Reconfigurations ---------------- Edited: 2005/11/29 Changed the comment on individually controlled heaters and listed location of Matra document in this section 2005/11/23 Based on input from Ton/Bertrand: Clarified first section, added "i.e. the B side OBDH bus...". The following did not change the content of the document: Moved note about inhibiting sub htr/exp LCL monitoring up into "corrective action" list under sub htr section. Reformatted experiment monitoring section to be consistent w/first two sections in terms of how cases/corrective actions are listed. 2005/11/22 Clarified section on Sub Heater Monitoring, including table of circuits/heaters (inserted "Sub Heater" in 2nd last column). 2005/11/09 Clarified that all primary thermistor values violating on-board limits will cause a reconfiguration. 2005/11/02 Cross-checked list of circuits against Matra document (the circuit diagram and associated tables in the ESR Notes binder) A payload (PLM) remote terminal unit (RTU), or PRTU, reconfiguration means that the PRTU is set to use the B side, i.e. the B side On Board Data Handling (OBDH) bus is used for communication between the spacecraft and the instruments. The substitution heaters are controlled separately and are not affected by a PRTU reconfiguration itself. RTU reconfigurations disrupt the clock signal going through the reconfigured RTU. This will affect the clocks of many instruments, so the FOT will need to send the OBT to: CELIAS, CEPAC, LASCO, MDI, SWAN, UVCS (note: GOLF ignores all timing input except the first daily pulse after switch-on so its timing will lag after reconfigurations). MDI may need to restart its structure program and CDS may have problems similar to those seen occasionally during submode changes. LASCO may have problems as well. Thermal Monitoring ------------------ Thermal monitoring is done on board the spacecraft. The on-board thermal monitoring uses a single pair of high and low values for each thermistor/mnemonic that is selected for a given circuit. The on-board high and low values are somewhat wider than the ground-based red limits, and causes an automatic corrective action when triggered. The on-board monitoring of individual circuits may be switched on or off (enabled/disabled). Note also that each circuit usually has two thermistors, one prime and one redundant. For most, the prime (mnemonic ending in A) is the one selected for the circuit, in which case the redundant mnemonic cannot cause a corrective action. On the ground, the ground system monitors defined yellow and red limits. These limit violations do not cause an automatic corrective action - they are flagged by the ground system and acted upon by the FOT, according to existing contingency scripts, standard operating procedure (notification: immediate if red, next workday if yellow), or other instrument team instructions. The corrective actions fall into two categories, depending on the nature of the violation: Case 1 occurs if the thermal circuit that violates the on-board monitoring thresholds is linked to a substitution heater. Corrective actions, if enabled, are: PRTU is reconfigured The instrument that had the circuit violate limits is turned off at the LCL level PLM nominal heaters are turned off PLM heater control is switched to the B side The instrument that had the circuit violate limits has its substitution heater turned on (on the B side) All thermal monitoring, experiment LCL monitoring, and substitution heater monitoring functions are inhibited Case 2 occurs if the thermal circuit that violates on-board monitoring thresholds is not linked to a substitution heater. Corrective actions, if enabled, are: All 3 RTU's are reconfigured All heaters are turned off All heaters are switched to the B side All thermal monitoring functions are inhibited Substitution Heater Monitoring ------------------------------ When this monitoring is enabled for a circuit, it expects the substitution heater to be off. If the heater is found to be on, it will trigger the following corrective action: PRTU is reconfigured Nominal heaters for all instruments are turned off PLM heater control is switched to the B side Substitution heater and experiment LCL monitoring functions are inhibited. NOTE: Individually controlled substitution heater on/off status is not monitored by COBS. The ground config mon monitors both the individually and collectively controlled heater settings. NOTE: The list of all collectively controlled substitution heaters is attached. Experiment LCL Monitoring ------------------------- Experiment LCL monitoring will trigger when there is a status violation in an instrument's LCL. When this monitoring is enabled, it checks to see if an instrument is powered on or off, depending on what it is set to for each instrument (normally, it checks that all nominal LCL's are on and all redundant LCL's are off). It will trigger for one of two reasons: Reason 1 - Instrument LCL found OFF when expected ON. Corrective actions are: PRTU is reconfigured That instrument's LCL is commanded OFF That instrument's nominal substitution heater(s) are activated Substitution heater and experiment LCL monitoring is disabled for that instrument. Reason 2 - Instrument LCL found ON when expected OFF. Corrective actions are: PRTU is reconfigured All instruments are turned OFF All instruments' nominal substituation heaters are activated Substitution heater and experiment LCL monitoring functions are inhibited (all instruments). Note: ESA technical note for RTU Reconfigurations can be found here: http://sohowww.nascom.nasa.gov/soc/rtu_explanation.html Table of Thermal Circuit/Heater Information ------------------------------------------- Sub Heater Selected Instrument Circuit Collectively Thermistor Controlled? Mnemonic ________________________________________________________________ CDS1 62 No QTCI1A CDS2 & CDS3 63 Yes QTCR3 CTOF-C/M/S-TOF 64 No QTFI3A MTOF 65 No QTFI2A STOF 66 No QTFI1A STOF E/DPU 67 Yes QTFR4 GOLF Sensor 68 No QTGI1A GOLF EB1 & EB2 69 Yes QTGR2 LASCO COB 70 No QTLI2A EIT 71 No QTLI1A MDI OP 73 No QTMI1B MDI EP 74 No QTMI2 CEPAC ESU 75 No QTHI1A SUMER TDC 76 No QTSI2A CEPAC EPHIN E/LVPC 78 Yes QTHR3 SWAN 1 79 No QTNI1A SWAN EB 80 No QTNI2A SWAN 3 81 Yes QTNR3 SUMER 1 82 No QTSI1A SUMER2 & SUMER4 83 Yes QTSR3 UVCS Sensor 84 No QTUI1A UVCS REU 85 Yes QTUR2 VIRGO Sensor/EPS 86 Yes QTVR1 LASCO LEB 87 No QTLI3A