PLC-5/250: unsolicited messages

An unsolicited message is generated in a PLC-5/250 by programming a Message Instruction. Refer to a PLC-5/250 programming manual for help on how this instruction is programmed. The Message instruction requires several fields to be programmed properly for it to function properly. These fields are as follows:
  • Priority =
    Norm
  • Local/Remote =
    Local
     (data is being sent to a Local processor)
  • Local Link Type =
    DH+
  • Station ID =
    Node #11
     (the station address of the KT card that the message will be sent to)
  • Communication Command =
    Typed Write
     (used to send PLC-5 type data)
  • Internal DT Address =
    0N0:0
     (the source of the data to be written)
  • External DT Address =
    "0N0:0"
     (the destination data table address; the Item that will be used to establish the DDE link)
  • Requested Size =
    10
     (the number of words to be sent)
Valid communication commands are as follows:
Typed Write
 is used to send PLC-5/250 type data to a topic configured as a PLC-5/250. A PLC-5/250 type address must be entered as the External DT address in the message instruction and the same type address used as the item in the DDE request.
PLC-2 Protected Write Word
 is used to send PLC-2 type data to a topic configured as a PLC-2. A PLC-2 type address must be entered as the External DT address in the message instruction and the same type address used as the item in the DDE request.
PLC-3 Protected Write Word
 is used to send PLC-3 type data to a topic configured as a PLC-3. A PLC-3 type address must be entered as the External DT address in the message instruction and the same type address used as the item in the DDE request.
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Normal