Master control relay

Does anyone know if you can reset a counter with the reset inside the boundaries of a master control relay, if the MCR is de-energized, leaving the associated rungs without control logic? This s a project I'm doing for school, and my instructor was not vailable when I needed an answer to this question. If you feel like calling, give me a buzz. 708.758.1299
Thanks,
Willie J:beer:

Ummmm.... We'd probably need to know which brand of plc you're using to give a firm answer. Let us know, and we'll take a stab at answering the question.

It is a A/B PLC 5, not sure which serial #.

Let's see if I understand correctly....
You have a counter which is outside(or inside) of the mcr zone....
And a res instruction inside the mcr zone.....
And you want to know if you toggle the reset command when the mcr is disabled, will the counter will still reset?


If I'm understanding the question correctly, the answer is no. When the mcr is deactivated, the res instruction will not reset the associated counter until the mcr is activated.

Here is a picture of what I'm talking about, from a running processor...

what s the spec of the mcr im planning to buy one?

This is a seven year old thread and not related to your question. You should start a new thread. The MCR in this case is a software instruction inside an AB PLC. It isn't a physical master control relay. What is your application and what are your questions?