that may be necessary to complete an installation tailored to your individual needs These com ponents are supplied by a large number of man ufacturers worldwide If any of these parts have to be mounted out doors make sure they have an adequate tem perature range They must also be specified as weatherproof Otherwise they have to be housed in
73. itself The noise of the line amplifiers can then normally be neglected Power Splitters Used for dividing the signal from the an tenna between two or more timing receiv ers There are both passive and active splitters the latter often being line amplifiers with more than one output A passive power splitter has a fixed insertion loss for instance 6 dB with the resis tive type whereas the active types often have no loss or even a low gain m Attenuators Used for adapting the signal level at the input of the receiver input There are both fixed and variable attenuators available m Lightning Arresters Passive devices for diverting over voltages to ground thus protecting sensitive equip ment connected to the output of the light ning arrester Such a device should be mounted inside the building close to the cable entry point It re quires a good ground connection through a 4 AWG copper wire or a braided copper strap 8 7 Appendix 1 Antenna Installation Appendix with the corresponding cross section area It must be a minimum cable length of 8 m after the lightning arrester to guarantee its proper function Remember that the antenna and the lightning arrester primarily protect the equipment later in the chain They may be destroyed themselves Consequently it is recommended to keep these components as replacement parts if minimum downtime is important m Mounting Masts Used for se
74. l gt READ lt 61 lt nI gt A leap second will be inserted at the leap time m Display commands Display feed DISP TEXT FEED Purpose To set or query the primary display feed This determines what data will be fed to the display if available Command Syntax DISPlay WINDow TEXT FEED DEV24 TIME lt nl gt The options are DEV24 for 24h frequency deviation and TIME for current time Query syntax DISPlay WINDow TEXT FEED lt nl gt Response format DEV24 TIME lt gt Example SEND gt DISPlay TEXT FEED lt gt READ DEV24 lt nl gt In this case the 24h frequency deviation is shown on the display if it is available 8 39 Appendix 3 Command Reference Appendix Save display feed DISP TEXT FEED SAVE Purpose To save the current display feed setting in non volatile memory Command Syntax DISPlay WINDow TEXT FEED SAVE lt nl gt Example SEND gt DISPlay TEXT FEED SAVE nl READ lt nl gt Restore display feed DISP TEXT FEED REST Purpose To restore the display feed setting from non volatile memory Command Syntax DISPlay WINDow TEXT FEED RESTore lt nl gt Example SEND gt DISPlay TEXT FEED REST lt gt READ nl Display feed is restored to the value last saved in non volatile memory factory default is DEV24 m System commands SCPI version query SYST VERS Purpose Returns a numeric value corresponding to the SCPI version number th
75. lt nl gt READ lt 1999 11 29 16 20 7 N 59 22 17 912 E 17 51 10 597 60 27 0 0 0 1 10 5 29 0 0 0 8 8 42 170 9 8 45 170 5 8 42 170 4 0 0 0 24 8 37 170 30 8 45 170 7 0 0 40 8 lt nl gt Predicted visible satellite Ds GPS SAT VIS PRED Purpose Retreives the satellite IDs of predicted visible satellites Query syntax GPS SATellite VISible PREDicted lt nl gt Response format lt list gt lt nl gt Note lt list gt Returns zero if there are no satellites visible and during start up Example SEND gt GPS SAT VIS PRED lt nl gt READ lt 6 8 13 14 17 21 23 lt nl gt Predicted visible satellite count GPS SAT VIS PRED COUN Purpose Retreives the number of predicted visible satellites Query syntax GPS SATellite VISible PREDicted COUNt lt nl gt Response format numeric data gt lt nl gt Example SEND gt GPS SAT VIS PRED COUN lt nI gt READ 11 lt nl gt 8 31 Appendix 3 Command Reference Appendix Predicted visible satellite data GPS SAT VIS PRED POS Purpose List of predicted visible satellite positions Query syntax GPS SATellite VISible PREDicted POSition lt nl gt Response format n ID d e a h nl satellite info is listed n times Data from maximum 12 satellites n number of visible sats ID satellite ID 1 32 d doppler frequency in Hz 5000 5000 e elevation in degrees 0 90 azimuth in degrees 0 359 h sat health 0 healthy a
