reset instruction for RTO

Can a reset instruction be in the rung preceding the TOF, following the TOF or anywhere inthe program?
Thanks guys.

It can be anywhere you want to put it.

Just be aware how instructions referencing the TOF will execute based on when the RES is scanned.

Would that be the same for an off delay timer(TOF)?

I hope I'm not spoiling the lesson ...

Greetings josesaucedo ...



not sure what you’re trying to accomplish - but you might want to take a look at this warning from page 2-8 of the PLC-5 Instruction Set Reference Manual ... (click the link to reach the manual for more details) ...








if this is a “real” industrial process (and not “just” a training exercise) then I strongly suggest that you fully investigate what will happen to the TOF whenever the PLC processor goes through an on/off/on power cycle ... pay particular attention to situations where the TOF is (a) already finished, (b) part way through a cycle, (c) the input to the TOF is off, (d) the input to the TOF is on, (e) and every conceivable combination of all of the above ...



depending on how you’re using the TOF in your program, sometimes there are “gotcha” operations which can lead to some serious safety implications ...



the more I think about it, even (especially?) if this IS “just” a training exercise, then you definitely should go through the same on/off/on power cycle scenarios anyway ... after all, since it’s “training” that implies that you’re trying to learn about the TOF - right? ...



secret handshake: the TOF is often not quite as simple as most people think it is - particularly when the processor first goes into the Run mode (as it does after an on/off/on power cycle) ...



also ... I sent you a PM the other day and never got a response ... did you read it? ... I didn’t keep a copy and I can’t really remember exactly what it was about ... but ... I THINK that it was an offer to give you some “phone call” help with a “forcing” problem that you were having ... let me know if you still need the help ... as I said in the PM, my boss will not allow me to “help by email” as you originally requested - but a phone call session can usually be arranged ... anyway, I think that I adequately answered your question with my final post to that other thread ... at least I tried ...



finally: I hope this helps ... but I've got a hunch that your instructor was really expecting you to research the "book" on the TOF and find that "warning" for yourself ... if so, I apologize to your instructor ... please have him/her contact me sometimes ... I have an offer (a free one) that might be VERY interesting ...



PS Edit ... I just noticed that the title to your original post mentions a reset for an RTO ... but when you got into the text of the posts, you only mentioned a TOF ... what's that all about? ... are we just making a simple problem more complicated than it needs to be? ...