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  • pulse relay?

    I'm using a DL205 with the DL150-1 CPU and F2-08TRS relay modules. I want to pulse these relays with a one shot like device that triggers on a transition. I've tried using the PD command but the pulse width is too short for the relay to actuate in time due to the short scan time. I'd like a pulse width of around .5sec.

    How should I do this?

    It would really be nice if one could specify how may scan passes would go by before resetting the output.

    Thanks,
    Phil


  • #2
    DL150-1
    What?

    If you actually mean a DL250-1 then just use a timer. A TMRF has a 1/100 second time base. A preset of 50 will give you really close to .5 seconds. Number of scans is a very unreliable base for measurement of time.
    thePLCguy

    Bernie

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    • #3
      Originally posted by bcarlton View Post
      What?

      If you actually mean a DL250-1 then just use a timer. A TMRF has a 1/100 second time base. A preset of 50 will give you really close to .5 seconds. Number of scans is a very unreliable base for measurement of time.
      Thanks bcarlton,
      You are right the CPU is a DL250-1. I tried setting up a TMR to count enough ticks for a .5 sec output using greater than and less that contacts. That seems to work fine but the timer keeps on running (as long as the input is true). The input can remian true for long periods of time. I don't know if it will rollover again and emit another pulse. Do TMRs keep going after they reach 999.9 sec or do they halt?

      Comment



      • #4
        Try this as a template

        PLC 250(-1)

        // Rung 1
        // Address 0
        #BEGIN COMMENT
        "After C0 (Input conditions) turn true timer T0 iand C3 are turned on for 1/2 second. C0 will "
        "have to turn off and back on sometime after the timeout of T0 to re-initiate the cycle. "
        #END
        STR C0
        PD C1

        // Rung 2
        // Address 2
        STR C1
        STR C3
        ANDN T0
        ORSTR
        TMRF T0 K50
        OUT C3

        // Rung 3
        // Address 10
        END

        // Rung 4
        // Address 11
        NOP


        #BEGIN ELEMENT_DOC
        "C0","Condition","","Represents the set of conditions to initiate the output"
        "C1","One shot","",""
        "C3","Output","","Represents the chosen output"
        "T0","1/2 Sec Timer","",""

        #END
        thePLCguy

        Bernie

        Comment



        • #5
          Originally posted by fyl View Post
          Do TMRs keep going after they reach 999.9 sec or do they halt?
          They halt at 999.9 (or 99.99 for a TMRF).

          Brian

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