76. mp not removed 1 healthy amp removed 2 unhealthy amp not removed 3 unhealthy amp removed Note The number of visible satellites may be more than 12 but there will only be data from maxi mum 12 satellites Example SEND gt GPS SATellite VISible PREDicted POSition lt nI gt READ 12 4 1214 31 83 0 5 41 82 177 0 6 3733 8 210 0 7 3322 13 49 0 8 3812 21 142 0 9 3092 40 154 0 14 816 11 5 0 16 2634 0 42 0 24 3137 19 125 0 25 3623 1 310 0 29 856 36 272 0 30 2706 43 259 0 lt nI gt In this example there are 12 predicted visible satellites with IDs number 4 5 6 7 8 9 14 16 24 25 29 and 30 8 32 Appendix 3 Command Reference Appendix Setting antenna delay time GPS REF ADEL Purpose Set delay time for used antenna cable Command syntax GPS REFerence ADELay delay time gt lt nl gt Note delay time gt numeric data is expressed in seconds with Ins resolution The value setting is stored in non volatile memory Example SEND gt GPS REF ADEL 101E 9 lt nl gt In this example the delay value for the option 02 antenna cable 20 m coaxial RG213 cable is en tered i e 101 ns d DE GPS REFerence ADELay lt nl gt Response format lt numeric data gt lt n gt 1 pps signal status GPS REF VAL Purpose Retrieves validity of 1 pps signal of the GPS receiver Query syntax GPS REFerence VALid lt nl gt Response format 0 1 lt nl gt Example SEND gt GPS REFerence
77. ncy standard 5 x 10 MHz 1 x 5 MHz and 1 x 1 outputs 910R GPS Rubidium frequency standard 5 x 10 MHz 1x 5 MHz and 1 x 1 outputs Opt 70 5 extra 10 MHz outputs Opt 71 5 extra outputs 1X 10MHz 1x5MHz IxIMHz 1x0 1MHz sine wave 1x0 1 MHz square w Opt 72 5 extra 2 048 MHz outputs Opt 75 1 extra pulse output 0 5 Hz 10 MHz Opt 76 Ethernet interface None of the options above is retrofittable and options 70 71 and 72 are mutually exclusive Included Accessories Operators manual Calibration certificate GPSView SW 7 6 Ordering Information Optional Accessories PM9622 19 rack mount kit PM9627 Carrying case PM9627H Heavy Duty Hard Transport Case Option 01 GPS antenna Option 01 50 Antenna mounting kit Option 02 Antenna cable 20m Option 02 50 Antenna cable 50m Chapter 8 Appendix Appendix Appendix 1 Antenna Installation Introduction When installing antenna for the GPS controlled frequency standards 910 or 910R some basic facts should be considered relating to antennas and radio reception proper ties The theoretical and practical discussions below will help you to make the right decisions Fluke supplies a GPS antenna option 01 and a cable assembly option 02 Other system com ponents that may be necessary to fulfil your re quirements are readily available from vendors of GPS antenna equipment It is important to observe that deviation
78. ng over Internet is thus a simple task Standard Cat 5 patch cords of good quality with RJ45 connectors can be used Note There are two types available straight through and cross wired The first one is used when connecting to a wall outlet or a hub the second one when connecting directly to a PC or other controller Chapter 3 Using the Controls Using the Controls Basic Controls Display of the relative mean frequency offset during the last 24h This offset is recalculated every 15 minutes To obtain the frequency offset value in Hz multiply the display value with 10 MHz 1077 Hz E g 1 7 E 107 dis played means an offset of 1 741092 1 10 7 1 7 10 17pHz REMOTE indicates that the front panel operation is locked out Manual Hold Over key tog gles manual Hold over mode on off In Hold over mode GPS disciplining is disabled resulting in an improved short medium term stability Indicates status of Manual Hold Over 909 FREQUENCY STANDARD 1 ie REMOTE RUBIDIUM ATOMIC CLOCK Satellite Signal Strength 7 X Locked to GPS Alarm indicator warns of e g internal instrument errors GPS receiver er rors or antenna discon nection An error mes sage is always displayed in the 7 segment display area A 21 segment bar graph dis play showing combined satel lite signal strength The unit will operate
79. onding number under the n strument Communication Port menu Connect instrument and PC by selecting Connect under the nstrument menu Under the File Menu select Set User Infor mation and check the contents Change if required This information will be printed on the calibration records Under the File Menu choose Select Data base and then Reference History If there are history data present from ear lier calibrations print the file contents by selecting Print Calibration Protocol as a precaution Select Update Database to append new data to the Reference History It may take a few minutes Check the contents by selecting Print Cali bration Protocol again Now you should have a new valid calibration record ready for filing Select Close Database Preventive Maintenance Fan Replacement If your frequency reference is operating 24h day you need to replace the fan every 5 years to maintain high reliability For part time applications and low ambient temperatures an extended service interval is acceptable Fan replacement requires no special tools screwdrivers only The part number of the re placement fan is 5322 361 10539 6 3 Fan Replacement Preventive Maintenance 6 4 Fan Replacement This page is intentionally left blank Chapter 7 Specifications ah v Specifications Technical Specification 910 910R GPS controlled Frequency Standard
