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.
Step 1: Simulate a Process and Record the Data
I connected a UDC 3200’s output (a 1-5 VDC voltage drop across a 250 ohm resistor in the output loop) to an analog input on a Honeywell paperless recorder. The recorder was set up to sample at 10Hz and run the fastest chart speed, 6000mm/hr. At that chart speed, the time divisions are marked every 10 seconds and the entire time axis is only a minute and 15 seconds.
The UDC 3200 samples and makes a PID decision six times per second, so a 10x/second sampling rate should pick up any hiccups on the output. The controller’s output was absolutely stable at 13.6%. The chart showed a perfectly straight line.
Step 2: Change the Controller Config
I used an infrared adapter to communicate from PIE software to the IR port on the front of the controller.
I first uploaded the entire configuration and the output’s straight line on the graph didn’t make a twitch.
Next, I made an ‘on-line’ change to write just a new IP address and saw no deviation at all on the output.
Then I downloaded the entire configuration to the UDC and no change occurred at all on the output signal.
Step 3: Report my Findings
What I found was good news. Honeywell PIE software read and write operations do not affect the operation of UDC controllers, even during a running process. Whatever configuration changes are made will be implemented immediately, but the configuration change activities will not alter the performance of the UDC controller.
See the Lesman website for more information on Honeywell UDC family 1/4 DIN universal digital controllers and Process Instrument Explorer software.
