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PID controller - control temperature

Created by: Milosh at: 1/9/2014 8:54 PM (7 Replies)

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1/9/2014 8:54 PM	Rate (0)
Milosh Silver Member Joined: 8/16/2010 Last visit: 11/7/2019 Posts: 549 Rating: (6)	Hi all I use TIA V11 and s7-1200... How to control temperature via heaters which will be turn on with solid state relays (digital signal)? And/Or with valve which control flow of hot water? Both need to be controled with PID controler??? I read about PID_Compact (need short explanation abou PID _compact) Or if someone have PID realised in SCL source can it share? Thank's

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1/13/2014 11:02 AM	Rate (0)
Elux_Peter Member Joined: 12/13/2011 Last visit: 5/23/2014 Posts: 7 Rating: (0)	Hi I built a testbench which uses heater with solid state relays (0-10V). Instead of using PID a made an easy regulator myself which gives a minimum of 40% and a maximum of 80% of the power, but that percentage could be easily change in the code. Attach a picture of the code. Attachment Temp_regulator.jpg (571 Downloads)

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1/13/2014 10:00 PM	Rate (0)
Milosh Silver Member Joined: 8/16/2010 Last visit: 11/7/2019 Posts: 549 Rating: (6)	Peter, thank's for reply... But I'm interesting in PID... So I need explanation about PID_Compact (Manual parameters, tuning etc.) Which steps to do to configure PID_Compact? And how to control temperature via digital output (heater) with PID control?

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1/15/2014 8:36 AM	Rate (0)
koenb Silver Member Joined: 6/26/2009 Last visit: 11/7/2019 Posts: 120 Rating: (17)	Hi Milosh , You may find something here : /tf/WW/en/Posts/55600#top In my opinion it is better to use pid block with output in percent than the output_PER ( see configuration / basic settings for the PID compact block ) If your solid state relays can be driven with a analog signal the easiest way is converting the percentage to analog signal with the Scale_X instruction. If the SSR is digital I would convert the percentage to a timeproportional on/off digital. ( easy to do with a cyclic counter ) For the valve use PID compact equipped with a servo positioner , PID 3 step for a 3point controlled valve ( only open - close command ) koenb

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1/15/2014 9:49 AM	Rate (0)
Milosh Silver Member Joined: 8/16/2010 Last visit: 11/7/2019 Posts: 549 Rating: (6)	koenb If the SSR is digital I would convert the percentage to a timeproportional on/off digital. ( easy to do with a cyclic counter ) koenb Thank's for reply, but how to do that... Can you share example please...

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1/15/2014 1:41 PM	Rate (0)
koenb Silver Member Joined: 6/26/2009 Last visit: 11/7/2019 Posts: 120 Rating: (17)	Milosch , A simple and basic example to start with ... Attachment Time_prop_output.jpg (524 Downloads)

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1/15/2014 2:56 PM	Rate (0)
Milosh Silver Member Joined: 8/16/2010 Last visit: 11/7/2019 Posts: 549 Rating: (6)	koenb, Now understand... So, if output value greater then increment value turn on output, else output is off...

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1/19/2014 4:23 PM	Rate (0)
BryanG2001 Bronze Member Joined: 4/20/2011 Last visit: 11/11/2018 Posts: 113 Rating: (21)	You asked about PID in SCL. I posted one here back in July: /tf/WW/en/Posts/95449

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