80. opy the underlying graph data to e g a spreadsheet program like Excel then point at curve right click your mouse select the show underlying data watch the table of numeric data pop up and finally select After that switch to your spreadsheet program and paste the data into your spread sheet Copy Format Y 1 768e 07 lll 1 52e 07 1 48e 07 1 825e 07 1 47e 07 1 679e 07 2 207e 07 2 223e 07 1 52 07 1 794e 07 2 369e 07 1 987e 07 1 946e 07 2 108e 07 2 008e 07 ha 0 1 2 3 4 5 6 7 8 Figure 4 1 Shows underlying data 4 10 Graphs in GPSView m Edit Graphs You can e g change the style and color of the graph lines ak Edit selected graphical object Show underlying data Undo last zoom Zoom out full Figure 4 2 To edit the graph click on Edit selected graphical ob ject m Edit the Y axis You can e g change the scale markers and add horizontal marker lines t Edit selected graphical object Ghow ungenving date Undo last zoom Zoom out full 4 0x10 77 Figure 4 3 edit the y axis click on Edit selected graphical ob ject m Edit the X axis You can e g change the scale markers and add vertical marker lines 40x10 0 Edit selected graphical object Show underving data Undo last zoom Zoom out full Figure 4 4 edit the x axis click on Edit selected graphical ob ject GPSView m E
81. quotes Mandatory first character of binary block d the first character after the tells the number of digits in the block size number s the block size that is s bytes of binary data will follow The value of s contains d characters Example 217actually a lt gt In this example the block size number has 2 digits the block size is 17 and the following 17 charac ters is the data which in this example is no binary number but a string for the sake of visibility Bi nary data are most commonly not printable An empty block is written 10 Header A header consists of several parameters both strings and numerical values in ASCII format Strings ee are written within double quotes i e Hz Strings may be empty i e Fetch data array TIE TRACe TIE Query Syntax TRACe TIE DATA CH1 lt nl gt get 30 s TIE values array TRACe TIEJ TIETH CHI get 1h TIE values array Response Syntax lt Channel gt lt Y unit gt lt X unit gt lt Y zero gt lt X zero gt lt Y resolution gt lt X resolution gt lt Re served gt lt Samples gt lt max Y gt lt min Y gt lt max Y X gt lt min Y X gt lt binary block gt lt nl gt Channel is a string and is either Channel 1 or No trace acquired in the latter case the rest of the response message does not contain valid data but is present lt Y unit gt and lt X unit gt are strings s for both Y TIE
82. s Frequency Stability Frequency Stability Locked Frequency Stability to GPS Hold over Mode 910R 910 910R 910 Frequency offset lt 1x10 1 lt 2x10 7 Aging 24h lt 2x10 7 lt 1x10 24h mean Short Aging month 5x10 lt 3x10 term Allan dev Temp 0 C 50 C lt 3x10719 lt 2 5x10 x 1000 s lt 1 10 lt 5x10 1 Temp 23 3 2x10 lt 4x10 10 x 100 s lt 3 1012 lt 3x10 Short term Allan 10 s lt 1x10 5x19 dev v2 15 lt 3x10 lt 5x10 x 100 s 3x10 2 3x19 x 10 s 1x10 5x19 2 15 3x10 5x19 Warm up time to lock at 25 lt 20 min lt 20 min Warm up 25 t 423413 C 10 min to 4x101 5x19 typical after 14 days of continuous operation Phase Noise 910R 910 1 Hz 80 100 dBc Hz typ 10 Hz 90 120 dBc Hz typ 100Hz 130 130 dBc Hz typ 1 kHz 140 135 dBc Hz typ 10kHz 140 135 dBc Hz typ 100kHz 145 135 dBc Hz typ 2 7 2 Frequency Stability wy Specifications Standard Reference Outputs Option 72 Outputs Connector type BNC Frequency 2 048 MHz square wave 10 MHz Sine wave gt 0 6V rms in 50 Output level 1 2V to 1 2V 10 in 75 2 5 MHz Sine wave gt 0 6V rms in 50 G 703 10 Freq Stability See frequency stability specs Freq Stability See frequency stability specs for 910 resp 910R for for 910 resp 910R for GPS locked respectively GPS locked resp hold over hold over
83. s from the recommended normal solution may se verely impair the performance of the overall system unless the user has acquired the knowl edge necessary to design a configuration of his own General guidelines to good system design are given in this section of the handbook but the user is entirely responsible for adequate per formance in this case Available Options for Antenna Installation Option 01 GPS antenna w Type TNC fem Conn Option 01 50 Antenna mounting kit for wall or pole mounting Option 02 Antenna cable 20 m or 50 m with Type TNC male connec tor at one end and Type N male at the other 8 2 Appendix 1 Antenna Installation General Guidelines to Good Antenna Location The general rule that applies to all installations working in or near the microwave frequency bands is that it should be possible to see the transmitter from the receiver antenna position When dealing with terrestrial radio communi cation it is a great advantage to place both the transmitter antenna and the receiver antenna as high as possible The effective line of sight dis tance increases with the square root of the height above ground The satellite based GPS transmitters are how ever moving targets in the sky and require in part new rules of thumb Moreover you need at least see more than two satellites simulta neously irrespective of the point of time to get stable time readings The receiver can have contact with eigh
