UAPP223 Reading time form the GTX Satellite Transmitter into the
Contents
1. In seconds In seconds In seconds In seconds GTX Maximum 0 02166 0 1516 0 65 Transmitter Drift CR1000 Logger Maximum Drift Max Logger to 0 52166 3 6016 15 45 Transmitter Clock Differential The logger is usually set manually initially Setting the time manually will most likely have an initial update time inaccuracy which we will call Logger Update Time 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 2 Application Note Microcom GTX Modulator Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger UAPP223 v1 0 July 12 2005 Author Richard Schwarz PRELIMINARY Inaccuracy LUTI which represent the difference between the logger time set and the actual UTC time The Maximum Logger to Tx Clock Differential MLTCD for our system in a given time period can be estimated given the following formula MLTCD MaxLoggerDrift MaxGTXDrift The MLTCD inaccuracy for a given time period would be MLTCDI LUTI MLTCD Lastly we can define a third value called the Maximum System to UTC time Inaccuracy MSUI which is simply MSUI MLTCDI TUTI This would represent the maximum timing inaccuracy from UTC time that the Logger sees It DOES NOT represent the GTX transmission time error which is determined only by the transmitter clock drif2. 1 Then SerialOut Com1 Mess1 0 100 SerialOut Com1 Date 0 100 SerialOut Com1 CRLF 0 100 SerialOut Com1 Mess2 0 100 SerialOut Com 1 InString 0 100 SerialOut Com1 Mess2 0 100 SerialOut Com1 InString 0 100 SerialOut Com1 CRLF 0 100 SerialOut Com1 LINE 0 100 SerialOut Com1 CRLF 0 100 Endlf Break up Date String SplitStr ValStr 1 InString 1 0 SplitStr ValStr 2 InString 2 4 Assign Month Month ValStr 1 If DebugOnOff 1 Then SerialOut Com1 Month gt 0 100 SerialOut Com1 ValStr 1 0 100 SerialOut Comil 0 100 Endlf Assign Day Day ValStr 2 If DebugOnOff 1 Then SerialOut Com1 Day gt 0 100 SerialOut Com1 ValStr 2 0 100 SerialOut Com1 0 100 Endlf Assign Year Year ValStr 3 If DebugOnOff 1 Then SerialOut Com1 Year gt 0 100 SerialOut Com1 ValStr 3 0 100 SerialOut Com1 CRLF 0 100 Endlf 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 9 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger EndSub In our GetGTIxTime routine It is assumed that the GTX time is already set If it isn t the GTX will respond with the message Not Set A conditional statement can be implemented to handle this
3. 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 15 com Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger SerialOut Com1 Mess2 0 100 SerialOut Com1 nString 0 100 Endlf Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess2 0 100 SerialOut Com1 nString 0 100 SerialOut Com1 CRLF 0 100 SerialOut Com1 LINE 0 100 SerialOut Com1 CRLF 0 100 Endlf Breakup Time String SplitStr ValStr 1 InString 1 0 SplitStr ValStr 2 InString 2 4 SplitStr ValStr 4 ValStr 3 1 4 SplitStr ValStr 3 ValStr 3 1 5 Assign Hours Hours ValStr 1 If DebugOnOff 1 Then SerialOut Com1 Hours gt 0 100 SerialOut Com1 ValStr 1 0 100 SerialOut Com1 0 100 Endlf Assign Mins Mins ValStr 2 If DebugOnOff 1 Then SerialOut Com1 Mins gt 0 100 SerialOut Com1 ValStr 2 0 100 SerialOut Com1 _ 0 100 Endlf Assign Seconds Secs ValStr 3 If DebugOnOff 1 Then SerialOut Com1 Secs gt 0 100 SerialOut Com1 ValStr 3 0 100 SerialOut Com1 0 100 Endlf Assign Microsecs uSecs ValStr 4 If DebugOnOff 1
4. Com1 Year gt 0 100 SerialOut Com1 ValStr 3 0 100 SerialOut Com1 CRLF 0 100 Endlf EndSub UCOCUOCU UCU EEUU UEC eee PE Main Program UCOUUOUC UCU WANKAN ANANE AAAA EEEE BeginProg CALL Initialize Infinite loop to be executed every ten seconds Scan 10 Sec 0 0 take panel temp Panellemp PTemp 250 take internal cr1000 baterry voltage Battery batt_volt Call Temperature Table CallTable TempTbl Send CRs until getting Com4 gt gt SerialOut Com4 CR gt 100 100 Send Baterry Voltage to the Com4 in a Random Data Command 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 17 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger SerialOut Com4 RandomData 0 100 SerialOut Com4 batt_volt 0 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess1 0 0 SerialOut Com1 RandomData 0 100 SerialOut Com4 CRLF 0 100 SerialOut Com1 batt_volt 0 100 SerialOut Com1 CRLF 0 100 Endlf Get responce from GTX Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess2 0 0 SerialOut Com1 nString 0 100 Endlf Get responce from GTX Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If De
