damper only working on manual fan mode

KeithC

New member
can someone please help on this? beyond frustrated, I finally got the SG90 servos to build the damper fan (the 3d printed one Bryan has on the store) with the delta fan from the kit as well. it's only rotating / working in manual mode. it stays closed in auto or whatever its sitting at when you switch modes. I'm to the point of giving up completely, been stuck on this all day. wound up using the old stoker for the ribs over the holiday because I'm really frustrated with the overshooting and now servo issues. followed the instructions (as best I could) on initial blower & servo setup on the wiki. thanks.

Screen Shot 2020-09-08 at 8.20.09 PM.png
 

Bryan Mayland

TVWBB Hall of Fame
I'm not sure how that's possible, that the servo would only work in manual mode. The code it is running through is exactly the same, where auto mode calculates what the output needs to be and calls commitPidOutput(), manual mode skips the calculation and calls commitPidOutput() using a fixed value. I've just even looked over the code to confirm there's no special code that can prevent the servo from operating in normal/auto mode. I've also just entered your settings into a HeaterMeter here and a servo moves in both modes. Is the servo behaving weirdly at all when it moves in manual mode? Sticking, jittering a lot, jumping between positions?
 

KeithC

New member
@Bryan Mayland thanks for looking, I was losing my mind last night trying to figure out in the settings what would trigger this. I still don't know what was going on, but swapped the cable (made a from scratch Cat 6 cable) and it started working. Put the old cable on and it was still working.

the only thing I'm seeing now, is the blower supposed to be variable speed too or not? it seems like it's full blast when it comes on or pulses at the lower outputs. thanks.
 

Bryan Mayland

TVWBB Hall of Fame
The blower is variable speed (variable voltage in Voltage output mode, which is the default). You have your blower min set to 10% which turns the blower on and off when it is below 10%, running at 10% speed for 1-10 seconds in a 10 second cycle to reach the requested output. Maybe that's what you're seeing? When it turns on, it also runs at 100% speed for a short time (100ms?) to make sure it spins up before throttling down to the requested output.
 

KeithC

New member
I made an adapt-a-damper with the HM kit fan. did pork chops (2" thick!) last night and here's the graph - a lot better than what I was seeing! a couple of small overshoots. I lowered the temp because it seemed like fan was running too much when it was at temp but settled down.

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