The other day I got to work on a piece of lab equipment. They had replaced the temperature controller for the bottom platen of a bench top press and couldn’t get the new controller to work right. First thing I did was check the wiring and no problems were found. Using the knowledge I gained from over 30 years of working on instrumentation, I checked the thermocouple to make sure it had the correct resistance. No problem there either. Next I checked the model number on the temperature controller because E-Bob knows that temperature controllers are configured for specific inputs and outputs and the model number tells how they are set up. They had the correct controller.
At this point I fired the unit up and checked the output, which in this case was a power mechanical relay. I noticed right away the contacts on the relay were only staying closed but for a second or two. The controller was not outputting the correct signal to allow the heating element to heat the platen. I started checking the temperature controller settings. E-Bob found a few things wrong with the settings. The main problem was the controller was set for manual and a very low output. I also found that the PID values were still at their defaults. I changed the PID values to the same ones used in the top platen because they were identical systems. E-Bob finished up by testing the system and everything worked well.
This is just another example of how E-Bob Technical Services works on process controllers and instrumentation. I have over 30 years experience working on control systems. E-Bob has worked on everything from bench top analytical equipment to production plant controls and instruments. If you are having problems with a control system or instrument, try giving E-Bob a call.
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