Msg time out

I have a ML 1400 Reading messages from 12 other PLC's.I have it set up so if the first message from each PLC gives an ER it will latch a bit and unlatch if that message gets a DN. I use these bits to signal the machine is powered down and PLC is off and I also use it to disabled any remaining messages from that PLC so I can skip over them, It works fine when most machines (PLC's) are powered up, if a few are powered down they show up on my excel sheet. My question is I noticed when I get to more than half the machines off (weekend)
It slows the system down enough that some machines on start to drop in and out, I see the TO bit toggling in the MSG file. All my messages are set at 33 seconds on the TO bit which I guess is default.
Any suggestions or does anyone have a different way of determining if target device is active,

It's best to give some screenshots of your logic. Right now I am thinking setup watchdog timer and use it to disable with MCR zone.

Here are 2 MSG's as you can see B13:0/10 is not latched so the MSG's to DB
are active

In this shot Both machines are powered down (141 &146) so their off bits are latched, They only have one message each, if they had multiple MSG's I would use the latch bits to disable any additional messages until the first message to that machine un latched it

You screenshot is a little bit low on the quality side, plus my laptop is such small & low resolution even at 400% magnifier, makes it difficult for me to look at. But look at the thr first few rungs, you are not really 'skipping' when ER bit is on, you use it to unlatch and therefore reactivate it.

I would suggest do a READ first, if READ.DN and not ER then do a WRITE. You may not even have to daisy chain the logic

how do you insert your screen shot in your reply

When you click the insert Image icon, there is a link, you need to upload to your favorite web site, I use

https://postimages.org/

I put an AFI in front off all my MSG instructions to run tests and found that when 80% or more of my messages were trying to poll a PLC that was off it would affect the messages that were connected to PLC's that were on.
Could this be due to the settings in Channel 1

Message connection time out, I don't see anywhere you can set how many times it retries

I recommend to cascade (sequence) your msg instructions so only one msg is active at time
Step 1 - Trigger Message Read From PLC 1 and wait for DN or ER bit then set Step 2 Step 2 - Trigger Message Read From PLC 2 and wait for DN or ER bit then set Step 3 Step 3 - Trigger Message Read From PLC 3 and wait for DN or ER bit then set Step 4 and so one

tarik1978 said:

I recommend to cascade (sequence) your msg instructions so only one msg is active at time
Step 1 - Trigger Message Read From PLC 1 and wait for DN or ER bit then set Step 2 Step 2 - Trigger Message Read From PLC 2 and wait for DN or ER bit then set Step 3 Step 3 - Trigger Message Read From PLC 3 and wait for DN or ER bit then set Step 4 and so one

Click to expand...

This is exactly what I do with message instruction logic. This also makes it easier to skip messages to devices that are unavailable. You need to come up with a strategy to periodically check to see if those unavailable nodes are back up and available.