84. s further specified Do not insert the brackets in the command Fal The item between these brackets is optional This means that you may omit it Do not insert the brackets in the command This is a separator between selectable items This means that you must choose only one of the items exclusive or Example 1 2 means you can type either 1 or 2 Overview of Command Subsystems FETCh Requests the instrument to return a measuring result TRACE Requests the instrument to return an array of measured values SOURce Selects output signal period and pulse width STATus This subsystem can be used to get information about what is happening in the instrument at the moment SYNChronization This subsystem can be used to view GPS synchronization SYSTem This subsystem controls some system parame ters GPS This subsystem controls the GPS receiver and retrieves status info TEST This subsystem tests the hardware and software of the frequency reference and reports errors PTIMe 8 11 Appendix 3 Command Reference Appendix This is for compatibility with other references OUTPut Show optional pulse output status m Program Sequence A typical program sequence consists of the fol lowing user actions 1 Set the communication parameters for the RS232 port of the computer to match the fre quency standard settings 2 Output a command or query or a list of com mands and queries to the frequency standard In some
85. s the relative frequency offset um 1 h average over time 5 This is a file containing the archived frequency offset data and the archived adjustment data The data is saved up to four years whereupon the first two years are erased and replaced by PT two new years This file displays the relative ps frequency offset 24 h average over time and Pee the relative aging adjustment over time LM m GVP GPSView TIE 30 s mi bu This graph shows the phase deviation or TIE Time Interval Error over time with samples m GVD GPSView Day Offset takeni even 30 This graph shows the relative frequency offset 24 h average over time 5 4 9 Graphs in GPSView 2 GPSView m Zooming in Graphs To zoom in a graph hold down the left button on your mouse and drag the pointer When you release the button the selected area will be zoomed You can undo the last zoom if you right click and choose Undo last zoom or you can zoom to the full graph display if you choose Zoom out full If you open a file with a graph you can edit the graph by using the right button on your mouse to right click on the graph Then you can change plot parameters and show underlying data If you click on the x or y axis you can for example change the scale This is the same re gardless of file type If you want to make a copy of the graph choose Edit and copy The se lection will be put on the clipboard If you want to c
86. situations it is needed to synchronize the execution of the programming sequence with the actions in the controller This is used by adding the OPC at the end of the com mand sequence This command will output a 1 to the controller when all pending commands have been executed 3 If a query was output to the frequency stan dard input its response 4 The sequence of points 2 and 3 may be re peated for different commands or queries 5 Close the communication channel W Order of Execution commands in frequency standards are se quential i e they are executed in the same or der as they are received Commands separated by semicolons on a single line are executed one by one without interrupting each other 8 12 Appendix 3 Command Reference Appendix Fluke 910 and 910R remote control command reference guide Fetch data FETCh Purpose The fetch query retrieves one measuring result from the measurement result buffer of the frequency standard If no parameter is entered then the last TIE value is fetched TIE Time Inter val Error or SIGNal received satellite signal strength measurement results can be selected Query Syntax FETCh SCALar lt nl gt FETCh SCALar TIE SIGNal lt nI gt Response Syntax numerical value gt lt nl gt Example SEND gt FETC lt nl gt READ lt 2 345600000000E 008 lt nI gt Fetch data array overview TRACe Purpose The TRACe query retrieves a stor
