Siemens Milltronics BW500, Operating Instructions Manual

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PID Control
9.4 PID Setup and Tuning
BW500 and BW500/L
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Operating Instructions, 12/2016, A5E33482052-AD
The PID control function of the BW500 can be configured to operate in several modes.
● controller output: direct acting
● feedback: rate, load, or external
● control: local or remote (ratio) setpoint
9.4 PID Setup and Tuning
Proper tuning of the control PID terms is essential to system operation and optimum
performance from the feeder. The recommended procedures for tuning the PID control terms at
initial start-up are described in this section.
9.4.1 Initial Start-Up
Although the default values of the P, I, D, and F terms will suit the majority of applications,
shearing weigh feeders in particular, some tuning will be necessary nonetheless.
There are several techniques and procedures for tuning conventional PID controllers, some work
better depending upon the application. We recommend using "closed-loop cycling" for the
BW500 integrator/controller for feed rate control. This technique focuses on tuning the P term
first while disabling the I and D terms. This is followed by adding andtuning the I term, then the D
term. To outline this procedure:
1.
With the P term set to its default value of 0.400, disable the I, D, and F terms by setting them
to 0.000.
2. Enter a feed rate setpoint that is 30% of the designed maximum flow rate.
3. Having applied the test weights or chain provided, start the feeder and observe the time it
takes the feeder to reach setpoint, also observe the oscillation around setpoint.