Siemens Milltronics BW500, Operating Instructions Manual

Page: 109 / 220

BW500 and BW500/L
Operating Instructions, 12/2016, A5E33482052-AD
107
PID Control
9
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