87. source command selects period and pulse width of the programmable pulse output Note The resolution of period and pulse width is 100ns Pulse width min 100 ns max 2 1 100 ns Period min 200 ns max 229 100 ns The value setting is stored in non volatile memory Command Syntax SOURce PULSe PERiod WIDTh numeric data gt lt nl gt Example SEND gt SOUR PULSe PER 1E 6 SOUR PULS WIDT 5 7 lt 1 gt This example turns on a 1 MHz square wave pulse signal on the output Query Syntax SOURce PULSe PERiod WIDTh lt nl gt Response Syntax numerical value gt lt nl gt Example SEND gt SOUR PULS PER nl READ 0 0000040 lt nI gt In this example the instrument is set up for 250 kHz pulse frequency period 4 us Output signal enabled OUTP Purpose The output command shows if the pulse output option option 75 is installed or not Note Select signal frequency and duty cycle with SOURce command Query Syntax OUTPut STATe lt nl gt Response Syntax lt 1 0 gt lt nI gt Example SEND gt OUTP lt nl gt READ 1 lt nl gt In this example the output is available option 75 is installed 8 17 Appendix 3 Command Reference Appendix Read status STAT OPER Purpose Read status operation event register Reading the Operation Event Register clears the reg Ister Query Syntax STATus OPERation EVENt lt nl gt Returned Format Decimal data gt lt nl gt lt dec data
88. status indicate that the antenna is disconnected 8 19 Appendix 3 Command Reference Appendix m SYSTem subsystem Interface settings Purpose Error code and explanation of bus commands Query Syntax SYSTem ERRor lt nl gt Example SEND gt SYST ERR lt gt Returned format numerical value gt lt string gt lt nl gt Example SEND gt SYSTem ERR lt nl gt READ lt 0 No error lt nl gt SSYST ERR Lock keyboard SYST KLOC Purpose Locks the keyboard to prevent user intervention when the frequency standard is under pro gram control Locked state is indicated by REMOTE on the display Command Syntax SYSTem KLOCKk lt Boolean gt lt nl gt Parameters Boolean Both ON OFF and 1 0 can be used lt nl gt Example SEND gt SYST KLOC ON lt nl gt Locks lt gt SEND gt SYST KLOC OFF lt nl gt Unlocks keyboard lt nl gt Query Syntax SYSTem KLOCk lt nl gt Response format 1 0 lt nl gt where 1 is locked and 0 is unlocked Example SEND gt SYST KLOC nl READ lt 0 lt 1 gt In this example the keyboard is unlocked 8 20 Appendix 3 Command Reference Appendix m TEST subsystem Select self test ITEST SEL Purpose Selects which internal self tests to run when the TST command is received Command Syntax TEST SELect RAMIROM NON Volatile JGPS ALL nl Note The default is ALL Example SEND gt TEST SEL ROM nl Sele
89. t WARNING Never interrupt the grounding cord Any interruption of the protective ground connec tion inside or outside the instrument or disconnection of the protective ground terminal is likely to make the instrument dan gerous Orientation and Cooling The frequency standard can be operated in any position desired Make sure that the air flow through the ventilation slots are not ob structed Leave 1 centimeter inches of space around the 910 910R CAUTION Never cover the ventila tion slots at the right or left side If the slots are covered the fre quency standard will overheat 2 5 Supply Voltage a wp Preparation for Use The 910 910R Fan Control Rackmount The fan is used to adjust the temperature inside the frequency standard to compensate for varia Ad a pte r tions in ambient temperature Figure 2 4 Dimensions for Figure 2 1 Air flow through the 910 910R rackmounting hardware If you have ordered a 19 inch rack mount kit Fo d d own S u p po rt for your instrument it has to be assembled af For bench top use a fold down support is avail nd delivery PPS mount kit consists of the following able for use underneath the frequency standard 2 brackets short left long right This support can also be used as a handle to carry the instrument PONO MIRS 4 screws M6 x 8 WARNING When you remove the cover you
90. t 1 4608969 06 3 474589985391 05 lt gt In this example the TIE value is 1 46 us and 347459 seconds approx 4 days have elapsed since first TIE measurement Command syntax SYSTem TALKonly ON OFF lt nl gt Query syntax SYSTem TALKonly lt nl gt Response format 0 1 lt nl gt 8 41 Appendix 3 Command Reference Appendix m Quick Alphabetical Overview of Commands CLS Clear status command DISP TEXT FEED Display feed DISP TEXT FEED SAVE Save display feed DISP TEXT FEED RES Restore display feed ESE Standard event status enable ESR Read event status register FETCh Retrieves one measuring result from the mea surement result buffer ofthe frequency standard GPS POS Installed antenna position GPS POS HOLD STAT Position hold query GPS POS SURV STAT Surveying satellites for position GPS REF ADEL Setting antenna delay time GPS REF VAL GPS REF STAT 1 signal status GPS STAT SYST STAT Satellite status GPS SAT TRAC Satellite tracking data GPS SAT TRAC COUNT Satellite tracking data GPS SAT TRAC EMAN Satellite tracking elevation mask GPS SAT VIS PRED Predicted visible satellite IDs GPS SAT VIS PRED COUN Predicted visible satellite count GPS SAT VIS PRED POS Predicted visible satellite data GPS VERS Get GPS receiver firmware version amp revision IDN Identification query OPC Synchroni
