I had Kp set to 100 when I first observed this, and have been setting it to other large positive numbers to see if there is some logic in the repro. (reason so high: I have a 30-watt mat heater trying to take on 40 gallons of water, admittedly underpowered, and I was trying to cause oscillations around the setpoint so that I could figure out ultimate gain).
Here is a screencast of a repro: https://goo.gl/2UK5pn1. In the video I set Kp to 200, verify in the algorithm window and in the log, then come back to advanced settings. If I click "Update from Core" the value has gone negative again. When Kp = 200 the associated negative value = -56, and if Kp = 400 the negative value = -112 (so ironically the behavior is proportional!)
The JSON value in the Control Algorithm tab says the expected value, even when the Advanced Settings box shows a negative value.
Bugreport from DanCook:
I had Kp set to 100 when I first observed this, and have been setting it to other large positive numbers to see if there is some logic in the repro. (reason so high: I have a 30-watt mat heater trying to take on 40 gallons of water, admittedly underpowered, and I was trying to cause oscillations around the setpoint so that I could figure out ultimate gain).
Here is a screencast of a repro: https://goo.gl/2UK5pn1. In the video I set Kp to 200, verify in the algorithm window and in the log, then come back to advanced settings. If I click "Update from Core" the value has gone negative again. When Kp = 200 the associated negative value = -56, and if Kp = 400 the negative value = -112 (so ironically the behavior is proportional!)
The JSON value in the Control Algorithm tab says the expected value, even when the Advanced Settings box shows a negative value.