Hi guys.
I'm working on a logic to control multistage electric heater for an air stream. The heater consist of 10 sections with ON/OFF control and 2 sections with independent proportional control.
I have to write PLC program emulating vernier control.
My first approach was just simply split 100% PID loop output range on 12 and turn ON/OFF discrete sections any time 8% step is made. Rest 2 proportional sections can be controlled in parallel between 8% steps, modulating its output from 0 to 100 within 8% step and resets to 0 after new step made.
My concern is that output temperature will be bumpy due to difference between newly "ON" heater section warming and just turned off "proportional" section cooling.
Just curious if anyone has better ideas for control algorithm or maybe a references/links to useful materials.
I'm working on a logic to control multistage electric heater for an air stream. The heater consist of 10 sections with ON/OFF control and 2 sections with independent proportional control.
I have to write PLC program emulating vernier control.
My first approach was just simply split 100% PID loop output range on 12 and turn ON/OFF discrete sections any time 8% step is made. Rest 2 proportional sections can be controlled in parallel between 8% steps, modulating its output from 0 to 100 within 8% step and resets to 0 after new step made.
My concern is that output temperature will be bumpy due to difference between newly "ON" heater section warming and just turned off "proportional" section cooling.
Just curious if anyone has better ideas for control algorithm or maybe a references/links to useful materials.
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