The LinkMeter Snapshot and YOU

Gary V

TVWBB Member
Brian,
When my grilled reached temp, i noticed i could not maintain temp. Temp started dropping off and never recovered even when the servo showed it was open 50%. Thought maybe the thermocouple was flaky so i changed it. No change. When the temp dipped, servo would open and the fan would show 0% on the graph. So i checked the invert and then when the servo opened for more air the fan followed. the grill would then maintain temp. Then i let it settled for 15 minutes and control was working fine. I decided then to make a tweak to the "I" value from .0032 to .0034 and waited for the change, and 10 minutes after the change the controls went nuts and the temp dropped out and the controller locked up. I rebooted and the controls never really recovered. I reloaded 20200214 and all is working we. Back to normal. I do not need to check invert box for fan. Very interesting. The firmware i was using was the latest from the download page.today`s cook.jpg
 
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Bryan Mayland

TVWBB Honor Circle
Well that certainly is weird, but I've never seen anything like that or seen a HeaterMeter lock up in like 8 years. Those temperature drops look very suspect, unless you're opening the lid or something at those points. Also were you adjusting the setpoint or is something else going on there?

I've tried all the combinations I can come up with and even changing all the parameters all over the place I get exactly what I manually calculate the output should be. We're both on the same version too, 20200214 which is the latest snapshot on the download page.
 

Gary V

TVWBB Member
here is more for the fire. never opened the lid till cook was done at 2:30 pm. first major drop i did a reboot and then waited. the second one i changed probe when it dropped. when it started dropping again i reload the 20200214 firmware. the last 2 who knows and then it started to stabilize when it started to get up around 40 degrees. As you can see early on the fan was acting strange. Way to fast on graph, even though it was hardly running. Problem stabilized after reload of image, but not even sure with that. Never experienced this either. I have re terminated the connector on the thermocouple probe in case that might have been an issue, but that connector under a magnifying glass looked good. Only other thing which could been an issue was i started cook when it was in the 20`s and a little wind, but not enough wind to cause issue with damper. I did order some new servos, hope according to tower pro website the dealer they recommend sells real TP parts. Noticed the current servo does have temp drift problem so i will replace. Found that only after control stabilized for the rest of cook.
 

Bryan Mayland

TVWBB Honor Circle
I don't know what's going on with your setup, especially because reloading the firmware does nothing apart from reset the AVR and database. The Pi and database exist outside of the control function of the device, so there's no reason to reload its firmware. Rebooting the AVR resets all the internal state, which may reset something which is creating the symptoms you're seeing? There is a "Reboot AVR" button in the Configuration page that you can try as well, instead of reloading the firmware. When you say you rebooted, did you reboot or did you power cycle the device? A reboot would just restart the external processes but a power cycle would also include an AVR reboot.

If you want to pursue this further, please make a new thread about it instead of posting here since I do not believe this to be related to the snapshot firmware.
 

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