I'm a novice to labview, 1st time using it, please bear with me.
Bascially, I run into problems of tuing a temperature controller to provide expected control on the temperature, which should be around plus/minus 1 C, maximum of around plus/minus 2C, and right now is around plus/minus 20 C.
Current situation and problems:
1. Omega Platinum temperature controller with a SPDT mechanical relay connected to a heating mantle to provide the output, and omega J type thermal couple to probe the temperature. The temp controller is currently running under PID control.
2. There is around plus/minus 20C oscillation around the setting point, even after auto-tuning and manually tuning the PID parameters. Please see attached image. And the ebb of oscillation around the setting point may be related to the Fuzzy Logic adaptive tuing of the temp controller, not sure about it.
3. And this temp controller comes with a mini-usb port, I was able to connect and control the temp controller with laptop through a mini-usb and usb line, through the configurator software provided by Omega.
Preliminary ideas and possible solutions that need your professional inputs:
1. I doubt that the auto-tuing algorithm in the firmware of Omega platinum temp controller is capable of finding the sweet spot of PID values, since multiple trial-and-error on tuning PID generated more confusions and frustrations. So I'm thinking about using the PID Autotuning (Temperature) of labview to optimize the PID parameters. Please correct me if I'm wrong over here.
2. Currently, I'm trying to use "Platinum_MB_Example Serial Master.vi" provided by Omega to connect labview to this temp controller (Attached). Even though the configurator software provided by omega could communicate with the temp controller through USB, I had no luck to connect the labview to the temp controller. Should I install specific driver or put the port number to make the communication open? I knew the port number of USB, but I'm not sure how to connect or if that's possible to connect the labview to this temp conroller through USB.
3. In case I was able to control this temp controller with labview, how could I add the PID Autotuning (Temperature) function to the original VI provided by omega?
Link to this temp controller is as following:
http://www.omega.com/pptst/CNPT_SERIES.html
Your time and help on this are gratefully appreciated.