Milltronics ACCUMASS BW500, Инструкция по эксплуатации

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PL-565 Accumass BW500 Page 95
P
ID Control
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.
In order for the BW500 to operate as a controller, the following must be addressed:
✔
hardware
✔
connections
✔
setup and tuning
✔
programming
Hardware
In order for the BW500 to operate as a controller, the optional mA I/O board must be
installed. Refer to Installation on page 13.
Connections
Connections to process instruments, in addition to standard operating connections,
must be made.
Refer to Installation on page 13, specifically:
Relay Output on page 25, for relay connections
mA I/O board on page 15, for mA input and output connections
Auxiliary Inputs on page 23, for optional remote control
Connect the BW500 as either a:
1. setpoint controller – load control
2. setpoint controller – rate control
3. setpoint controller – rate and load control
4. setpoint controller – external process variable with or without rate and load control
PID loop mA output terminals mA input terminal
(mA I/O) (mA I/O)
1 2 1 & 2 1 5 & 6
2 3 3 & 4 2 7 & 8