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3216 remote ramp configurations

Hello!

I am working with a Carbolite furnace that has installed an Eurotherm 3216 (A2.62 firmware) temperature programmer.

The 3216 by itself allows the user to configure up to 8 ramps in one run, and I want to remotely control the system with a custom LabView program using the provided libraries.

Here's my questions:

1) Does my 3216 allow me to use LabView to create a software that overrides the 8 ramp limit and let the user program a sequence of temperatures made of more than 8 ramps? Or is it limited to those 8 because of the firmware? My idea would be to ignore the 8 ramp pre-configured registers and let the user select different set points and time to get to them (configure unlimited ramps, basically).

2) If the answer for the above is affirmative, what would be the sequence of registers that I need to write? I would like the user to select the target setpoint (in oC) and the oC/min. of the ramp.

I am trying the following but it doesn't seem to work:

- Register 321 (TM.RES): set to Mins:Secs (1)
- Register 531 (RAMP UNITS): set to Ramp per Minute (0)
- Register 276 (L-R): set to YES (1)
- Register 26 (Rm.SP): set to the desired temperature (oC) according to the user's setpoint
- Register 35 (SP.RAT): set according to user's oC/min.

What am I doing wrong?

3) What's the difference between Target Setpoint, Setpoint 1 and Setpoint 2? Which one am I writing when I write register number 26? Which one should I use for a custom ramp configuration like the one I want to do?

I hope I'm not asking too much, but I'm a bit lost regarding how should I configure this.

Thanks a lot in advance for your help!

Best regards,

Mikel
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    Hello Mikel,

    The 3216 can only support a single 8 segment program. This is not adjustable and limited by the firmware.
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    • Hello Mikel,

      You say that you understood how to do in the middle of your message. Would you like to share a sample code so that I can see the structure of a program running a eurotherm (I'm working with 2604, registry addresses are not the same, of course, but the architecture that you should be able to work for me too).
      Thank you very much,

      Have a good day

      Edouard
    • Dear Edouard,

      apologies for my late response. I kinda remember reading your question when you posted it (I got a notification email about it) but for some reason I never answered! Sorry for that.

      Maybe you have already figured out how to operate your controller, however, let me leave some notes here regarding my original post:

      - We never really got the ramp function to work as expected when operating the tool from the LabVIEW VI. When I said (in a previous response) that I had figured out how to set that correctly, it was probably something I believed at that point for reasons that I don't remember.

      - However, we never really needed to use the ramp from the VI, or at least wasn't mandatory for our work, so I never paid additional attention to it.

      - Now I have a colleague who wants to operate with this ramp function, and we together are trying to get it to work. Right now I am trying to re-code the VI according to the help that is provided in this other post: https://c.getsatisfaction.com/eurotherm/topics/eurotherm-3216-ramp-rate-issue I hope we success! Otherwise, we will need to stick to using the ramp function by operating it directly on th controller (no LabVIEW involved), with its 8 ramp limit and so on....

      I hope everything's fine on your side, and good luck.

      Best regards

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  • Bob Anderson (Technical Support Engineer) April 11, 2014 15:52
    Hello Mikel,

    If you require to use different target setpoints it is advisable to re-auto-tune at you new target.
    When the temperatures are fairly close you may not see a difference but in your case you have 500oC so it would be best.

    Note: 3216 only has one set of PID values although you could store this in a recipe and swap recipes when using two different targets.
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  • Going from memory here... was there a limited number of setpoint "writes" you could perform on a 3216?
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  • it is 100,000 write operations of a changed value (in fact the actual limit is likely to be between 2 and 4x because of the way the instrument handles the eeprom).

    However by putting the instrument into "remote" setpoint mode and writing either to the remote setpoint at Modbus address 26 or the target setpoint (I think at address 1 but check documentation), the eeprom is not written to and you can write as often as you like.

    The difference between remote and target setpoints is that if writes are not regularly received to the remote setpoint, about 1 per second, the instrument will signal an alarm and time out back to SP1. The target setpoint has no such timeout, which is usually more convenient unless your comms is writing continuously.
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  • Tim explained the number of write operations very well.

    If you are using the Eurotherm Labview driver vis there is a note regarding this in the 3200 Labview driver Configure Setpoint.vi
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