Variable Speed

Discussion in 'Programmer's Corner' started by sparkieni, Dec 8, 2012.

  1. sparkieni

    Thread Starter New Member

    Dec 7, 2012
    I have been asked the following question in my course to do as an exercise. It's based on an Omron PLC and I'm useing syswin as this is what the course is based on.

    Will we use 2 pb wired to 0.00 (speed up) 0.01 (speed down).
    Servo is wired an analogue card & gets its refrence from DM100.
    Value 0000 in DM100 motor stop, value 9999 motor rotates at max speed.
    I have to design a program for fine control, 1 push cause's value to change by 1 up or down.

    The problem is I also have to include a medium control, so for example if I hold the pb for 3 seconds the plc changes the speed by approx 100rpm.
    And then course control so if i hold the PB for say 15seconds it would ramp the speed from 0 to several hundred RPM.

    I have attached what i have done so far and would like some advice on if this would work for the 1st 2 parts, and of course any opinions on how I would add the course control, is it just as simple as adding a 15second timer and an INC DEC to each pb again as I have for the medium control?


  2. panic mode

    Senior Member

    Oct 10, 2011
    get rid of the last two rungs and add command button interlocks so drive can only go in one direction if not already running in the other direction (or try to press both in your example and see what happens).

    place NC contacts of TIM1 right after NO contact 0.00 (1SpdUp)
    place NC contacts of TIM2 right after NO contact 0.01 (1SpdDwn)

    this will give another pulse (increment/decrement) every 3sec if button is held

    to change rate, change timer preset. you should also handle range limits (and prevent overflows).