West Control Solutions MRC 9000 - Manual (Page 236)

Edition 3
Rev G
Section 13 13-5
CASCADE control uses two “control blocks”. The output of one controller is the setpoint of a second controller.
Ratio and bias (see Steps 20 & 21) need to be applied to the connecting setpoint. Because of the interaction
between controllers, cascade control will only apply to controllers 1 and 2, or 3 and 4, used in pairs, with 1 and 3
being the first controller.
FEEDFORWARD adds a 0-100% value to the PID output. When feedforward is used, the feedforward source
(Step 22) is scaled to provide a 0-100% value to work with the loop output of 0-100%. Depending on the limits of
the input, and the scaling, the FF-term may be limited to less than 100%.
SP + PID adds a term that makes the output primarily proportional to the setpoint, but with PID capability added.
This is used primarily for flow control.
4. Press the to advance to the next parameter, OUTPUT 1 TYPE.
Cx OUTPUT 1 TYPE
NONE/OFF
Selections
NONE/OFF
ON/OFF DIRECT
ON/OFF REVERSE
PID DIRECT
PID REVERSE
5. Press the to advance to the next parameter, OUTPUT 2 TYPE.
Cx OUTPUT 2 TYPE
NONE/OFF
Selections
NONE/OFF
ON/OFF DIRECT
ON/OFF REVERSE
PID DIRECT
PID REVERSE
Press the to change, then or
to desired choice, then press the .
Press the to change, then or
to desired choice, then press the .