5. be off id uncorrected In this case to correct this we probably would be safe updating the logger time from the more accurate GTX time every few weeks If the logger update time inaccuracy was greater than 2 minutes of course the problem gets worse or can show up right away By syncing the Logger time to the more accurate GTX time the entire system operation becomes more accurate In fact if we recently updated the logger clock from the GTX clock and we lost power time on the GTX clock we could actually update he GTX clock from the Logger clock if done so within 4 5 hours of the last logger GTX update This could also be done if the logger was attached directly to t own source of a more accurate time GPS Time Standard etc For random GOES transmissions where transmissions are not tied to timeslots the timing is not as critical 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 5 Application Note Microcom GIX Modulator UAPP223 v1 0 July 12 2005 Author Richard Schwarz PRELIMINARY Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger OK so we have decided to update the logger clock with the more accurate GTX clock We are feeling very good about our system now We have to be careful however not to introduce even more problems Lets examine
6. insure that the maximum drift allowed by your resync update rate does not allow these packet send times to be missed 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 http www microcomdesign com 7 UAPP222 v1 0 July 12 2005 com Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger GetGTXTime Subroutine Code The text of a subroutine is shown below which can get the time from the GTX transmitter and set the current time of the CR1000 Variables should be declared at the top of the CrBasic file and the COM ports being used also need to be opened before calling this routine Also a DebugOnOff variable is also used which if set to a 1 will output debug messages to a com port which can be viewed on a standard terminal Sub GetGIXxTime Request Time from GTX SerialOut Com4 Time 0 100 SerialOut Com4 CRLF 0 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess1 0 100 SerialOut Com1 Time 0 100 SerialOut Com1 CRLF 0 100 Endlf Get GTX Responce Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess2 0 100 SerialOut Com1 nString 0 100 Endlf Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess2 0 100 SerialOut Com1 nString 0 100 S
7. our last example and lets go ahead and resync our clocks after sending our last packet to the GTX since we are talking to the GTX at that time anyway resync clocks here TX Transmit Time G Last Logger Packet sent tOGTX NW First Logger Packet sent to GTX Ok this looks good at first glance but lets remember that our clock has drifted and we are adjusting it Further lets say we do the correction at a fairly slow update rate such that some amount of drift is allowed A more accurate picture would be this one with some drift introduced resync clocks here Now lets look at what the picture looks like after we readjust the clock As can be 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 6 Application Note Microcom GTX Modulator Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger UAPP223 v1 0 July 12 2005 Author Richard Schwarz seen the readjusted time places us in a position where we actually resend our last packet again After resyncing the logger time places us here NV Transmit Time tJ se o d The same situation could occur if we resync before sending the packet and the drift was in the opposite direction The best solution in this instance is to split the difference and resync the clock between Logger packet sends and