91. t satellites at the same time but in practice three is enough for timing pur poses when the receiver is stationary It is not certain that an elevated location is an advantage unless it is the only way to see as much of the sky as possible including the hori zon in most directions On the contrary loca tion on the ground could be more efficient from a technical point of view if you do not have to consider certain negative factors like the risk of physical damage and the influence of snow and ice on the antenna efficiency Other conditions to be taken into account are multi path reception and interference from high frequency signal sources nearby All these considerations could force you to find a place for the antenna situated far from the receiver and high above ground level We will discuss these matters presently but the implication in brief is that new system components may have to be in troduced like low loss coaxial cables and line amplifiers Appendix Coping with Interference There are mainly two sources of interference that may affect the location of the antenna They will be treated below Careful inspection of the proposed site can often reveal the most apparent ones m Multi path Reception Reflections from metal surfaces nearby can cause the wanted signal to enter the antenna from two or more directions with more or less equal strength Then the phase relationship de termines whether the resulting signal
92. tion or a pair of pliers to remove the springs holding each foot then push out the feet Vs ES a n Figure 2 5 Removing feet from the cover Remove the two plastic labels that cover the screw holes on the right and left side of the front panel 2 7 Rackmount Adapter a a Preparation for Use Antenna Installation The antenna option 01 is intended for outdoor mounting on a wall or preferably on a roof The more free sky that is visible from the antennas position the better the satellite contact The antenna cable is a 20 meter option 02 or 50 m option 02 50 high quality RG213 cable that connects in one end to the antenna and in the other end to the rear panel ofthe frequency stan dard For installation details and instructions on connecting other antennas cables than those supplied by Fluke please consult Appendix 2 in this manual Connecting to a PC A PC is connected to the RS232 port at the rear ofthe instrument A cable for connecting to a PC should have female DB9 connectors in both ends and be designed as a null modem cable 61 16 95 59 Figure 2 7 Connecting to a PC 2 8 Antenna Installation Optional Ethernet Connection Option 76 After configuration by means of the GPSView SW over the standard RS232 interface Option 76 lets the operator communicate with the GPS frequency standard in much the same way as with any Ethernet node Remote con trol and data loggi
93. tional Description The 910 and 910R are GPS controlled fre quency standards that are continuously cali brated to the GPS signal of one or several satel lites The GPS signal has a very low long term uncertainty of seq per 24h and is traceable to US Naval Office USNO and ultimately to NIST and other national standards for time and frequency The 910 9108 contain a GPS receiver module generating a stable 1 pps signal plus a voltage controlled local oscillator and a high resolution measurement kernel that is continuously phase comparing the received GPS signal and the local oscillator This means that the local oscillator is continuously cali brated The result of this comparison i e cali bration is stored in the unit once every 30 s From the collection of phase calibration data a frequency offset is calculated and displayed as a 24h mean frequency offset Also the 24h fre quency calibration data is stored internally once per 24h in non volatile memory The 910 910R can operate in two different modes Either the local oscillator is free running with a frequency offset that in creases with time due to aging Or the calibra tion result is used to adjust the local oscillator thereby compensating for aging These two modes are called Hold Over mode free running local oscil lator Disciplined mode controlled and adjusted local oscillators In both modes the local oscillator is always calibrated as long as
