Ramp Setpoint Mode not working

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ocluke
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Ramp Setpoint Mode not working

Post by ocluke » Fri Oct 05, 2012 9:53 pm

After several attempts, I have been unable to get the Ramp Setpoint Mode to work for crash cooling. I'm guessing I'm doing something wrong, but there are so few settings for that feature that I can't imagine what it is that is setup incorrectly.
  • I have the correct Output checked.
  • I have "Enable" checked.
  • I set the Start Temp and End Temp (in this case 62 and 40, respectively).
  • For Ramp Time, I used 24:00:00, assuming that means to ramp it down 22 degrees over a 24 hour period.
What ends up happening is the fermentation fridge will immediately begin dropping to the start temperature value of 62 (the hysteresis was set to hold at 65), but then it will just hold it at that temp indefinitely; it never drops it below the start value. On a side note, it also changes the output temp hysteresis setting to the new ramp Start Temp.

If anyone has thoughts on what I am doing wrong, I would appreciate any input. I've never once been able to get this feature to work.

ocluke
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Re: Ramp Setpoint Mode not working

Post by ocluke » Sat Oct 06, 2012 12:09 pm

Is it possible that Ramp Setpoint Mode does not work when the output selected is hysteresis controlled? The wiki states:
"Ramp Mode works by overriding the temperature setpoint for a given output controlled Differentially or by PID"
http://www.embeddedcc.com/wiki/index.ph ... point_Mode

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JonW
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Re: Ramp Setpoint Mode not working

Post by JonW » Sat Oct 06, 2012 12:18 pm

The Wiki is outdated. The term "Differential" is no longer used and it is referred to as "Hysteresis".

ocluke
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Re: Ramp Setpoint Mode not working

Post by ocluke » Mon Oct 08, 2012 11:10 am

JonW wrote:The Wiki is outdated. The term "Differential" is no longer used and it is referred to as "Hysteresis".
I assumed so, but I can't find another point of failure in the programming that could be the problem.

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Re: Ramp Setpoint Mode not working

Post by ECC » Thu Oct 11, 2012 10:08 pm

Hi ocluke. It sounds like you are doing everything right, everything that you describe is correct. Note that the setpoint that you enter in the Current State Properties table, 65 in your case, is immediately overwritten by the new ramp setpoint when in ramp mode. Things to try:
  1. Temperature probe association. Make sure that you are ramping the setpoint that is associated with your output! Make sure Alt Pid is disabled if you are not using it for this state as it could switch the association.
  2. Latest firmware revision? v3.3 had a bug on the upper temperature probes (462 only) http://www.embeddedcc.com/wiki/index.ph ... and_Errata
  3. The output needs to be set in either Hysteresis or PID control, these are the only two control modes that use a temperature association.
  4. This might be a case of output contention. By that I mean multiple processes trying to control the same output. Make sure that no other processes controlling this output are enabled, including manual mode.
I would recommend using the datalog feature. You can plot the temperature setpoint along with the temperature. You should see (when you enable the process) the temperature setpoint immediately goes to the start temp (which you noted that you observed), and it then slowly ramps down to the End Temp over the ramp time. Obviously this is going to be pretty slow over a 24 hour period, you may want to shorten the ramp time just to see how it works and get a feel for it.

This doesn't sound like your situation, but I'll list it here anyway.. Remember, we are ramping the temperature setpoint, not the temperature. If everything is setup correctly, the temperature should follow the setpoint when it is adjusted. But if the cooler can't keep up for whatever reason, the temperature may not be able to follow the setpoint due to system design.

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Re: Ramp Setpoint Mode not working

Post by ocluke » Thu Nov 29, 2012 7:29 pm

ECC wrote:
  1. Temperature probe association. Make sure that you are ramping the setpoint that is associated with your output! Make sure Alt Pid is disabled if you are not using it for this state as it could switch the association.
  2. Latest firmware revision? v3.3 had a bug on the upper temperature probes (462 only) http://www.embeddedcc.com/wiki/index.ph ... and_Errata
  3. The output needs to be set in either Hysteresis or PID control, these are the only two control modes that use a temperature association.
  4. This might be a case of output contention. By that I mean multiple processes trying to control the same output. Make sure that no other processes controlling this output are enabled, including manual mode.
I would recommend using the datalog feature. You can plot the temperature setpoint along with the temperature. You should see (when you enable the process) the temperature setpoint immediately goes to the start temp (which you noted that you observed), and it then slowly ramps down to the End Temp over the ramp time. Obviously this is going to be pretty slow over a 24 hour period, you may want to shorten the ramp time just to see how it works and get a feel for it.

This doesn't sound like your situation, but I'll list it here anyway.. Remember, we are ramping the temperature setpoint, not the temperature. If everything is setup correctly, the temperature should follow the setpoint when it is adjusted. But if the cooler can't keep up for whatever reason, the temperature may not be able to follow the setpoint due to system design.
  1. I'm not quite sure what you mean here. I'm ramping Output 5, which is the same output used in this state of this process. Output 5 is my "Fermentor Fridge." Temp probe 7 is associated with that output. The output is set to hysteresis 65. When I ramp, I select Output 5 as the output to ramp. Alt Pid is not enabled.
  2. Current firmware version is BCS-462 v3.4.5
  3. The output is set to hysteresis.
  4. I have no other processes that use this output, including manual mode. Other states in this process use this output, but I doubt that would be an issue as I can only be in one state at a time.

    I've used the data log feature to check the temp setpoint. It does the same thing every time. It immediately changes the setpoint to whatever I set the starting ramp temp to be, and then it never changes from there. I've tried playing with it to ramp 30 degrees in an hour just to see if it drops a setpoint degree every 2 minutes. It never moves past the starting temp setpoint. See below (ignore the 55° and 67° setpoint prior to changing it to 66° hyseteresis with a 66° starting ramp temp). I have it set to ramp 30 degrees in 1 hour. As you can see, it never moves.
    Image
    Are there any other options to troubleshoot?

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Re: Ramp Setpoint Mode not working

Post by battleaxebrews » Wed Jan 08, 2014 9:40 pm

Hi ocluke, were you able to get this sorted? I am having the same problem, with the only difference that I am trying to ramp up (from 50 to 64) over 72 hours. But it has been cycling my fermenter on/off to hold the temp at 50 for over 48 hours now. I'm running firmware 3.7.0, if that matters.

Any help/tips would be appreciated.

Cheers,

Matthew

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Re: Ramp Setpoint Mode not working

Post by Winger22 » Thu Jan 09, 2014 8:57 am

ocluke,

In system settings, under PID and Hysteresis Output Control Settings, have you set the associated output to cool instead of the default heat setting?

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Re: Ramp Setpoint Mode not working

Post by battleaxebrews » Thu Mar 27, 2014 1:30 pm

I'm still not able to get this to work. It is very frustrating because everything else I've tried to do with my BCS works just great. But ramp mode seems completely broken.

Winger22, yes, I have set the output that controls my fermenter (freezer) to cool. Again, I am trying to ramp up the temp for a diacetyl rest. The expected behavior is that my freezer should be turning on less often so that the temp gradually climbs from 50 to 64 over 72 hours. But no matter how many times I've tried this (with various different settings), it just cycles the freezer on/off to maintain the initial temp (in this case 50F). Very frustrating.

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Re: Ramp Setpoint Mode not working

Post by brahn » Thu Mar 27, 2014 4:41 pm

If you turn on the LED style displays you can see the setpoint. That should be updated to the new setpoint as the ramping occurs. Can you see if that's happening?

I tried it on the demo system, and it seems to be working at least as far as updating the setpoint.

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