8. Application Note Microcom GTX Modulator UAPP223 v1 0 July 12 2005 Author Richard Schwarz PRELIMINARY Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger SUMMARY INTRODUCTION The Microcom Model GTX Satellite Transmitter and Data Collector works on GOES GMS ARGOS SCD amp METEOSAT systems The GTX has some data logger functions built into it including an SDI 12 and counter input The GTX can interface to external data acquisition systems like the Campbell Scientific Programmable Data Logger via its RS 232 port Microcom GTX Satellite Transmitter Campbell Scientific Programmable Data Logger The GTX internal time keeping is 0 25 PPM 0 65 seconds per month or 0 02 seconds per day maximum With GPS this is improved to 0 1 milliseconds at the GPS update time and drifts at the max rate of _0 25 PPM until the next GPS update This is more accurate than the CR1000 s internal clock and so it makes sense to set the CR1000 clock to the GTX clock s more accurate time This Application note goes shows how to read the time in the GTX Transmitter and then set the internal time of the CR1000 to the potentially more accurate time of the GIX Some potential problems will be discussed with strategies developed to insure the best system operation A subroutine is introduced which can be used in CRBASIC programs to bring in the system time from the GTX Transm
9. Then SerialOut Com1 millisecs gt 0 100 SerialOut Com1 ValStr 4 0 100 SerialOut Com1 CRLF 0 100 Endlf Request Date from Com4 SerialOut Com4 Date 0 100 SerialOut Com4 CRLF 0 100 Serialln InString Com4 100 10 100 Serialln InString Com4 100 10 100 If DebugOnOff 1 Then SerialOut Com1 Mess1 0 100 SerialOut Com1 Date 0 100 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 16 com Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger SerialOut Com1 CRLF 0 100 SerialOut Com1 Mess2 0 100 SerialOut Com1 InString 0 100 SerialOut Com1 Mess2 0 100 SerialOut Com1 InString 0 100 SerialOut Coml CRLF 0 100 SerialOut Com1 LINE 0 100 SerialOut Com1 CRLF 0 100 Endlf Break up Date String SplitStr ValStr 1 InString 1 0 SplitStr ValStr 2 lnString 2 4 Assign Month Month ValsStr 1 If DebugOnOff 1 Then SerialOut Com1 Month gt 0 100 SerialOut Com1 ValStr 1 0 100 SerialOut Com1 _ 0 100 Endlf Assign Day Day ValStr 2 If DebugOnOff 1 Then SerialOut Com1 Day gt 0 100 SerialOut Com1 ValStr 2 0 100 SerialOut Com1 _ 0 100 Endlf Assign Year Year ValStr 3 If DebugOnOff 1 Then SerialOut
10. assign the alias Hour to rTime 4 PulsePort Alias myTime S Mins assign the alias Minute to rTime 5 Rainflow Alias myTime 6 Secs assign the alias Second to rTime 6 hal Randomize E fReado g ersion C Campbellsci Lib Compilers CR1Comp exe YERSION CR1000 Std 02 DATE 041217 C CAMPBELLSCI CRBASICEDITOR MICROCOMTEST CR1 Compiled in PipelineMode 174 lines written to C CAMPBELLSCI CRBASICEDITOR MICROCOMTEST CR1 The code for our program is shown below called MICROCOMDATA CR1 Program GTXRand cr1 Description GTX Random Data Transmission Program CR1000 Series Datalogger forwa RandomData Battery Voltage and Temperature to the GTX in Random Mode Time and Date is read from the GTX using Subroutine GetGITXTime program author R Schwarz Microcom Design Incorporated program date Original Code May 1 2005 Declare Public Variables Public Plemp Public CR as string 1 Public LF as string 1 Public CRLF as string 2 Public PROMPT as string 1 Public myTime 7 Public Dest 9 Public InString as string 100 Public ValStr 4 as string 100 Public LINE as string 100 Public Mess as string 100 Public Mess2 as string 100 Public Batt_volt 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 14 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter in
