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Showing results for tags 'pid tuning help require'.
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Dear All i am trying to control pneumatic valve with level of tank. User set the desired level and pneumatic valve control the level in tank.. Tank level is 4-20ma signal. With empty tank it show value if 3 and if level is full it shows reading of 151. I am using FX3U PLC for this purpose. I tried to control it using PID function. I set Kp to 300 and Ti to 2sec derivative term is zero. With these set parameters system act just like a switch it turn on valve full open when PV(Level measured value) is less then SV(level set value) and turn the valve completely off when PV is greater then SV. Kindly help me to tune the system properly Thanks Bilal Khan
altan posted a topic in MitsubishiDear all, Do you have some ready examples for Mitsubishi fx5u where you use PID ? I use two analog input from 0-10V and two PLC output and I want to head 2 heaters. So how can I use PID autotuning? As I see in examples in manual, there also have other parameters, which I must set, except PID function. Thanks in advance . :)
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