timer inversion

porkchop0025 · Mar 7, 2014

does anyone know how to make a timer count up?

harryting · Mar 7, 2014

You say "please".

Operaghost · Mar 7, 2014

Isn't that what a timer does? Starts at 0, then 1, then 2. Isn't that counting up?

OG

James Mcquade · Mar 7, 2014

what is your application and plc you are using.

when you energize a timer, the accumulation value increases.

regards,
james

Tom Jenkins · Mar 7, 2014

porkchop0025 said:
does anyone know how to make a timer count up?

Why would you need that?

Are you looking for an "off timer" rather than an "on timer"? Most PLCs have that function available.

Are you trying to display the time remaining? Subtract the the accumulated time from the preset.

bernie_carlton · Mar 7, 2014

Some systems have timers which 'reset' the accumulator to the 'preset' value then progress downward toward zero.

porkchop0025 - please specify your exact system.

TConnolly · Mar 7, 2014

Welcome to the forum.

If you are in Emporia Virginia then we can help you.
But if you are in Emporia Kansas then it depends on if you are an ESU student or fan or not because we don't like hornets and Corky is a pansy.

Just kidding.

As others have said it depends a lot on which PLC you are using. There are hundreds of brands and each has its own instruction set. But if you'll tell us the brand and model if possible and also what programming software package you are using then there is a very good chance that someone here will know how to answer your question, there are a lot of experts on this forum.

Joe_Jansen · Mar 10, 2014

If you have a system that counts down rather than up, the easiest way to get an up-counting value is to throw a math block at it as follows:

Upcounter = PresetValue - AccumulatedValue

As Accumulated counts down toward zero, Upcounter will increase, giving you an increasing number that you can display as "Elapsed Time" or whatever you choose.

--Joe

porkchop0025 · Mar 10, 2014

I am trying to make a timer countdown on a factory talk screen

Mickey · Mar 10, 2014

porkchop0025 said:
I am trying to make a timer countdown on a factory talk screen

Timers don't count down. If you want to view a value counting down then do as Tom Jenkins said, subtract the accumulated value from the preset value. Do this math in the PLC then display the results on your HMI.

bernie_carlton · Mar 10, 2014

What type PLC is the FactoryTalk HMI connected to? The AB products timers accumulators naturally count up. If it is an AB then to show a countdown on the HMI then perform the math Joe_Jansen and Tom_Jenkens suggested.

TConnolly · Mar 10, 2014

Since you still haven't told which PLC you are using I'm going to assume that you using an Allen Bradley PLC. The problem is you still haven't told us which model of PLC, and yes, that matters. The quality of the answer you get is directly proportional to the quality of the information you provide about the system you are working with.

However, in general if you subtract T4:0.ACC from T4:0.PRE then you'll have how much time is remaining. If you display this value on your HMI screen you'll have a timer countdown. You can do this in the PLC or you can do it in the HMI numeric display expression.

timer inversion

porkchop0025

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harryting

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Operaghost

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bernie_carlton

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porkchop0025

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Mickey

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bernie_carlton

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TConnolly

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