11. bugOnOff 1 Then SerialOut Com1 CRLF 0 100 SerialOut Com1 Mess2 0 100 SerialOut Com1 nString 0 100 Endlf Send CRs until getting Com4 gt gt SerialOut Com4 CR gt 100 100 Send Temperature to the Com4 in a Random Data Command SerialOut Com4 RandomData 0 100 SerialOut Com4 Temp PTemp 0 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess1 0 0 SerialOut Com1 RandomData 0 100 SerialOut Com4 CRLF 0 100 SerialOut Com1 Temp PTemp 0 100 SerialOut Com1 CRLF 0 100 Endlf Get responce from GTX Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess2 0 0 SerialOut Com1 nString 0 100 Endlf Get responce from GTX Serialln InString Com4 100 10 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 CRLF 0 100 SerialOut Com1 Mess2 0 100 SerialOut Com1 InString 0 100 Endlf Get Time from GTX Call GetGTXTime Set CR1000 Station CLock to the new values ClockSet myTime NextScan EndProg 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 18 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger Once the program is written we need to download it to the CR1000 and all
12. case when the GTX time is read We can develop a subroutine which first checks the GTX time The following routine does this I y bro y in giii Sub CheckGtxTime Send CRs until getting Com4 gt gt SerialOut Com4 CR gt 100 100 Request Time from GTX SerialOut Com4 Time 2 0 100 SerialOut Com4 CRLF 0 100 Echo stuff to Debug Terminal If Debug 1 Then SerialOut Com1 Mess1 0 100 SerialOut Com1 Time2 0 100 SerialOut Com1 CRLF 0 100 Endif Get GTX Responce Serialln InString Com4 100 10 100 If INString Not Set then GtxTimeSet 0 Else GixTimeSet 1 endif endsub Then you could insure that the GetGtxTime isn t called unless the GtxTime is set CheckGixTime check GTX time to see if it is set If GtxTimeSet then GetGTxTime if itis then set to GTX time 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 10 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 11 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger Sample Application File In this next test
13. erialOut Com1 CRLF 0 100 SerialOut Com1 LINE 0 100 SerialOut Com1 CRLF 0 100 Endlf Breakup Time String SplitStr ValStr 1 InString 1 0 SplitStr ValStr 2 InString 2 4 SplitStr ValStr 4 ValStr 3 1 4 SplitStr ValStr 3 ValStr 3 1 5 Assign Hours Hours ValStr 1 If DebugOnOff 1 Then SerialOut Com1 Hours gt 0 100 SerialOut Com1 ValStr 1 0 100 SerialOut Comil 0 100 Endlf Assign Mins Mins ValStr 2 If DebugOnOff 1 Then SerialOut Com1 Mins gt 0 100 SerialOut Com1 ValStr 2 0 100 SerialOut Com1 0 100 Endlf Assign Seconds Secs ValStr 3 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 8 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger If DebugOnOff 1 Then SerialOut Com1 Secs gt 0 100 SerialOut Com1 ValStr 3 0 100 SerialOut Com1 0 100 Endlf Assign Microsecs uSecs ValStr 4 If DebugOnOff 1 Then SerialOut Com1 millisecs gt 0 100 SerialOut Com1 ValStr 4 0 100 SerialOut Com1 CRLF 0 100 Endlf Request Date from Com4 SerialOut Com4 Date 2 0 100 SerialOut Com4 CRLF 0 100 Serialln InString Com4 100 10 100 Serialln InString Com4 100 10 100 If DebugOnOff
14. ime from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger PRELIMINARY ZjMicrocom GTX Utility ersion 2 00 File Options Advanced About Configuration Options General Setup Transmission Setup SDI 12 Sensors Internal Sensors Timed Data Buffer Random Data Buffer Configure GTX From Template Monitor Z Inspect GTX Configure Control 7 Deploy GTX What Do You Want To Do gt Retrieve Config From GTX Create Open A Setup Template M Platform ID 77880016 Next SDI 12 Sensor Sample Next Internal Sensor Sample Timed Data Buffer Random Data Buffer GTX Information Last Transmission GPS Status Currant Date isre ssa 01702 2005 Current Time 03 04 24 Firmware Version M1 10 T1 4 Serial Number sony E Transmitter State Enabled Time To Next Transmission 00 00 07 50 Timed Buffer Size 0 Next Timed Transmission Not Available Random Buffrer Size 1148 Random Buffer Transmissions 3 Next Random Transmission 01 02 2005 03 12 15 Fail Safe Status ton LS GPS Calibration Status Not Active BA coma svn 1138 Once alll this is done we use the LOGGERNET software s CRBASIC editor to actually write the program Once again the LOGGERNET Software s capabilities are beyond the scope of this application note and it is as
