easy one: Continuous timer for MSG block reads - Logix 500

Hello again. SoI need to read data from another controller every 60 seconds. I put in a TON and I get one read. I want to reset the same timer while triggering the MSG block at end of each cycle.

I know this is easy (not for me). Thanks!!!

use the DN bit from the timer as a XIO to "break" the feed to the timer. If the timer is not DN then it will time out once it times out it removes "power" from itself loosese it's DN bit and we go round again

The self-resetting timer is a very common way to get a "one shot" bit (the .DN bit) that occurs every so many seconds in a PLC program.

When you are using it to trigger a Message instruction, take into consideration how fast you trigger the Message versus the longest timeout value. You don't want to pile Messages into the execution buffer if the remote device is disconnected.

Since you are sending a message at a 60 second interval, you should be OK because the standard DH+/DH485/DF1 message timeout is 5 seconds and on Ethernet it's 23 seconds.

Both, very excellent replies! I used them both. Thanks for the time-out info! I am using Ethernet reads.

Got it working like a champ. Solves a few issues for me.

Many Thanks again!!!

Consider executing the MSG command when data has changed. Takes some memory space and logic, but it can keep un-necessary traffic off of the communications highway.