Setpoint Profiles (for Reflow et al)

[rocketscream]

Look at the Dashboard menu on the LCD? Check the input parameter, it should be going up.

[Brett]

Is there a simple thermocouple test that I have missed?

can you confirm that you have set the osPID to read from the thermocouple input rather than the thermistor input? when connected, this setting will be visible on the front-end config tab

[Maddox]

I did select thermocouple on the input.

The input parameter line was not changing.

I will recheck all the connections and try again.

I guess I can write this when I get a chance - a little test program that just displays the temperature on the LCD would be a useful tool!

[Brett]

I guess I can write this when I get a chance - a little test program that just displays the temperature on the LCD would be a useful tool!

the 2nd item on the osPID dashboard is the current value of the input. is this not working? (menu reference)

[Maddox]

Well, I swapped the thermocouple leads and it started to work

As soon as I select the relay on the config menu, it begins to switch at a regular .5 second rate. I started the sample profile and the temperature rose above 50, then 100, and kept on going, still switching at .5 hertz. Here's the picture:

http://www.flickr.com/photos/77705680@N06/7117627567/

How do I get the PID output to engage to control the temperature? I know it must be something simple - would be grateful for a nudge in the right direction.

[Maddox]

OK - sorry - it was on manual, not automatic. A case of RTFM

[Brett]

OK - sorry - it was on manual, not automatic. A case of RTFM

thank you for posting this! you will not be the last person to do this. that is, until I put some logic in the firmware that flips the mode automatically when the profile is started.

so that I don't forget, I've added it as an issue on github.

[Maddox]

I loaded the reflow profile you had posted earlier, sent it to the osPID, and ran it:

Code: Select all

[profile name, 7 chars max]
3, 100, 0      //step (3) setpoint to (100) and immediately go so the next step
2, 0, 0      //we have no idea where the oven temperature was at the start, so wait (2) until it crosses the setpoint from the previous command (100)
1, 217, 100      //ramp (1) the setpoint to 217 over the next 100 seconds
2,0,0        //because the oven temperature is likely lagging behind the setpoint ramp from the previous step, wait (2) until it actually GETS to 217 before proceeding the next step
1, 245, 20      //ramp (1) the setpoint to 245 over the next 20 seconds
3, 255, 30      //step (3) setpoint to 255 and wait 30 seconds
1, 210, 20      //ramp (1) the setpoint to 210 over the next 20 seconds
3, 75, 30      //step (3) setpoint to 75 and immediately go so the next step
2, 5, 3      //wait (2) for input to be within (5) degrees of the of the last setpoint (75) for (3) seconds before proceeding to the next step (END)

http://www.flickr.com/photos/77705680@N06/7118700487/

I haven't run autotune yet, but I thought I'd get feedback from the more experienced on how this profile looks and any suggestions for tuning and or operation?

[Brett]

I haven't run autotune yet, but I thought I'd get feedback from the more experienced on how this profile looks and any suggestions for tuning and or operation?

it's hard to get an idea for how well the tuning parameters are working, since the output is pegged at 100% or 0% for a large portion of the profile. the toaster is giving all it can at it still can't achieve that heat rate. if you slow down the ramp rates (increase the 3rd number in the rows that begin with "1",) you'll be more likely to a) actually achieve the requested setpoint, and b) see the pid moving the output.

[Maddox]

it's hard to get an idea for how well the tuning parameters are working, since the output is pegged at 100% or 0% for a large portion of the profile. the toaster is giving all it can at it still can't achieve that heat rate. if you slow down the ramp rates (increase the 3rd number in the rows that begin with "1",) you'll be more likely to a) actually achieve the requested setpoint, and b) see the pid moving the output.

I'll try the longer ramp times. On the ramp down (like going from 255 to 210 in 20 seconds, and then to 75), it seems to take a long time for the oven to cool off - I assume a little assist by opening the door is the the common way to address this? When I get everything figured out, I'll post the details on which oven I used and how I wired it up.

Thanks!!!