15. itter The basic setup and connections for the CR1000 and GTX is referenced in the Microcom Application Note UAPP222 User s of this application note should be familiar with or have access to basic coding techniques user s manuals and software associated with using the GTX and CR1000 including 1 Microcom GTX User s Manual 2 Microcom GTX GUI Software 3 Campbel Scientific CR1000 User s Manual 4 Campbell Scientific LoggerNet Software The timing on systems operating on platforms like the GOES DCP is critical Because of the use of timed transmissions with time slot assignments in these systems the transmission clock can be are required to be accurate to within 0 1 seconds of the actual UTC time This requirement falls on the transmitters like the GTX which get certified by NOAA NESDIS This requirement is often satisfied with the use of a GPS 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 1 Application Note Microcom GIX Modulator Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger UAPP223 v1 0 July 12 2005 Author Richard Schwarz PRELIMINARY receiver The GTX transmitter which is a certified GOES transmitter handles most of the timing requirements automatically once it is set up for GOES operation For example until the GTX clock
16. ock via it s GPS capability than the Campbell CR1000 Data logger A subroutine was developed which can be used in CRBASIC for the CR1000 to get the GTX time and set the CR1000 to the more accurate time Revision Date Version Revision History July 12 2005 1 0 Initial Microcom Preliminary Release September 20 2005 1 01 Added a more detailed timing analysis example 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 21
17. ow the CR1000 to compile the program For this we select the CONNECT button on the Logger Net software ioixi File Tools Options Help aleje 82 Bais EZSetup Setup Connect Status Edlog Short Cut CRBasic a8 Connect Screen CR1000 CR1000 5 iol x File Edit Tools Data Help Stations Data Collection Clocks Collect Now Custom Server Date Time 5 5 2005 1 05 18 PM E Station Date Time Program 6 12 2041 1 04 02 AM Check Clocks Set Station s Clock Data Displays JV Pause Clock Update Graphs a a A List Alphabetically Memes E E a Elapsed Time Bus Di 0 02 15 25 connect J Pause Ports and Flags Pe es As can be seen on the connect screen we will also be able to read the CR1000 clock from this screen to verify the time change our program will make MICROCOMTEST CR1 Receive We can hook a standard terminal to the COM1 port of the CR1000 and view our debug echo outputs as the program runs 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 htto www microcomdesign com 19 Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger _ RealTerm Serial Capture Program 1 99 0 34 j i 5 x Display Port Capture Pins Send EchoPort 120 Misc n Clear Freeze Frage A
18. program we will format the data sent by the CR1000 to enable the GTX to include the data messages in its buffer for a random transmission The GTX s serial port responds to commands and data We will send a Random Data message from the CR1000 to the GIX In our case we will use the CR1000 Battery Voltage We will also read the GIX s Time and Date and set the CR1000 local clock to the GTX time NOTE Check vapp222 for CR1000 to GTX interfacing Instructions First we must set up the GIX Using the Microcom GIX Utility software we can set the GIX up for Random transmission The Microcom GIX utility runs on a PC and needs for a PC serial port to connect up to the GTX serial port We do this for now by disconnecting the PC connection from the CR1000 instead so that the PC is now connected to the GIX serial port Once the GIX is set up and enabled then the GIX serial connection should be attached to the CR1000 COM4 The full use of the GTX utility is beyond the scope of this application note and is not going to be covered in this application note The GTX needs to be set to accept Random Data Tx and it needs to be enabled A configuration file was saved called ricktestConfigFile txt which does this After opening up the file you also need to ENABLE the GTX 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 12 pcom Reading t
