MRPLC82

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Posts posted by MRPLC82


  1. Evening,

    I struggle with simple task...

    I need to activate PLC Output at the specific time of a day.

    I`m using GSV to obtain PLC time, data is being moved to DIN[7] registers.

    Then I have three EQU (Hour / Minute / Second) and at the end of rung there is OTL for output.

    Rung below I have two EQU (Hour / Minute) to disable output at different time - OTU.

    However every time OTL is energised , OTU on rung below is fired too.

    What am I doing wrong here ?


  2. I need some advice how to tune PID properly.

    The PID is only PI type (two mode) and its overshooting frequently. Assuming I need to tune P with starting incrementing by very small steps till PID oscillates. 

    Once the P is established then will be tuning I , again with small increments till PV follows SP. 

    So this is my assumption below but would like someone to comment on it as I haven’t had to do it before , been learning PLC for 4 months now. 

    Do I need to start a machine and then start tuning PID or can this be done in more friendly way , offline ?