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Posts posted by antonk

  1. Bumping this one since I got another question as well.

    I'm trying to establish communication with the V130 trough a ModBus simulator on a PC, often enough I can get a connection but I haven't been able to read or write anything to the PLC. I've tried several softwares and all of them has a field "Slave ID: ". Is this the ID filled in the Modbus config FB? I.e 255?

    Also, have anyone here used some kind of Modbus simulator with a Unitronics PLC they know to be good? Several of the ones I've seen are quite messy.

    I would really appreciate some input, both on this post and the first since I haven't been able to figure that one out either.



  2. Hi all,

    I have a question regarding slave adressing on Modbus.

    We have a V130 which we want to use as a slave on a Scada system. When I read about slave adressing in the help file the pointer value offset is given for each data type, no problems. However, when I read the examples (and also different topics regarding modbus here on the forum) another offset seem to occur. For example when writing a 3-bit vector of outputs starting at O8:

    "SCADA as the Modbus master to color PLC:

    • Convert the HEX address to DEC.
      In the SCADA application, set the Slave: Start of Vector parameter to 46393 (30001 + 16384(4000h) + 8) and the Force: Vector Length parameter to 3, enabling the Master device to write to O 8 - O 10 within the slave Vision controller."

    Where does the 30001 come from? The 4000h is obvious since it's mentioned in the help file.

    A similar offset of 40001 seem to appear when reading/writing MI:s, 400001 for MF:s and so on.

    I must be missing something fundamental since I can't find any information about this offset.

    A couple of words around this would be much appreciated.

    Cheers from Sweden


  3. Hi again,

    Since no one has yet answered, lets put it this way:

    How is the alarm acknowledge function supposed to work? Isn't it just to specify a bit as "Acknowledge bit" and when the cause of the specifik alarm is gone, let this bit go high (i.e. by pressing a button) and then the alarm will be acknowledged?

    In the alarm examples I've seen the acknowledge bit isn't used, so I'm a bit lost.

    regards Anton

  4. Hi,

    I'm having some issues regarding alarm acknowledge on my V130. I have a couple of alarms I would like to be acknowledged by a button connected to an input, the input sets a MB which is choosen in each alarm config as "acknowledge bit". I thought that this would acknowledge the alarm just as the selected MB goes high, but it doesn't work.

    Instead, the "F2" button is the acknowledge button, in the plc-project the "F2" button isn't used anywhere regarding the alarms. Is this maybe some default that isn't possible to change?

    regards Anton

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