Allen Bradley Micro timer problem

[Swinney]

I am using an Allen-Bradley Analog Micro controller for self-cleaning filters. It has an ingenious program that steps to a higher diferential pressure if the cleaning is unsuccessful and steps back when the cleaning is successful. This part works very well. The problem I am having is with a 24hr timer which is built with T4 timers and counters. Instead of self-cleaning every 24hrs it self-cleans every 48 hours. I would be glad to send someone a ladder diagram if they think they can decipher the problem.

Swinney

 

[FordPrefect]

I'm always up for a challnge.
pankau42@yahoo.com

 

[lrob]

If you haven't had a response , I would be happy to have a look. Is the language RSlogix500? That is the only version I have.
lsrcrr@bellsouth.net

 

[Electromechanical30]

I'd be happy to look at your program.
send to automation_mann at yahoo.

I created a similar program that refers to the status files in the processor. The S2:40 file contains the hour and the S2:41 file contains the minute. Using a GEQ compare instruction, I latch a bit for the start time. I then used an EQU instruction to unlatch that bit to cease the cleaning mode. I can provide an example... Works great, the only problem... the processor time does run behind real time, so I usually loose 5 minutes a month... I have an update function coded in my HMI program to fix that.

 

[sdb830]

The problem with micrologix is you need to purchase an RTC module to use the status registers for time. You can use the timers to schedule time based events but with the RTC module you can schedule by the time of day. Also check the time base for the timers they can be 1 sec, .01 sec or .001 sec. If you havent had any luck getting it fixed I would be glad to look at it sbell@rochacontrols.com