OptoNews Tip: PID loop with a long dead loop time

Posted by Jean Femia on Sep 28, 2016 4:24:57 PM

PID oscillation illustrationOptoForum member tohox recently posted a question about using PID control loops on a SNAP-PAC-R1 rack-mounted controller.

The issue? A really long dead loop time. 

"The time delta between the moment the strategy opens a given loop's valve [and] starts the pump+furnace and the moment a temperature increase is measured can sometimes be on the order of an hour," tohox notes.

So how can overshoot and oscillations be minimized, or more fundamentally, is a PID loop the best control option in a case like this?

Tohox also asks whether inputs must come from analog I/O in the system, or whether they can come from another source, like floating point variables within a table. 

Take a look at the answers and expand your knowledge about PID loops with this real-world example from the OptoForum

Read the Forum post

Topics: Energy management, Tips, optonews, PACs, I/O, Building management, Modbus, PID loop control, OptoNews 2016-09-28

Written by Jean Femia

Jean Femia writes about technical subjects and has focused on automation and control systems for more than 15 years. She likes learning about technology and taking corners in her Honda S2000.
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