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Old 17-03-2017, 10:45 PM
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luka
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Join Date: Apr 2007
Location: Perth, Australia
Posts: 1,164
New firmware (0.4L) and driver (0.6.5L) are out in the usual spot.

I have added the option to adjust the Kp, the proportional gain of the PID loop. As I don't have any cooling the driver is experimental and untested.

Pat and Gilles, if your cameras are working can you test the firmware/driver. You will need to:
1. Set the starting cooling power to zero and start the cooling. Record the time profile of the temperature going down. You don't need to go very low in temperature, 10-15 degrees lower than the ambient temperature is probably enough to test the driver.
2. Let the camera warm up.
3. Modify the Kp parameter and redo the test.
Default Kp is 0.04, try setting it to 0.1 or even larger. Note that if the temperature oscillates and goes crazy you have gone too high.
Please monitor the temperature at all times during the test, the driver is experimental.

With a larger Kp the temperature should go down quicker.

Regarding the tuning of Kp, the usual guide is to keep increasing it until you see oscillations. Then halve the value and that's it. There is lots of material on Google about tuning the PID loops. Again note that we only have the proportional term.
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