In Today's article I walk you through how to Message data from a MicroLogix 1400 to a MicroLogix 1100 over Ethernet using the MSG instruction.
Note: In this example I have a MicroLogix 1400 at IP Address 192.168.1.66, and a MicroLogix 1100 at IP Address 192.168.1.63. Both have the same subnet address, and are attached to the same network via an Ethernet switch. Each program also had the N7 file expanded to 10 words, and the MicroLogix program has a free running Timer in Rung 0 of Program File 2 as seen below:
Step 8) The final setting I need to fill in on this tab that is the Routing Information File, which for this example I use file RI11:0:
Step 11) Back in Ladder File 2, I place an XIC in front of the MSG instruction. For the XIC instruction's address I use the Done Bit of my existing two second free running Timer. This will trigger the message every two seconds, a slow enough period that I'd be able to see the resulting status of each message attempt before the next message attempt is made:
Note: Since A-B Programmable Controllers have limited buffer space for MSG instructions, it's typically not recommended to have multiple unconditional MSG instructions in your program. Instead, consider interlocking messages or triggering them based on timers, to insure you never overfill your controller's message buffer. Doing so can also eliminate unwanted network traffic that unconditional / continuous Messages can generate.
Step 12) With my program now complete, I download it to my MicroLogix 1400 and run it.
Step 13) Now any value I enter into N7:0, 1, and 2 in the MicroLogix 1400 is messaged to, and shows up in N7:0, 1, and 2 in the MicroLogix 1100 after a short delay:
To watch a video demonstration of the above, check out Episode 44 of The Automation Minute Season 4 below:
If you found this article helpful, please share it with your colleagues on LinkedIn, Facebook, Twitter or Goggle Plus!
And if you know anyone who would benefit from Allen-Bradley PLC, HMI, or SCADA training, please let them know about my affordable courses over at TheAutomation School.
You can also share your own thoughts and opinions on this subject by clicking on the “post a comment or question” link below.
- First Look: MOXA Ethernet Switch, EDS-2005-EL - March 4, 2021
- New “Logix Live™” Online Training Course coming March 16th - March 1, 2021
- PLC Training: Free and Trial Programming Software - February 22, 2021