Command line access for servo control?

[Steve_M]

I wanted to demo the servo control to some friends and co-workers. Rather than using the button on the HM to step the servo in 5% increments, I was wondering if it was possible to control the servo from the command line where I could use a for loop to continuously go from 0% to 100% and back to 0% in a smooth fashion.

 

[Bryan Mayland]

You can just use the manual mode setpoint command: /sp=-X

/sp=-0
/sp=-1
/sp=-2
/sp=-3
/sp=-4
etc

Is that what you're looking for?

 

[Steve_M]

I was looking to set the blower speed % rather than the setpoint.

 

[Bryan Mayland]

Setting a negative setpoint sets "manual mode" which directly sets the output percentage.

 

[Steve_M]

Ahh, I see now. I didn't see that it was negative setpoint value in your first post.

Thanks!

 

[Steve_M]

Here's my script

# cat ./updown.sh
#!/bin/sh
for i in `seq 0 2 100` ; do lmclient LMST,sp,-$i ; sleep 1 ; done
for j in `seq 100 -2 0` ; do lmclient LMST,sp,-$j ; sleep 1 ; done

The busybox version of sleep doesn't support tenths of a second.

 

[Bryan Mayland]

You could always do it in LUA if you want sub-second delays

#!/usr/bin/lua

local nixio = require "nixio"

require "lmclient"
local lm = LmClient()

for i=0,100,2 do
  lm:query("$LMST,sp,-"..i, true)
  nixio.nanosleep(0, 500000000) -- delay 500ms
end

for i=100,0,-2 do
  lm:query("$LMST,sp,-"..i, true)
  nixio.nanosleep(0, 500000000) -- delay 500ms
end

lm:close()

 

[Steve_M]

Awesome! Thanks.

 

[Steve_M]

Turns out about 500ms is the fastest the fan/servo will respond.

I was trying to get a nice smooth 0 to 100 and back to 0 in about 15 seconds, kind of like what might be considered to be the HM in "demo mode".

 

[RalphTrimble]

Set the pit temp so the servo/fan is at 100% then disconnect the pit probe, she will shoot from 100% to 0%, plug the pit probe back in and she will shoot back to 100%. I know that's not exactly what you wanted but the movement will happen fast and smoothly....

 

[Bryan Mayland]

Yeah now that you mention it, Steve, internally I think it just queues the output change for the next period. Periods only happen every second so that's probably why you're seeing that behavior.

If you changed GrillPid::setPidOutput() to include the line commitPidOutput() at the end it would take effect immediately although that would shorten the blower "long pid" (pulsed on and off) function.

 

[Steve_M]

Set the pit temp so the servo/fan is at 100% then disconnect the pit probe, she will shoot from 100% to 0%, plug the pit probe back in and she will shoot back to 100%. I know that's not exactly what you wanted but the movement will happen fast and smoothly....

I can already control that type of movement remotely.