94. tory chain day by day is maintained in the non volatile memory for several years Furthermore the cur rent 24h mean offset is continuously displayed on the front panel Optional Outputs Phase m Local comparator osdillator VCO ef ererence Out 10 MHz The 910 high stability oven and 910R rubidium atomic clock come as standard with one 5 MHz and five 10 MHz sinewave outputs Also as standard there is a 1 pps one pulse per second output There are four options Figure 1 1 1 2 A typical black box GPS receiver to choose from options 70 71 72 and option 75 Options 70 71 and 72 al Preface low for five extra frequency outputs to be mounted and are mutually exclusive Option 70 gives 5 extra 10 MHz outputs Option 71 gives four 1 Vrms sine wave outputs of resp 10 MHz 5 MHz 1 MHz and 0 1 MHz plus a 0 1 MHz square wave output Option 72 gives five extra 2 048MHz outputs for telecommunication testing and clock syn chronization G 703 10 Option 75 allows the user to define his own pulse frequency output as long as the pulse pe riod is an integer multiple of 100 ns Two Operating Modes To fully eliminate long term frequency changes aging you should have an automatic adjust ment known as disciplining This disciplined mode is the default mode in the 910 910R As long as there is a valid satellite signal the inter nal local oscillator is monitored
95. um found underflow 1212 Wrong hash table checksum found Device operation gave floating point 1213 RAM failure to hold info hash table overflow 1214 Hash table overflow Device operation gave notanumber 1220 Parser error Invalid measurement function 1221 Illegal parser call Save recall memory protected 1222 Unrecognized input character Unsupported command 1223 Internal parser error Unsupported boolean command 1230 Response formatter error Unsupported decimal command 1231 Badresponse formatter call Unsupported enumerated command 1232 response formatter call eom Unsupported auto command 1233 Invalid function code to response for Unsupported single shot command matter Command queue full last command 1234 Invalid header type to response format discarded ter Inappropriate suffix unit 1235 Invalid data type to response formatter Unexpected command to device exe 1240 Unrecognized error number in error cution queue Unexpected query to device execu 1300 Calibration error reading upper limit tion 1301 Calibration error reading lower limit Bad math expression format 1302 Calibration reading difference Measurement broken off 1303 Max Min Instrument set to default Calibration error reading at Max Bad setup data length 1304 Calibration error reading at Min Bad setup data checksum 1305 Calibration base level error Error during calibration 1306 Calibration scale factor error Message exchange error 1307 Calibration hysteresis error
96. w the instruc Update database update the current data tions on screen After selecting the serial port to base archive use GPSView will connect to the instrument Print graph print the active document and retrieve the current network parameter set Print preview display the active graph in tings If you get the error message Wrong re sponse from instrument verify the following Print setup and try again print preview mode change the printer and printing options Set user informa enter user name company tion name and other relevant user info free field text entry for use in the cali bration protocol On the next screen you will enter the network Print calibration print a traceable calibra parameters These values are dependant on the protocol tion protocol referring the configuration of the network where the instru reference to GPS ment will be connected Please contact your Exit quit the application network administrator if in doubt Entering in correct values may cause instrument malfunc Correct Communication Port selected Serial cable and connectors secureley hooked up Rear panel switch set to Ethernet tion or conflicts with other equipment con ipis nected to the same network Save Css Save As When the configuration is completed flip the Select Database Sn ase Database switch on the rear panel to the Serial posistion and back to Ethernet dis
97. will expose live parts and accessible terminals which Figure 2 2 Fold down support for comfort can cause death able bench top use WARNING Capacitors inside the in strument can hold their charge even if the instrument has been separated from all voltage sources Figure 2 3 Use the support to carry the frequency standard 2 6 Fold down Support 4b i a a Preparation for Use Assembling the Rackmount Push the frequency standard back in the Kit cover ie Sa Turn it upside down Make sure the power cord is disconnected swell from the frequency standard Install the two rear feet with the screws Turn the frequency standard upside down B to the rear panel Fasten the brackets at the left and right side with the screws included Fasten the front panel and mounting plate m Reversing the Rackmount Kit The frequency standard may also be mounted Figure 2 6 Remove the screws and to the right in the rack To do so first remove push out the frequency the plate on the long bracket and fasten it on standard from the cover the short one then perform the preceding steps Loosen the two screws B in the rear feet Grip the front panel and gently push at the rear Pull the frequency standard out of the cover Remove the four feet from the cover Use a screwdriver as shown in the illustra
