Pid Control; Hardware; Connections - Siemens Milltronics BW500 Operating Instructions Manual

PID Control

The PID control algorithm in the BW500 is designed specifically to work for feed rate control
applications. It is based on motor control type algorithms and includes several anti-wind up
provisions.
One way to prevent wind up is to monitor the input speed frequency from the weighfeeder. If the
input frequency drops below 5 Hz, the PID control output freezes at its current value. Otherwise,
the output winds up to 100% if the feeder is shut off while there is still a set point greater than
zero. When the feeder is turned back on, there would be a surge of product flow until the system
regains stability. With anti-wind up, the feeder can be stopped and started with minimal
disruption to the controlled flow rate.
To operate the BW500 as a controller, address the following:
● hardware
● connections
● setup and tuning
● programming
Note
PID control not available on the BW500/L.
9.1

Hardware

For the BW500 to operate as a controller, install the optional mA I/O board. Refer to Installation
(Page 21).
9.2

Connections

Connections to process instruments, in addition to standard operating connections, must be
made.
Refer to:
● Installation (Page 21), specifically:
● Relay Output (Page 40), for relay connections
● mA I/O board (Page 43), for mA input and output connections
● Auxiliary Inputs (Page 38), for optional remote control
BW500 and BW500/L
Operating Instructions, 12/2016, A5E33482052-AD
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