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3.5.1.2. "Wait & Verify" Instruction with Time-out and Retry
This TC instruction allows to verify in the telemetry flow that a telecommand was correctly executed by the
spacecraft.
The telemetry flow reflecting telecommand execution is selected by a TCU configuration command received on
the Control port.
Byte offset, mask and expected value:
The words to consider in the telemetry flow are defined by their byte offset in the frame. Each word may be up to
32 bits long, using successive Telemetry Data Fields as necessary (MSB's first). Each word is ANDed with the
associated mask before being compared to the expected value. All words are garanteed to be picked up in the
same minor frame. Successive frames are considered till the verification is successful or time-out expiry.
TC message retransmission:
If the time-out has elapsed before the verification is successful, and if the number of retries specified by the
instruction is not 0, the TC message from the last TC request is re-transmitted to the spacecraft.
If the number of retries has been reached, status Locked-out is posted in the TCU monitoring table and all
successive satellite TC requests and TC instructions in the queue are rejected till a « TCU Unlock » instruction is
received from the Telecommand Client.
3.5.1.3. "Execute" Instruction
This TC instruction allows to send execute pulses to the spacecraft. The following parameters are specified by
the instruction: number of pulses, pulse duration and pulse period. The Execute tone frequency is programmed
via the Control port.
3.5.1.4. "Pause" Instruction
This TC instruction forces the CORTEX CRT Quantum to wait for the specified time interval. May be used to
insert calibrated time intervals between two consecutive TC messages.
3.5.1.5. "Wait for Absolute Time" Instruction
This TC instruction allows to process a satellite TC request at a precise date and time. The timing accuracy
depends on:
other sources of error being in the range of ± 2ms.
Processing of TC instructions and requests in the queue is stopped until the specified date and time are reached
or when a « Wait for Absolute Time » abort command is received over the Control port.
Status Wait for Absolute Time is available in the TCU monitoring table.
3.5.1.6. "TCU Unlock" Instruction
© Safran Data Systems
COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
the idle mode (ON or OFF),
the idle pattern length (the TC encoder always transmit an integral number of idle patterns),
the preamble length,
the bit rate,
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Safran Data Systems
.
Ref.
DTU 100042
Is.Rev.
5.17
Date:
Dec.
03, 2021Sept. 30, 2021
Page 134
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