PCSAT2 TELEMETRY DEFINITIONS AND EQUATIONS 22 Aug 2005 -------------------------------------------------------------------------- rev1 12 Dec 2003 rev2 4 Mar 2005 rev3 28 Apr 2005 Swapped Isol and Iload and changed "10" fm Cell1 to Cell2 rev4 22 Aug 2005 swapped Load & Sol current in EQN table to be consistent and fixed the two Cell-1's to be 1 and 2 This is the validated as-wired telemtry channels for PCSAT2. The twenty channels of PCSAT2 telemetry are multiplexed into 4 sequential frames of telemetry. Every telemetry frame consists of 5 analog channels, 8 on/off status bits, two CONTROL bits, two FRAME counter bits and a final single status bit. It takes four such frames to constitute the complete telemetry picture of PCSAT2. The format of each frame is: PCSAT2>APRTLM,SGATE:T#SSS,111,222,333,444,555,11111111,XXYY,ZZ Where the header is PCSAT2>APRTLM,SGATE: (These fields may vary) Within the actual data portion of the packet are these fields: SSS is the serial number 111 is the first channel telemetry 222 is the second channel 333 is the thrid channel 444 is the forth channel 555 is the fifth channel 11111111 is the status of the 8 ON/OFF OUTPUT commmand bits XX is the status of the CTRL-A and CTRL-B outputs YY is the 1-of-4 telemetry FRAME counter (00,01,10,11) Z is a single telemtery ON/OFF bit. Notice, the YY bits tell you which frame you have. Here are the verififed channels for PCSAT2: YY CHANNEL 1 CHANNEL 2 CHANNEL 3 CHANNEL 4 CHANNEL 5 -- ----------- ----------- ----------- ------------ ------------ 00 RXA-current RXB-current BAT-CELL3 TNCA-current TNCB&RXC-Cur 01 BAT-Temp PEC-Temp TXA-current TXB-Current Bat-Cell1 10 TXA-Temp TXB-Temp Bat-Cell2 RX-Temp TLM-Temp 11 Bat-Volts Bat-Current Load-Current Sol-Current 5-Volts Telemetry equations are generally of the form y = aX^2 + bX + C where X is the 3 byte decimal telemetry count in each channel in the data. For PCSAT2, however, all channels are linear except for the temprature which are y=.00001X^3 - .0034X^2 + .7134X - 33.49 CHANNEL A B C UNITS Equation basis ------------- ----- ----- ------ ----- --------------------------- RXA-current 0 2 0 mA a count of 256 = 512 mA RXB-current 0 2 0 mA a count of 256 = 512 mA BAT-CELL3 0 0.0498 0 volts TNCA-current 0 2 0 mA a count of 256 = 512 mA TNCB&RXC-Cur 0 2 0 mA a count of 256 = 512 mA BAT-Temp . .. . degC See cubic equation above PEC-Temp . .. . degC See cubic equation above TXA-current 0 5 -5 mA a count of 256 = 1.33 Amps TXB-Current 0 5 0 mA a count of 256 = 1.33 Amps Bat-Cell1 0 0.0504 0 volts TXA-Temp . .. . degC See cubic equation above TXB-Temp . .. . degC See cubic equation above Bat-Cell2 0 0.0500 0 volts RX-Temp . .. . degC See cubic equation above TLM-Temp . .. . degC See cubic equation above Bat-Volts 0 0.1 0 volts Bat-Current 0 -22.44 +2842 mA a count of 128 is 0 Load-Current 0 15.43 20 mA a count of 128 is about 2000 mA Sol-Current 0 7.843 -7 mA a count of 128 is about 1000 mA 5-Volts 0 0.0235 0 volts a count of 213 = 5 volts ----------------------------------------------------------------------- PCSAT2 TELEMETRY DESCRIPTION 4 Mar 2005 ----------------------------------------------------------------------- Not realizing I had done all this work, I did another complete write up of the telemetry from scratch. Here is the new version and this one is derived from the actual code in our PCSAT2 decoding software used during all testing. So if there is any difference between the above file and the below file, I guess the below file should take precedence. Define Function for Temperature: Tof(V) = .00001 * V ^ 3 - .0034 * V ^ 2 + .7134 * V - 33.49 Telemetry Format is: T#515,135,134,001,138,001,11111111,0010,1 T#nnn is serial number Then five 3 byte decimal values Then eight bits which default to 11111111 1st bit = 0 means 96 hour timer toggle is set 2nd bit = 0 forces reset of opposite TNC 3rd bit = 0 means RX heaters are on 4th bit = 0 means VHF transmitter is enabled 5th bit = 0 toggles state of Shunt Reference 6th bit = 0 means PSK-31 is enabled 7&8 bits= 01 means FM Repeater is forced on 00,11,10 mean nothing Next is a comma Next is SRFF,Z Where S bit is Solar Experiment Reset Where R bit is RESET 8 hour timer (shuts down system) Where FF are they two frame bits IF Frame is "00" THEN RXa Current = 2 * value1 RXb current = 2 * Value2 B3volts = Value3 / 20.07 TNCa current = 2 * value4 TNCb current = 2 * value5 IF Z bit is a "0" THEN ArmB2 = -1 IF Frame is "01" THEN BatTemp = Tof(value1) CaseTemp = Tof(value2) TXa current = 5 * value3 - 5 TXb current = 5 * value4 B1-volts = value5 / 19.86 IF Z bit is "0" THEN ArmA2 = -1 IF Frame is "10" THEN TXa temp = Tof(value1) TXb temp = Tof(value2) B2-volts = value3 / 20.01 RX temp = Tof(value4) TNC temp = Tof(value5) IF Z bit is "0" THEN ArmB1 = -1 IF Frame is "11" THEN B4-volts = value1 / 10 Bat current = INT(-22.44 * value2) + 2.27 * Tf + 2842) Load current = INT(15.43 * value3 + 20) Solar current= INT(7.843 * value4) - 7 5volt ref = value5 * 5 / 213 IF Z bit is "0" THEN ArmA1 = -1 ELSE ArmA1 = 0 IF 5volt ref is < 1 volt THEN set 48 hour warning Notice TF in the Battery Current equation. This is the temperature of the FTSCE experiment which must be obtained by other means. Assume 0 deg C if not avail de WB4APR, Bob