19. s Half Duplex Binary Syne Chars Status esce LF is New Line ABCD 7 V chanad Disconnect A a J Invert Data 1 Change I RxD 2 C Hex Asci A Eni z xor _ITXD 3 s uint8 Data Frames M YS AND _ CTS 8 j ma Bytes 2 2 JE DCD 1 e Singe _ Gul None ASCII Number _ DSR 6 intB n i _ Ring 9 C uintl6 e C Ascii Font _ BREAK Hex Font Terminal Font TE Errar Char Count 78492 ICPS 0 No UART Overrun No Buffer Overflow No Other Errors Port 7 9600 8N1 None We can then go back and see our updated clock on the Connect Screen gt Connect Screen CR1000 CR1000 loj x Fie Edit Tools Data Help mStations Data Collection Clocks Collect Now Custom Server Date Time 575 2005 2 33 58 PM ee Station Date Time 9 1 2 2005 3 44 07 AM MICROCOMTEST CR1 Send Receive Data Displays 7 J Pause Clock Update Graphs 2 y List Alphabetically Numetic ee ca 3 pelea Time Bas Disconnect Pause Ports and Flags 0 02 45 1 6 Set Station s Clock Check the date time For the current station 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 20 Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger Conclusion The MICROCOM Model GTX Satellite Transmitter has access to a more accurate cl
20. sumed that the user is somewhat familiar with the software 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 13 pcom Reading time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger CRBasic Editor C CAMPBELLSCI CRBASICEDITOR MICROCOMTEST CR1 for the CR1000 Ele Edt Search Compile Template Instruction Options Window Help l x dlalSle Slal sea a TS CR1000 Series Datalogger To create a different opening program template type in new Insert instructions and select Template Save as Default Template date fies program author R Schwarz All Declare Public Variables ModBusSlave Example Modem angup EndModemHang Public batt_volt MovePrecise Public CR as string 1 Network Public LF as string 1 NOT Public CRLF as string 2 Openinterval Public PROMPT as string 1 pH eik Public MESSAGE as string 100 PanelT emp Public InString as string 100 PeakValley Public ValStr 4 as string 100 PeriodAvg Public myTime 7 er i Public Dest 9 PortsConfig PortSet Alias myTime l Year assign the alias Fear to rTime il PRT Alias myTime Z Month assign the alias Month to rTime 2 Eiio Alias myTime 3 Day assign the alias Day to rTime 3 PulseCountReset Alias myTime 4 Hours
21. t and the time of the last GPS update and is much lower One might ask how much of a problem is having an inaccurate drifting Logger clock reallly is since the GIX s transmission time requirement is met with a superior GIX clock Let s do an example In our example scenario we will assume we have a 2 minute Logger Update Time Inaccuracy This represents the difference between the time manually set in the logger and the time in the GTX clock which we will assume got a GPS lock and is essentially UTC time Well lets say that in our scenario we send data to the GIX from the logger every five minutes and we start the first logger send at 2 5 minutes after the top of the hour 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 3 Application Note Microcom GIX Modulator UAPP223 v1 0 July 12 2005 Author Richard Schwarz PRELIMINARY Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger GTX Transmit Time Last Logger Packet sent to GTX Arst Logger Packet sent to GTX X Also assume that we transmitted from the GTX at the top of the hour every 4 hours The added 2 5 minutes will insure that we are well away from the top of the hour when the GTX transmits when we send the first GTX packet from the Logger So each GTX transmission will contain 12 da
