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PID autotuning (pretuning) Pt100 PID_Compact problem
altan posted a topic in SiemensDear colleagues and siemens experts, I''m new in siemens. As all I make my program for PLC, but I need help with PID autotunig (pretuning) I use : 1.CPU 1214C DC/DC/DC (6ES7214-1AG40-0XB0) 2. 6ES7214-1AG40-0XB02. 16IN/16 OUT DC/DC/DC (6ES7-223-1BL32-0XB0) 3. 2x 6ES7231-5PD32-0XB0 ( 4 channel RTD analog module - PT100) We use 7(seven) Pt100 points with 7(seven) heaters ... so I need 7 additional outputs..... [you can see example of wiring in attached pic 6es7231-5pd32-0xb0-modules.jpg] Maximum heating point is around 220 degrees. I make my configuration for PID_Compact : 1. Basic settings 1.1 Controller type : Temperature : °C Set mode to : Pretuning ( sometimes I make it Automatic mode) 1.2 Input_Per(analog) -----> Output_PWM 2.Process value setting: 2.1 Process value limits: Process value high limit : 220.0 °C 2.2 Process value limits: Default 3. Advance setting 3.1Process value monitor : Default 3.2 PWM limits Minimum ON time : 0.5 sec Minimum OFF time : 0.5 sec 3.3 Output value : Default 3.4 PID parameters : Default I start Commissioning with these steps : 1. Measurement : Sampling time 0.5 Start 2. Start PID_Compact 3.Tuning mode : Start When I try first time my setpoint was 90 degrees , second time I try with 120 degrees. After 4-5 hours it stop more in Progress bar it stop when I reach a little more then 50%, and I stop PID. For heaters it is not normal to process to be 4-5 hours, there have some wrong. Example with 120 degrees : During process I make : When Input_PER reach 120 degrees I stop physical access to heaters. When Input_PER reach 100 degrees I start physical access to heaters So 4-5 hours is soo long time for this type process. Time to reach 120 degrees from 100 degrees is around 2-3 min. Time to fall from 120 degrees to 100 degrees is around 4-5 min. Total time for one whole cycle around : 8min. Sometimes when I set setpoint to 140, 150 degrees it writes me that output set value is to high after I give Start Pretuning ? Even sometimes when try for 120 degrees .... As all I want to start PID pretuning (autotuning) with setpoint 140 - 150 degrees. Which are minimum requirement to start PID autotuning with PID_Compact ? Could you send me some very simple example and steps that I must make or only steps ? I attached files in dropbox with images and program example, because I can't attached nothing here. This form don't give me access to attached something. So link is here : Even program is there. Thanks in advance Best regards : Altan