XD Scale Uploading

Why Controller keeps on asking and uploading the XD scale even when it has done the same before and no online changes have been made after that?

Shoaib

8 Replies

  • If foundation fieldbus, you could have configured an invalid xd scale for the ff function block. The ff online function block will not accept the configured value. When you try and download again the value in config differs from that in the online function block and the download utility believes an online change has been made, it isn't it just didn't accept the configured value in the first place.

    Check what the valid xd scaling for the ff device function block is and set your configured value to match one of those, you shouldn't see the issue again.

    Let us know what you found,

    Regards,

    Neil.

  • In reply to IntuitiveNeil:

    Thanks Neil, But is not FF, it is a simple CHARM thermocouple AI module, with "Direct Independent" linearization and a "Out Scale" of 0-1800 F and a "XDScale" of "-454 - 2501.599854"

    Shoaib

  • In reply to snizami:

    Ok, we've just been through some issues with AI XD/Output scaling with thermocouples and CHARMs on my current project. Those values for XD scaling seem to be very specific.

    What type of CHARM functionality have you configured? e.g. Type J Thermocouple Input CHARM, Uncharacterised Thermocouple Input CHARM etc. I could be wrong but chosing a specific type of Thermocouple pre-determines the XD scale, so it could again be similar to the FF issue, where your configured values don't match the specific type of Thermocouple you have configured and are therefore not accepted during the intitial download.

  • In reply to IntuitiveNeil:

    CHARM is configured as k-type thermocouple, and XD scale values of "-454 to 2501.599854" directly match with the DeltaV provided values in Centigrades, which are "-270 to 1372"

    Shoaib

  • In reply to snizami:

    try exactly -454 to 2501.6 F. It might simply be an issue of the precision you are using in the configuration. The download utility may simply check for exact match. i.e. 2501.599854 is not the same as 2501.6.

    My C to F conversion utility gives 1372C = 2501.6F

    Otherwise I don't know. Sorry.

  • In reply to IntuitiveNeil:

    it's OK, you did your best, thanyou!

    I checked the decimal issue before. It was not causing this issue. I'll wait for someone else to stepin

    Shoaib

  • In reply to snizami:

    I set up a K type TC with a CHARM on Friday but using centigrade. Initially i set XD SCALE to -220 accidentally and got the same XD SCALE upload issue you are reporting when I next downloaded as the system had automatically corrected to -270.

    I suggest you check the setting for XD SCALE of the AI function block from control studio online and set the offline values the same as the system has set for you.

    Mine works, but I accept I didn't use deg F.

  • In reply to IntuitiveNeil:

    Could the XD_SCALE decimal place parameter (AI1$XD_SCALE.DECPT) possibly be contributing to the issue?