Is there anything that would cause an STXL-16200 camera cooler to turn off without being told to by software? This has been happening many (but not all) nights after my imaging sessions end. In the driver "Debug Log" I enabled "CC Temperature" and "MC Temperature" and can see "CC_SET_TEMPERATURE_REGU2" and "MC_REGULATE_TEMP" commands when I manually enable or disable cooling (via SGPro), but those commands don't exist when the temperature started rising (apparently on its own). Hundreds of entries prior to these had "imgCcdPower" around 75, then started getting the following, with the "imgCcdTemperature" eventually reaching ambient and "imgCcdPower" reaching 0: At t = 479581.475: ========================= At t = 479581.483: CC_QUERY_TEMPERAT_STATUS Params: TEMP_STATUS_ADVANCED2, Results: ccdSetpoint=-20.0, imgCcdTemperature=-20.0, imgCcdPower=67.7 At t = 479584.727: MicroCommand : MC_TEMP_STATUS At t = 479584.739: QueryTemperatureStatus -> TEMP_STATUS_ADVANCED or TEMP_STATUS_ADVANCED2 At t = 479584.747: STXGetTemperatureData : destAddress: 0x30, STX_TEMP_DATA len: 60, subCmd: 2 At t = 479584.756: QueryTemperatureStatus -> MicroCommand(MC_TEMP_STATUS, pDllGlobals->cameraID, NULL, &qtsr)) res: 0 At t = 479584.767: ========================= At t = 479584.776: CC_QUERY_TEMPERAT_STATUS Params: TEMP_STATUS_ADVANCED2, Results: ccdSetpoint=-20.0, imgCcdTemperature=-19.8, imgCcdPower=59.7 At t = 479588.023: MicroCommand : MC_TEMP_STATUS At t = 479588.032: QueryTemperatureStatus -> TEMP_STATUS_ADVANCED or TEMP_STATUS_ADVANCED2 At t = 479588.043: STXGetTemperatureData : destAddress: 0x30, STX_TEMP_DATA len: 60, subCmd: 2 At t = 479588.052: QueryTemperatureStatus -> MicroCommand(MC_TEMP_STATUS, pDllGlobals->cameraID, NULL, &qtsr)) res: 0 Also, how do I determine the date/time of an entry? Eric
Overheating will cause it to turn off - it may be trying to protect itself. This would be my top guess. Insufficient power might cause it to turn off - eg low voltage due to high current usage, possibly inadequate wiring, or a failing power supply. Weather lately has had extreme temperatures. (I seem to remember your equipment is in New Mexico). You need to work out the maximum reasonable setpoint. The camera's Delta T (maximum temperature difference) is somewhere between 50 and 60C (dirt, age, altitude and air density all have an impact). So doing the math: -20C setpoint + 50C = +30C max outside temperature (or 86F). If it is hotter than 30C, the camera just can't move enough cooling air through the fan and across the heatsink. It will likely shut itself down. I can't help with the SGP log.
Colin, You may be on to something. There have been several days where temperature inside the observatory got to around 100 F. Would you please check with the engineers or others to see if the cooler will in fact shut down, and if so, is it based on ambient temperature or % cooling (it never got over 75.7% cooling), or something else? The log entries above are from the camera, not SGP. Would you also please ask what the "t" numbers represent? Seconds since Jan 1, 1970, for example.
That's 38C. A setpoint of -20C means you've got a Delta T of 58C. The camera's best performance is 60C at standard temperature and pressure at sea level. At 2000m, you've exceeded it. It does in fact shut down. Already told you so. Something else. The thermoelectric cooler (TEC) ability to pump heat is a function of current, temperature difference between the two sides, operating voltage, and other factors. The % cooling is a simplified representation of what is going on in the camera. The camera is does not have a way to sense barometric pressure, fan CFM, ambient temperature, humidity, etc. I didn't recognize that was an SBIG Driver Checker log - some of the usual stuff isn't in the excerpt. Apologies for missing that. The time stamp units are seconds, since the beginning of that log session, starting from when the driver is invoked. So about 5.5 days (497581 / 60 / 60 / 24) since some program initially accessed the driver. It's not related to date/clock time.
Colin, Thanks for your detailed answers. They make total sense. Last time I visited the observatory in NM (you have a good memory) I took a roof fan to cool the inside, but didn't get a chance to install it. I will do that next visit to avoid the TEC from shutting down. Sorry for misreading your original statement that the cooler will shut down in high heat. Eric
You could also adjust the setpoint of the camera to something like +15C during the day, so the fan runs, and then start cooling the camera in the early evening to the desired temperature.
