Addon Instruction Problem

I'm running an AOI on a CompactLogix L33ER.

In the AOI I trigger a TON (Local Tag) with a input parameter bit (HMI Enable Pushbutton). I have a coil (Output Parameter) that is branched around the TON. The coil is energized if the TON is not done.

However, this doesn't work. After troubleshooting the logic, it appears as if the TON (which has a preset of 3600000) is instantly done and therefore my Coil never gets energized (because it is only energized if the TON is not done). If I remove the XIO the Coil does energize but the TON does not time.

This is really simple logic. Is there some reason a CompactLogix cannot do a TON in an AOI? Does anybody see anything obvious that I'm missing (usually at this point I have a 'duh' moment)?

Thanks for any direction! I can't find anywhere in Rockwells 'support' that says this shouldn't work and I've done this logic only a million times over the years (although maybe not in an AOI).

You should be able to make this work. How are you calling your AOI? It sounds as if you might be one shotting the call of the AOI. In which case your AOI logic would only be scanned once and if the Timer DN bit was already set, you would never see your OTE go high since the timer is never updated after the initial scan.

The AOI is called constantly. I can remove the XIO (TON.DN) and the Output is energized. It's only the TON that is not functioning correctly.

This AOI has many other rungs to it that function completely.

Is it possible that your TIMER.DN bit is already set when you the HMI_Bypass is pressed? So Bypass never gets latched in?

The TON ACC has a value of 0. So, it is not timing. However, it does act like it is 'DN' because when I remove it from the OTE the OTE will energize.

It's like the TON is done but it never counted or will count.

If the input bit from the HMI is held ON does the timer time? If not then something in your logic is resetting it constantly. Only a complete post of your program will allow quick troubleshooting.

Here is the AOI. It does act as if something is turning it off but I don't see what could be doing it.

Not to sound redundant - but if I remove the TON.DN bit from before the coil the OTE will energize at that point. The TON will still not time up though.

Bernie - The timer will not time in any situation (I have a Numeric Display on the HMI that shows it always at 0).

Is it possible that the tag HMI_Bypass_Reset is continually ON? The tag is marked with 'Visible' turned off. It may not be apparent.

No sir. Attached is a screenshot of the live values. You'll see it's a 0. Plus, even if HMI_Bypass_Reset was energized the ACC of the TON wouldn't increase but the TON.DN shouldn't be a 1 correct?

The rung with that bit is only setting the accumulator to zero. That doesn't directly affect other bits. Place a -(L)- bit in parallel to the MOV of zero to the accumulator to show whether the MOV has been activated. Is it possible the 'HMI_Bypass_Reset' is turned on just before calling the AOI but turned off after? You wouldn't see it as true on your screen. Do a search for all occurrences of that tag in your program.

In your original screenshot the .DN bit is not turned on. I don't know if that's relevant though.

The AOI is called always. It's always active. My point about the HMI_Bypass_Reset is that it would just be setting the .ACC to 0. This wouldn't cause the TON to be .DN preventing the Output OTE from being energized.

Can you do another screenshot of the live values while 'HMI_Bypass' is being held ON?

Here it is. You'll notice the Bypass OTE is not energized nor is the TON timing.

Well, sorry, you can't see the Bypass OTE nor the TON because they are local tags (not displayed in the AOI Configuration Dialog. But, you can see the HMI_Bypassed is a 0 which is branched around the Bypass OTE so we know it's not set.