Compactlogix Msg instruction; how frequently to trigger?

In the few examples that I have seen on AB's website, the MSG instruction is triggered continuously; as soon as it's done, it is re-triggered. It strikes me that this method would keep the network very busy. I trigger mine once or twice a second to avoid this. Am I worrying about nothing?

Depends how quickly you actually need the information that is transmitted...

I'm with you, I don't like to spam the network if I don't need super fast communications. Also, doing it continuously is inconsistent vs. using a set time delay (I generally use 250ms). So what works now may not work later due to future traffic issues. I like knowing it will work with a conservative delay between messages.

Thanks, rupej. Agreed

Depends entirely on the information that's being messaged...

If you're communicating how many parts the line has run, you can send the message once per second or so. If you're communicating an encoder position for something motion specific, you might need to send the message continuously (or more likely, through produced/consumed tags). If you're communicating a FIFO list to keep track of users who have logged into a protected area on the HMI, you could message it once per minute.

There's flexibility here for a reason, and it's your job as the programmer to determine how much of a delay between the messages being sent is the longest amount of delay possible that will still accomplish your goal.

Another way is to only message when the data that's being exchanged changes.