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  1. I need some advice how to tune PID properly. The PID is only PI type (two mode) and its overshooting frequently. Assuming I need to tune P with starting incrementing by very small steps till PID oscillates.  Once the P is established then will be tuning I , again with small increments till PV follows SP.  So this is my assumption below but would like someone to comment on it as I haven’t had to do it before , been learning PLC for 4 months now.  Do I need to start a machine and then start tuning PID or can this be done in more friendly way , offline ?
  2. Autotuning Kinetix 350

    Hell PLC World! I have been trying for several weeks in my spare time at work to tune an Allen Bradley Servo Motor.  Below is the list of hardware I am currently using: - CompactLogix Motion Controller (1780-L33ERM) - Kinetix 350 Driver (2097-V34PR5-LM) - MPL Series Rotary Servo Motor (MPL-B310P-MJ74AA) I have been using RSLogix5000 for testing and I plan to use it to develop a simple conveyor type program later.  I have tried a list of things which will be below, but to no avail, I cannot simply jog the motor for any period of time without triggering a position, velocity or bus voltage error.  I have tried changing the motor, driver and feedback cable to no avail.  Here is the process I have used: 1) Add the hardware to RSLogix5000 (PLC, Driver and Motor) 2) Configure the motor 3) Run the hookup test.  This works flawlessly.  The motor will slowly turn independently on the feedback test for as many revolutions as I input.  This is what makes me think I am doing something wrong in the tuning process. 4) Run autotune process with the velocity, acceleration and jerk set well below the limits of the hardware.   5) Attempt manually control motion 6) Recieve error I have tried changing the input from trapezoidal to S-Curve, changed velocity and position limits, manually tuned velocity gains in a myriad of configurations.  I have swapped legs on the 3 phase input (which made matters worse). I suppose it is possible that multiple pieces of hardware are faulty because this equipment was previously used, but I still cannot wrap my head around why the hookup test would work so flawlessly, yet I cannot just get the servo to rotate at an equivalently low speed. If anyone recognizes my mistake, I would be eternally grateful.  I am an intern studying control systems in graduate school and as popular as AB is, I would sure like to get some experience with it.  Thanks in advance!  
  3. Dear 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 . :)
  4. pid tuning

    Hi there! I have a problem with a process. The bottom line is I have a quite big asynchronous motor (about 110kw), with this motor I would like to fill a pool. There is a sensor that monitors the level. Im setting the PID for the motor control, it seems to be good, but unfortunately the fultuation is very big, however the level is perfect. I send a 4-20 mA signal to the inverter. Actually, it is almost everytime changing. I think it is not good for the motor. the changing scale is between 100 and 600 rpm ... What do you guys think ? Can this cause early motor or inverter failure? I had a thought, I did that I was doing an average and sent the current process data every 3 seconds. It causes that, the motor rpm 100 or 600 rpm.. nothing else, and change it about every 3 or 6 seconds,  because of te too much error I think.  How can I solve the this problem. The material runs out evenly from the pool, but the control variable is still bouncing. I monitored the process variable and the control variable too and the error too. I noticed that the output only changes when it is very close to the setpoint. for example the setpoint is 5000. And if the process variable is 4950 then the output is 100%. and if the process variable is 4992 then the output is about 67% but, the if the process data is 5010 then the output is 0%.   I'd expect that, for example that if the process variable is 2000 then the output is will be 100%. but the process data is 4000 then the output will be 50 % ... and so on.... so I hope I can find a permanent output value.  I dont know, maybe I made some mistake.... pls help me in this situation. Thank you.        
  5. PID Tunning

    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
  6. Servo Motor Tuning

    Hi i am new to Mitsubishi servo drives, i want to know how to Tune the Mitsubishi (MR-JE-A-200w) servo drive Can any one guide me please  
  7. Dear 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[1200] degrees I stop physical access to heaters. When Input_PER reach 100[1000] 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