Imperx LYNX Series Hardware User Manual page 214

(d) Wait for ~30 seconds.
(e) Sample TEC temp for a comparison reading (comparison-temp-sample).
(f) If (baseline-temp-sample - comparison_temp_sample) ≥ Delta_Temp °C
then BIST test passes. Otherwise the BIST test fails, and the TEC cooler is
shutdown. The Delta_Temp value is determined from the initial baseline
temperature reading:
(i) For baseline_temp_reading ≥ 20 °C, Delta_Temp = 3 °C.
(ii) For 10 °C ≤ baseline_temp_reading < 20 °C, Delta_Temp = 2 °C.
(iii) For baseline_temp_reading < 10 °C, Delta_Temp = 0 °C (BIST
Ignored).
If Self-Test "passes", the TEC unit is released to the user for normal operation, and
a TEC Status: "Active" is returned. Otherwise, the TEC unit is turned off to protect
the camera and "Shutdown" status is reported. The only way to exit TEC
"Shutdown" mode is to re-power the camera.
Active Mode:
This is the normal operating mode of the TEC camera. A returned TEC Status
"Active" indicates that the TEC unit is cooling properly.
Shutdown Mode:
If the TEC BIST "fails", then the TEC cooler is turned off, and TEC Status is
reported as "Shutdown". A secondary protection mechanism samples the PWM
"Fault" flag in Constant Power Mode. If the PWM "Fault" flag is detected for over
7.5 seconds, then the TEC Cooler is shutdown.
Shutdown mode indicates that the TEC unit is not cooling properly, temperature
read back is broken, or extreme ambient temperatures are causing a BIST failure.
The "Shutdown" mode can only be exited by re-powering the camera.
Protection Mode:
Self-protection features are built into the TEC Controller firmware to reduce
damage to the camera for high TEC current for extended periods of time. During
"Protection" mode, the TEC cooler is set to a safe (minimal) value and all power,
temperature, and mode settings are ignored. The "Protection" mode can only be
exited by re-powering the camera.
(a) Constant Temperature Mode: If constant current greater than 2.0A is
detected for over ~3.5 minutes, then the TEC Cooler is set to a safe
(minimal) value of ~6.0W , and TEC Status "Protection" is reported.
(b) Constant Power Mode: This mode has built-in hardware limits based on
the maximum power value setting of 20W. Self-protection is not required in
this mode.
LYNX Hardware User's Manual
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