98. y particular purpose or use We shall not be liable for any direct indirect special incidental or conse quential damages whether based on contract tort or otherwise IV DECLARATION OF CONFORMITY for Fluke GPS Controlled Frequency Standard 910 910R Fluke Precision Measurement Ltd Norwich Airport Industrial Estate Norwich Norfolk NR6 6JB UK Statement of Conformity Based on test results using appropriate standards the product is in conformity with Electromagnetic Compatibility Directive 89 336 EEC Low Voltage Directive 73 23 EEC Sample tests Standards used EN 61010 1 1990 A1 1992 A2 1995 CAT II Safety Requirements for Electronic Measuring Apparatus EN 61326 1 1997 Electrical equipment for measurement control and laboratory use EMC requirements The tests have been performed in a typical configuration This Conformity is indicated by the symbol Le Conformit europ enne This page is intentionally left blank VI Chapter 1 Preface i Preface Introduction Cesium controlled Frequency via GPS Satellites The GPS controlled frequency standards 910 and 910R deliver a precision frequency and time reference everywhere in the world They receive their long term frequency stability from built in Cesium standards in the GPS satellites The 910 910R are designed to provide a very high short term stability They are cost efficient traceable and extremely accurate
99. y contain the characters you should send to the frequency standard and the re sponses that you should read with the control ler Example SEND gt FETCH SEND gt means that you should write your program so that it will output this string to the serial port READ lt 1 234567890E 6 READ lt means that you should write your pro gram so that it will input this string from the se rial port m SCPI Programming Language SCPI Standard Commands for Programmable Instruments is a standardized set of commands used to remotely control programmable test and measurement instruments Reason for SCPI For each instrument function SCPI defines a specific command set The advantage of SCPI is that programming an instrument is only func tion dependent and no longer instrument de pendent Several different types of instruments for example an oscilloscope a counter and a multimeter can carry out the same function such as frequency measurement If these instru ments are SCPI compatible you can use the same commands to measure the frequency on all three instruments although there may be dif ferences in accuracy resolution speed etc The Frequency Standard firmware is compliant with the SCPI It defines the syntax and seman tics that the controller must use to communicate Appendix with the instrument This chapter is a short overview of SCPI and shows how SCPI is used in Frequency Standards SCPI is based on IEEE 488 2
100. zes instrument operations and con troller OPT Option query OUTP Shows if the pulse output option is installed or not PTIM LEAP ACC Leap second difference between UTC and GPS time PTIM LEAP DUR Leap minute duration PTIM LEAP STAT Leap second pending PUD Protected User Data setting and query RST Reset SOUR PULSe Selects period and pulse width of the program mable pulse output 8 42 Appendix 3 Command Reference Appendix SRE SYST TIME Service request enable query Get time STB TZON PTIM TZON Status byte query Set timezone STAT OPER SYST VERS Read status operation event register SCPI version query STAT OPER COND SYST TALK Read status operation condition register Talk only mode SYNC FFOM TEST SEL Frequency output signal quality Selects which internal self tests to run when the TST command is received SYNC HOLD DUR Hold over duration TRACe Retrives a stored array of TIE measurements SYNC HOLD INIT CAL AUTO OFF Selecting manual Hold over mode TRACe ARC24H Fetch data array 24h frequency offset SYNC HOLD REC INIT CAL AUTO ON non volatile archive Selecting GPS disciplined mode TRACe DEVIH TRACe DEV24H SYNC STAT Fetch data array 1 or 24h frequency offset Operational mode RAM SYST ALAR ENAB NOAN JRACSTIE No antenna alarm enable Fetch data array TIE SYST DATE PTIM DATE TST G

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