GLAST/LAT > DAQ and FSW > FSW > Doxygen Index > LTC / V6-2-1
Constituent: ltct Tag: sun-gcc
#include "LTC/LTC_tlmdefs.h"
Include dependency graph for ltc.h:
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| unsigned int | LTC_initialize (void) |
| Initializes and configures thermal control software. | |
| unsigned int | LTC_shutdown (void) |
| Release resources associated with LTC. | |
| unsigned int | LTC_StartTask (void) |
| Start Thermal Control processing. | |
| unsigned int | LTC_StopTask (void) |
| Stop Thermal Control processing. | |
| unsigned int | LTC_GetTlm (LTC_DiagLTC_Tlm *tt) |
| Retreive telemetry data. | |
| unsigned int | LTC_GetConfigFile (unsigned int *fid) |
| Get LTC configuration file ID. | |
Control is accomplished by reading-in radiator interface (RIT) and heat pipe reservoir temperatures via the PDU, applying these temperatures to a control algorithm that calcuates whether to turn on or off the heat pipe reservoir heaters, and then commanding the heater on/off bits in the SIB. There are twelve heat pipes numbered or indexed internally as 0 - 11. The temperature sensors and on/off switch bits must be consistent and refer to the same heat \ pipe. The on/off bits in the SIB Heater Control Register refer to the left and right heater. Thus the association of heater index to SIB HCR bits is as follows: 0 - Left Heater 0, 1 - Left Heater 1,..., 5 - Left Heater 5, 6 - Right Heater 0, 7 - Right Heater 1,..., 11 - Right Heater 5. The temperature sensor addresses must be setup consistent with this numbering. For reference to the LAT, the left and right radiators refer to the -Y and +Y radiators, respectively. The VCHP numbering used in the instrumentation list for the -Y radiator is VCHP 0 is closest to -X and for the +Y radiator 0 is closest to +X. Thus heat pipe 0 is on the -Y radiator in the most -X direction, heat pipe 5 is on the -Y radiator in the most +X direction, heat pipe 6 is on the +Y radiator in the most -X direction and heat pipe 11 is on the +Y radiator in the most +X direction.
The temperature sensors are read using the monitor capability of the PDU. The PDU is capable of monitoring 160 quanities, but only contains 20 12-bit ADCs. Thus the values to read or monitor are organized into eight groups of 20 different sensors per group. When requested, an entire group is digitized and values read into the 3 PDU environment registers. The sensor values within a group are referenced according to ADC banks 0 - 19 consecutively in the environment registers. Thus the value for a particular sensor is identified by its group and ADC bank number (e.g. +Y_VCHP_DSHP_INTF _T_1 is group 5 and ADC bank 7). Futhermore, the temperature sensors required for LTC are scattered among all eight groups as defined by tables in the PDU document. The environment registers are 96 bits (3 unsigned ints) wide. Environment registers 0 contains 7 values (ADC Banks 0 - 6), register 1 contains 7 values (ADC Banks 7 - 13) and register 2 contains 6 values (ADC Banks 14 - 19).
The pduTable defined below is orgnized by group and defines for each group the ADC bank numbers for temperature sensors values required by LTC from the given group. This table also associates each measurement with a particular heat pipe and measurement type (RIT or Reservoir).
Once each LTC cycle, the PDU is commanded via the Monitor Register to digitize all the eight groups - one at a time. For each group, the group number is written to the PDU monitor register, and after a delay (~140 usecs) the 3 environment registers are read into the pduReg array. The PDU commanding is accomplished using LCB command and response lists that are precomputed at initialization and submitted each LTC cycle. The temperature sensor values used by LTC are extracted from the register array and stored into the heat pipe variables for used by the LTC control algorithm.
Temperature sensors are connected (hardware wise) with heat pipes. Each heat pipe has a primary and redundant reservoir heater, and a primary and redundant DSHP and XLHP sensors. The control algorithm uses a reservoir and RIT temperature for each heat pipe. Anyone of the primary and redundant DSHP and XLHP sensors may be selected for the RIT temperature of a heat pipe, and any primary or redundant reservoir heater sensor may be selected for the reservoir tempearture of a heat pipe. Sensors may be mapped via the HP Configuration File to a different heat pipe then their hardware connection. A sensor is defined by its connected heat pipe and sensor type (DSHP, DSHP Redundant, XLHP, XLHP Redundant, primary reservoir heater and redundant reservoir heater. The mapping of sensors is defined in the HP Configuration File, and is stored in the ritSel and resSel variables of the structure for each heat pipe.
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Get LTC configuration file ID.
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Retreive telemetry data.
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Initializes and configures thermal control software.
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Release resources associated with LTC.
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Start Thermal Control processing.
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Stop Thermal Control processing.
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1.4.4