Posts Tagged Honeywell controllers
In order to understand level readings, you must first comprehend how the instrument works. Three of the most common level-measuring techniques involve using a displacer, float, or differential pressure instrument.
Here’s the catch.
While each of these instruments can be used to report a level reading, none of them actually measure level.
I know what you’re thinking…
If none of these instruments measure level, how do we end up with a level reading? Read the rest of this entry »
You’ve heard this phrase before: “It’s simple. But nobody said it would be easy.”
And this is exactly one of those cases.
The Honeywell UDC3500 digital controller can support up to four setpoint programs, the ramp/soak profiles used in batch control operations. But after configuring all four profiles, I was stuck on how to select the one I wanted the controller to use.
There’s no “Program Select” button on the keypad. So I was mystified on how I was going to select my setpoint profile program #3.
Industry statistics reveal that a fair percentage of control loops are controlled manually, and are not automated. This fact was brought home last week, when a caller told us he needed “something to adjust the valve position so that the valve stays where it’s been set. And it’s real important that it can’t accidentally go off its own”.
What he was describing is what we call a manual station. It’s a controller where the 4-20mA current output stays fixed where it is until someone pushes buttons on on the front of the controller: up to manually raise the output value, and down to manually lower it. Typically, the output value is displayed for the operator as a digital number from 0 to 100 percent.
So what’s available to fill the bill?
Read the rest of this entry »
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.