Midnight Reset

Hi, just moved over from commissioning to a role doing some basic level PLC code stuff.

Looking to reset a counter at midnight in an moron C200 using cx programmer. did a little digging and looks like the =DT(341) function is the one to use but wondered if anyone out there can break its operation down for me into novice speak??

Appreciate any advice thats out there.

That is a really old PLC and no longer supported - ready for replacement with a CS1 processor, power supply and rack - I/O can remain.

moron C200

Click to expand...

MORON C200 PLC???

THIS MUST BE THE PLATFORM THEY RUN OUR CORPORATE OFFICE WITH!!!!!

BCS

Tell me about it, as a company there is a plan going forward to replace them with CJ1's but right now and until early next year we're stuck with them.

Any thoughts on the best way to reset this counter??

well spotted BCS, thats what happens you you start trying to type on a weekend after a night out!!

I think our offices must run on the same platform.

I needed the laugh anyway, so thanks for that.

I personally have never used Omron PLC's although the new winch system we are getting will be using Omron, so I had better start looking into it.

Generally speaking though you will need to write a line of code (Ladder) that when it sees the Real Time Clock of your PLC at midnight, a reset output for your counter will become true. I would use a one shot feature for this also so that this will only take place for one scan once a day at midnight.

(I am speaking on Allen Bradley experience and am not 100% sure your PLC has an RTC feature.)

I did a couple of Google searches and it looks like there is a lot of material on the subject and even some youtube vid's showing you how.
I googled "how to reset a counter in C200 omron plc using cx programer."

Also there should be someone strolling by the forum before long that is knowlagable with your platform and can give you better details.

Best of luck.
BCS

Thanks for the info BCS, I'll take a search on google and see what I can find.

enjoy the weekend.

Which model CPU - there were many and some did not have a real time clock? C200h-CPU? or HE or what?

By the way - you put CQM1H on another forum - what is it? They are quite different. Get it right for assistance.

We have a mixture of both across numerous sites, hence the other post with a different PLC type, I was hoping there's one fix for both??

Need all CPU types to determine whether they have a time clock or not - some do - some don't.
Also probably different ways of handling the info as they may be in different registers in different PLCs.

lower model C200H CPU not have internal clock.

or

use external timer clock to trigger.

better upgrade.

Many timer switches are available in the market which is used to control appliances like lights/fans etc. You could use one of this to trigger a relay at midnight, say for one minute. Of course the, relay then tie to a PLC input to do your reset. Timer switches are cheap now, so it may be a temporary solution until you upgrade your PLC

Regards

Here is how I do it in the latest PLCs (CJ, CP, CS series). For other PLCs the time clock hours may be in a different memory location. Note ANDW is used as a mask and the hours have to be preceeded by # in the compare function. You can use a DIFU (rising edge one shot) instead of a straight internal bit if you wish.