About Precision Tune Auto Care Precision Tune Auto Care began as a tune-up shop in Beaumont, Texas in 1977. Today, there are more than 250 locations throughout the United States. The company services every kind of vehicle on the road, and offers a 24-month/24,000 mile warranty, good at.
Rest room and office clean-quote made before starting repair work and not changed-have been going there for a long time for oil changes..
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The PV was originally a tank level and the OP was a VSD driven pump.But after seeing the erratic behaviour of the output, even at low gains, and without and relation to the tank level, I disconnected them, and fed fixed numbers into the PV and SP (which you can see as green and red flat lines on the graph) to rule them out as causes. Still the output (the blue line) is all over the place for no apparent reason.Of course PID control is based upon the error value, the difference between the PV and SP, and here the error value is clearly staying the same, as seen on the graph, so something else must be causing these large erratic changes in output. Auto tuning shop. It seems like people aren't reading/understanding this comment.Take note of the fact that the tank level instrument is not connected, I'm using a fixed internal value for the PV to eliminate potential external oscillations, hence the perfectly flat red line on the graph representing the PV.Also, more samples per second should not be required when the PV and SP (and therefore error value) are perfectly flat lines/steady values. I even tried setting the PB gain very low (0.1) and turning the Integral off (0) and this random output movement still persisted.I originally set up the PID controller using the instruction wizard in Micro/WIN using all the default settings.