22. ta packets form the logger Lets subtract the logger update time inaccuracy from our offset of 2 5 minutes which only leaves us a timing margin of 30 seconds If the drift error is in the same direction as the offset error and lets say the logger clock is running faster than the GTX clock and that the offset error places the initial logger time at 2 minutes fast Logger Clock drift logger clock fast causes the actual packet send times to rotate relative to actual UTC time Then from the MLTCD values shown if the Logger times are allowed to drift the last message in the GTX packet will become the first value in the GTX packet ie the 2005 Microcom Design Inc All rights reserved voice 401 771 1070 Fax 410 771 0018 UAPP222 v1 0 July 12 2005 http www microcomdesign com 4 Application Note Microcom GTX Modulator TICOTT Reading Time from the MICROCOM DESIGN GTX Satellite Transmitter into the Campbell Scientific CR1000 Data Logger UAPP223 v1 0 July 12 2005 Author Richard Schwarz PRELIMINARY Logger clock drift error is greater than 30 seconds after 2 months Uncorected after two months the loggers last send packet slides over to become the loggers first send packet GTX Transmit va This can be a real problem if you are expecting the data to be in a certain positions in the GTX transmission Also if any time information is embedded in the logger send packets they will obviously
23. time is set the GTX will not transmit in GOES mode Table 1 shows the maximum drift of the GTX transmitter s internal clock With GPS this is improved to 0 1 milliseconds at the GPS update time We will call this parameter the Transmitter s Update Time Inaccuracy TUTI note that the GTX TUTI is 1000 times better than the specification requirement right after the update UNIT Drift per day Drift per week Drift per month Drift Per year In seconds In seconds In seconds In seconds Max Transmitter 0 02166 0 1516 0 65 Clock Drift MTCD With a GTX clock drift rate of 0 02166 seconds per day and a NESDIS specification for timed transmissions of being within 0 1 seconds of actual UTC the GIX could after an initial update run for up to four and a half days before needing another GPS update The GIX s Post updated Instantaneous time inaccuracy after a given time if not updated is given in table 2 and is simply the TUTI MTCD After 1 day After 1 week After 1 month After 1 year In seconds In seconds In seconds In seconds GIX s Post 0 02176 0 1517 0 6501 8 001 Updated Instantaneous Timing Inaccuracy TPUITI We already mentioned that the GTX clock is more accurate than the logger s clock The GTX s clock will always drift less then the logger s internal clock As shown in the following table UNIT Drift per day Drift per week Drift per month Drift Per year
24. to the Campbell Scientific CR1000 Data Logger Units Batt_Volt Volts Constant Declarations K Const DebugOnOff 1 PE PE Alias Declarations Alias myTime 1 Year assign the alias Year to rTime 1 Alias myTime 2 Month assign the alias Month to rTime 2 Alias myTime 3 Day assign the alias Day to rTime 3 Alias myTime 4 Hours assign the alias Hour to rTime 4 Alias myTime 5 Mins assign the alias Minute to rlime 5 Alias myTime 6 Secs assign the alias Second to rlime 6 Alias myTime 7 uSecs assign the alias uSecond to rTime 7 Define Data Tables N ImaiMiMMNMINIIHIMHIHINAN Test Data Table DataTable TempTbl 1 1 Datalnterval 0 10 Sec 10 Minimum 1 batt_volt FP2 0 False Sample 1 PTemp FP2 EndTable Define Subroutines ns Sub Initialize Use Com as an ECHO output port to viwe on Com SerialOpen Com1 9600 0 0 10000 Setup Com4 serial port to GTX SerialOpen Com4 9600 0 0 10000 CR CHR 13 LF CHR 10 CRLF CHR 13 CHR 10 PROMPT gt LINE Mess1 CR1000 TO Com4 gt Mess2 Com4 TO CR1000 gt EndSub K Get the Microcom GTX Time Sub GetGTXTime Request Time from GTX SerialOut Com4 Time 0 100 SerialOut Com4 CRLF 0 100 Echo stuff to Debug Terminal If DebugOnOff 1 Then SerialOut Com1 Mess1 0 100 SerialOut Com1 Time2 0 100 SerialOut Com1 CRLF 0 100 Endlf Get GTX Responce Serialln InString Com4
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