Engine Hours for PM Reminders RS5000

I am working on trying to logic to remind us of pm work due on our engines based on engine hours. I thought about it today and can only come up with using LIM, GRT, etc.. The only problem is this will be a pretty large routine. I don't mind doing the work, but if there is cleaner way I would like to use it. I have pm's that will need to be done between x to x hours, only problem the hours vary and the pm list is around 200 items. I can handle the old school way of LIM-OTE, just looking for something cleaner. If I understood the user defined tags a little better, I could use a few rungs for all pm's. (I think)? This may not make sense and I don't have logix on this computer to post a screen shot of what I stared on this afternoon. Any advise would be greatly appreciated.

A little background I am an RS 5 / RS 500 guy, I am decent with the RS 5000.

Why not put your PMs in an array with a timestamp of the last time that the machine was PM'ed and then index through the array comparing the current time to the timestamp of the last PM to find the devices that have a PM coming up?

The nice thing about this approach is that it is scalable, you can keep on adding PMs to the system without having to change your code.

Use a totalizer function block for each engine. Totalizers are easy to set up to accumulate hours. The totalizer block has a preset target where you would enter the time between PMs for the engine. When the time is up, the TargetFlag bit will go high. When the PM is complete, reset the totalizer.

rootboy said:

Why not put your PMs in an array with a timestamp of the last time that the machine was PM'ed and then index through the array comparing the current time to the timestamp of the last PM to find the devices that have a PM coming up?

Click to expand...

Cycling through an array of data like that makes for program code that is hard to read and understand.

Logix-User, If you have V16 or greater, then I would go for an add-on instruction which you devise yourself to accumulate hours.
Then place an instance instruction for each engine.

If you want help on this post back.

I'd do it as rootboy. In structured text it's pretty simple and readable

I don't fully understand how to build the array. Everything I have is ver 15, I will check on this to be sure though. Also, I do not have the function block editor license. Thanks for the replies. I am interested in building the array or the add-on instruction if I have a newer version than I'm thinking I do. The array will scan though a set number of similar tags right?

Yes, it make perfect sense, I just haven't built anything like it before. I will try to see if I can build it and post what I try.

danny.michael said:

Use a totalizer function block for each engine. Totalizers are easy to set up to accumulate hours. The totalizer block has a preset target where you would enter the time between PMs for the engine. When the time is up, the TargetFlag bit will go high. When the PM is complete, reset the totalizer.

Click to expand...

I'll second Danny's suggestion. There is no need to re-invent the wheel here, RSLogix already has an instruction to do exactly what you describe. The TOT is perfect for this application, and best of all its built in, making it super simple. But you need the FB exensions to use it. However, if you want to keep a running hours total then instead of resetting the totalizer just add the maintenance interval to .Target - eg for monthly maintenance .target := .target + 720 hours.

See the link below to another thread for info on how to set TOT up as a time totalizer and using the targets and target flags for maintenance.

http://www.plctalk.net/qanda/showpost.php?p=348694&postcount=7

My Attempt

I finally got a chance to give it a try. Am I on the right track?

Alaric said:

See the link below to another thread for info on how to set TOT up as a time totalizer and using the targets and target flags for maintenance.

http://www.plctalk.net/qanda/showpost.php?p=348694&postcount=7

Click to expand...

I've never used the totalizer instruction myself, could you post an example of it in use please? I looked at your link, but it really made no sense to me.

By any chance would you have this data previously recorded in a Historian? A "report" could be written to publish an update.

One of the troubles with doing this within a PLC is the potential for really getting the times skewed when you download code. You (or someone) would have to remember to manually update the datatables to previous values.