Timers

How to get a TON timer to count up when the input is low, and also count up when it is high. All on the same timer, I think it can be done woth a MOV function, but how?

Please describe a situation where the timer will NOT count up...

beerchug

-Eric

Lets make sure we understand what you want. You want the counter to count UP each time the input bit makes a transitions. Count up once when it transitions low to high then counts up when it transitions from high to low?

You didnt state what PLC but I will assume AB. I would think that the use of a one shot would allow you to count up on each transition.

I will test this tomorrow when at work.

Is there another condition for your TIMER , neither high nor low, that it is not supposed to be timing? When you say low or high are you referring to a binary input of "0" or "1", or integer numbers such as for example, 1000 or less equals low and 10000 or more equals high?

How much is another timer? You could use one with a N.O. contact and another with a N.C. contact.

????

What you are asking for is basically an unconditional rung, why?



Is this timer a realworld timer or PLC timer?
What is its function?
Without more detail I don't have an answer.

C.S.:

Per your original post, you want INPUT_IS_LOW OR INPUT_IS_HIGH to drive a TON? As others have pointed out, that is essentially an unconditioned timer.

In reading between the lines, what I think you want is a timer that STARTS timing when the input CHANGES to Low, and to RESTART when the CHANGES to High.

If so, check out the RST instruction. You also might want to give the OSR (or ONS) a look-see.

It's just a guess, but are you trying to test for machine movement? Some programmers approach this problem thinking: "If the gear stops with a tooth under the sensor, then I need to run the timer. But also, if the gear stops when it's NOT seeing a tooth, then I need to run the timer for that condition too." This line of reasoning would help explain your original request. [attachment]

As shown above, if you're trying to test for movement, all you need to do is reset the timer each time your sensor sees another tooth roll by. This way it won't really matter whether the machine stops with the sensor ON or OFF a tooth.

Timer

You would be MOV (moving) different values into the timer preset.