message display for a pv +

Hello,
I have a message display that i would like to display messages in on a panelview +. I have many messages that i would like to display in this message display. It is also true that some of the messages that i would like to display would be true at the same time. so therefore i would like to display one message for a set amount of time then go right to the next true message. I am having a hard time in figuring out how to do this. Can anyone help me with this.

There are may ways to do this. Myself I would set up a timer. Like a 2 second free running. The done bit of the timer would make true a [FSC] File search and compare instruction. I would compare 2 files. One would be the alarm bits and the other would be a file the same size with all zeros. When a alarm occurs the [FSC] instruction would set the [FD] found bit and report the .POS position of the mismatch. No mater how many alarms you have they would be sequentialy reported every 2 seconds.

Now if your using a contrologix PLC there are complete alarm supervisor logic that would be much better. so hopefully that will give you an idea where to start.

ok i will look into doing that. With this will i be able to display one message at a time and then after set amount of time be able to display the next one that is true until they are all done. then reset and scan them again?
I am not familiar with this instruction. I have never used it before. do you have any examples of this instruction. Also i have to load a trigger value in so the proper value will display the proper message. If you have an example of this instruction that would be great.

Here's a piece of code that I used some time ago to perform a similar function. Hope it helps at least nudge you in the right direction.

It's written in RSLogix 5000 by the way.

Another example with no fancy instructions, handles 250 messages, and the display changes every 3 seconds.

It is a zipped RSLogix500 file...

thanks these help out a lot. I am actually using RSLogix 500!!! and I am defiantly going to use this.
Thanks so much.

bobwithdana said:

There are may ways to do this. Myself I would set up a timer. Like a 2 second free running. The done bit of the timer would make true a [FSC] File search and compare instruction. I would compare 2 files. One would be the alarm bits and the other would be a file the same size with all zeros. When a alarm occurs the [FSC] instruction would set the [FD] found bit and report the .POS position of the mismatch. No mater how many alarms you have they would be sequentialy reported every 2 seconds.

Click to expand...

The instruction to use is FBC (File Bit Compare) - see MartB's reply.
The FBC instruction is available on the SLC and would save a lot of typing compared to Okie's "brute force" method.

Gerry is right. The code I posted was excised from an existing machine (I did not write it, but have added a couple of alarms). If I were to start from scratch, I would use the FBC too.

Paul

Well, I found some errors in the alarm logic for my machine which required quite a bit of work, so in the process, I rewrote the logic using the FBC instruction.

I had to add a whole file for the compare (B20, 30 words), and add some control registers (R6:2 and R6:3), but the logic is much shorter and sweeter.

I also had to fix all the values in the message display to match my bit addresses, since the original code had many skipped ones, and about two dozen that were "out of whack" which was what got me started in the first place.

The FBC finds the mismatch, and stores the result in N15:10. I add "1" to the value before sending it on to the Panelview, since the message display uses a value of zero for a blank message (no alarms).



On a side note, this little SLC did not like having 200-some odd rungs deleted and testing...it caused a watchdog timeout, making my average scan time jump to around 890ms! I never had that problem with a PLC5 ?!?!?. Good thing we are not running production today.