The unit has the following fans:
Two Intake Fans (Delta QFR1212GHE 210.4CFM)
These are ran at approximately 66% speed and are located in the lower right hand side of the unit.
Exhaust Fan (Sunon PF92381BX-000U-S99 182.4 CFM)
This is ran at 100% (without external filter) and is located in the left rear at the exhaust port.
Air Assist Fan (Delta THA0142AD 20.6CFM)
This is ran at 100% and is located at the rear of the laser head sled. This is to assist in clearing away the products of combustion and blowing out small flames during a run. It does not assist in cooling.
Lens Purge Fan (Sunon MC20080V1-000U-A99 1.6CFM)
This is ran at roughly full speed and is located on the laser head assembly. This is to clear products of combustion from inside the lens assembly. It also does not assist in cooling.
For temperature sensors, there are several.
- The accelerometers (LIS2HH12) located on the lid camera board, the control board, and the laser head each have an embedded temperature sensor.
- The interconnect board (left side of unit) has a LM75B compatible temperature sensor.
- The power supply
- The coolant loop has two temperature sensors and a heating element. One sensor is upstream and the other is downstream of the heater.
That covers the “what”. The “when” seems to depend on what mode the device is in at the time.
The device sends a constant data stream (telemetry) to the mothership with all of the various sensor values. If these are showing the temp to be too high, the web interface will alert you.
If the device is in the middle of a job, the trigger points come from the job file itself. The file contains thresholds for each sensor. There appears to be a minimum and maximum value for starting a job as well as for pausing a job. I haven’t fully deciphered them all, but you can grab one for yourself, decode what is in it, and update the list if you figure out what any of them are.
From what I’ve seen, most of the values for the sensor trip points seem to be maxed out, which effectively nullifies their contribution to the shutdown. It seems that the coolant temperature is the only one that is considered (your question #2).
My guess is that the Orange light comes on when the device itself triggers the cooldown based on job settings, and it does not come on when the service detects it via telemetry.
As to what the exact temperatures are that the device will run at? Your guess is as good as mine. Glowforge gives the technical specs, but these don’t seem to align with the actual operation of the unit. Though, based on the numbers I can glean from looking at the job files, it seems to be 10-25C (50-77F).
This did seem to be the case the last time I tested it (which was a few firmware revisions ago). It is possible that this has changed, though I have not confirmed one way or the other.
There are four IR sensors on the lid LED strips. There didn’t seem to be any mention of these in previous firmware releases, and I haven’t examined the newest release to see if that changed. I’m not sure about the utility of these, and I would be impressed if GF was able to get them to operate reliably as flare-up sensors.