MSG instruction

I have been using MSG to turn on an outputs between MicroLogix 1100 plc's.
My concern is that the MSG instruction seems to run on every scan here for an alert that's going to be true once a year.
I was wondering if there is a way to get an acknowledgement back from the target that it got the message successfully and so I can stop sending it until when I need it again. This would let me cut down on the amount of messages sent across my network which may be important as I start using them more. I read page 355-356 in 1763-RM001 and Its unclear to me when they say "the DN bit is set when message is transmitted successfully" Do they mean it just got sent or they know it was received?
I was going to write more alarms or alerts to N7:13 and sending them through to the Office doser control PLC with the same MSG.
I am open to suggestions of a better way to do this.

In general, in AB parlance, a MSG .DN bit will only get set once the message handshake is received that the message (Read or Write), was 100% successful.

It is intended that the .DN bit is used as a total success indicator.

However, looking at your rungs of code, there is nothing to trigger the message again. A MSG instruction requires that the rung goes from False-to-True to be triggered. You need to put a conditional on the rung to make it transition from false to true, either on a timed basis, or state change.

I notice the rung is in edit, can you post the final version?

I thought the DN bit on rung 62 was unlatching the EN bit of MG9:0
Thats why I thought it was rerunning the MSG every scan. I am reposting the program.

The must be some condition under which you want to send the message or do you want to send it continuously?

We see that this unit (IP 10.1.1.173) is to send the contents of N7:13 to N7:6 in a unit which is at IP 10.1.1.101. N7:13 only shows up in the two rungs above.

Is it possible you want to send the contents of N7:13 whenever it changes (switch from Auto to Manual)? Do you want to re-attempt the sending if there is an error? Just let us know.

I want to send N7:13 whenever the system is switched to manual override. In Manual this system will no longer automatically switch over from an empty tank to a full one. So someone has to go look at them once a day. So in addition to the panelview screen warning in the control room they want a sounder to go off for a few seconds every hour until it is switched back to auto and N7:13 sends a 0 to N7:6 in unit at IP 10.1.1.101. This is to prevent the system being left in manual for several days after a repair or maintenance.
Yes I would like to resend if there is an error

Here is the modified program.

Edit - you didn't say it but I'm going to assume that you would like the '0' in N7:13 written by the message if a switch is made back to auto.

Very ingenious Bernie. Thank you. Its a better solution than the one that my RA-techconnect took a week to get back to me with. Now I want to MSG other conditions to the same PLC to turn on some outputs. I added 2 more MOV instructions writing a 2 and a 4 to N7:13 and added some rungs to the target PLC. Do you think this is the best way to do that or should I send separate MSG's for each.

:site:

Much like you are treating individual bits in the received word I am giving an example of the modified program but controlling each individual bit in N7:13. That way you can notify the receiving PLC of up to 16 individual conditions (in any combination). If any of the conditions changes then N7:13 has a different value and triggers the MSG.

Yes your right. I tested my way and N7:13 overwrote all the bits at the target with the value sent of just one bit. Your way I am setting the value at the sending PLC to include any combination of the 16 bits. Thanks again Bernie