Archive for category Ethernet
Why does my Honeywell UDC controller flash UNPLUG at me?
Posted by danstips in Ethernet, Honeywell, Installation, Loop Controllers, Troubleshooting on February 15, 2017

Honeywell UDC UNPLUG Error Message
People will fire up a new UDC 1/4 DIN loop controller, like a UDC2500 or UDC3200, and discover that the lower display periodically flashes an error code: UNPLUG. But what does it mean? Is something wrong?
A search of the pdf version of the manual hints that the Modbus Ethernet communications is involved:
The Ethernet status screen shows the network status of the Ethernet Link. This may be accessed either via Ethernet or via Infrared Communications. For example, if the Ethernet cable is unplugged, then the instrument cannot send up the EUNPLGED diagnostic message via Ethernet.
But the word UNPLUG is nowhere else in the manual.
Digital Communications Toolkit
Posted by danweise in Communications, Ethernet, HART, Modbus, Serial, Service, Troubleshooting on July 17, 2012
We’ve gotten feedback from several people who have asked what I carry around to deal with serial or Ethernet communications issues. So I dumped out my comm tool bag and here’s the list of all the stuff.
Tested and proven: Honeywell PIE software reads and writes do not affect a UDC controller’s output
Posted by danstips in Batch Control, Communications, Configuration, Ethernet, Honeywell, Installation, Loop Controllers, Service, Software on June 28, 2012
A customer has several UDC 3200 loop controllers with newly added Ethernet cards. He needed to configure each of the controllers’ IP addresses using Honeywell Process Instrument Explorer (PIE) software. Because the controllers are working in a 24×7 continuous process, he was concerned about how making those changes would affect each controller’s performance.
So he asked me: Would a PIE action of uploading config files from or downloading them back to a controller affect the controller’s performance?
In the past, I’d only ever changed a controller’s IP address when it was on my workbench, not when it was actively controlling a process. So I’d never paid attention to whether PIE communications would affect the controller’s output or its PID action. Since I couldn’t answer the question, I told the customer I’d run a test to find out for sure.