Integer

[akreel]

If it isn't double-coiling, bit shifts, copies, moves, messaging, or latching:

Make sure your computer is still online with the PLC. On a few occasions, I've been mysteriously bumped off without warning. On those occasions, I've seen things like this that just don't make sense.

 

[RoTaTech]

Tony - also check your version of RSLogix.
I had one version - I think it was 4.5 or so - that would show that symptom.

The ladder update would not work properly, unless I opened the data file associated with that output coil, then the ladder would update and show the ON or OFF state properly.

The physical outputs were working; it was an issue with RSL not showing the state.

RT

 

[robert denton]

An MCR instruction can produce the same results.

Here is a copy and paste from rslogix:

MCR

This output instruction (sometimes known as "Zone Control") is used to set up areas or "zones" of your ladder program where all non-retentive outputs may be disabled at the same time for the same length of time. It is used in pairs, one MCR to define the start of the ladder area to be affected and one MCR to define the end of the area.

An input instruction is programmed on the rung of the first MCR to control rung logic continuity. When the rung goes "false" all non-retentive outputs within the controlled zone are disabled. When the rung goes "true" all rungs are scanned according to their normal rung conditions (disregarding the zone control instruction).

This is exactly right. The MCR is a great scan time saver if used right. It can be hard to find, as you must start at the culprit rung, and scan one rung at a time up the ladder. Chances are you'll find it. It is also a good sign that the programmer was up to snuff.

Two or more OTE's with the same address is bad business, and the final instruction determines the status of the output.

 

[tonym]

Robert I think your exactly right. I was reading up on those and I have not had time to look at the program again but I bet thats what it is.

Thanks everybody

 

[JorgeR]

There are times when the OTE becomes true and nothing else on the rung changes.

This program actually works but I don't know how.

tonym,

I'm just wondering, does this output realy come on but is not displayed on you computer screen? If so, it sounds to me like the output might be turning on and back off faster than the rslogix program updates the screen. Just a thought.

Jorge