Timers

[rich]

Hi,

I'm have started using unitronics plcs, and am relatively new to plc programming. On an application i'm currently working on, i am using a number of run/pause timer applications to run a number of pump sets. Is there a way of setting a minimun time setting for a timer so as to avoid for example two timers (run and pause timers) being set at zero, thus causing rapid switching of outputs. Most of the applications in the project involve the run sequences from 3 to 20 minutes and the pause to be2 to 10 minutes, so if i could set both timers for a minimun of say 1 minute. I'm am using a V350-35-T2 unit, the operaters change the timers settings via the touch screen keypad.

Regards,

Rich.

[Simon]

If you enter a timer value in the box as below that will be the default value of the timer. This value will be loaded when the program is first downloaded to the PLC, but can be changed by the user through the keypad entry you have set up. Thje PLC will revert to the default value only if the battery goes flat or you "initialise" the PLC (this can be done via Visilogic or the info screen).

Don't tick the box to the left, with the power plug icon, or that will force the PLC to take on this value every time it powers up.

[rich]

Thank you for your reply, what i'm trying to avoid is the operator setting the time to zero when using the keypad entry, can this be achieved, by say having a minimun setting?

[Gabriel Franco]

You can use "load timer/counter preset" and "Store timer/counter preset" functions to do that.

[Walkerok]

Yes this is able to be done.

You use the store function blocks to "load timer/ counter preset" preset value value as a ML then you can compare the double word to your minimum time you want. If the value of the doubleword is less than or equal to the minimum number you have set then direct store the minimum value into the ML and then "store counter/timer preset from your ML" into your timer.

So whever your customer enters a value less than your minimum you will compare and see that it is less and then rewrite the entered value with the minimum value you will allow on that particular timer.

Keith