West Control Solutions Pro-EC44 - Manual (Page 217)

Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013 Page 210
Control Configuration
A sub-menu of the configuration menu used to adjust the parameters that relate to the
control of the process (enabling control, auto/manual mode, control type and action, PID
tuning terms, power limits, sensor break action, setpoint values and setpoint selection).
Also refer to: Configuration Mode; Control Action; Control Enable; Local Setpoints; Manual
Mode; PID; Setpoint Selection and Tuning.
Control Deviation
Control Deviation is the difference between the process variable value and the actual
setpoint. The control deviation error is equal to PV
– SP. This value can be monitored using
the bar-graph (±5% of span). An excessive deviation warning can be given by using a
deviation or band alarm.
Also refer to: Actual Setpoint; Alarm Types; Band Alarm; Bar Graph; Deviation Alarm; Input
Span; Process Variable and Setpoint
Control Action
This refers to the control loop(s) primary power output direction. Reverse action is typically
used with heating applications as it increases the correcting variable as the process variable
falls. If a secondary output has been configured, its action is always the opposite of the
primary output.
Also refer to: Control Type; Correcting Variable; Direct Acting Control and Reverse Acting
Control.
Control Enable/Disable
The PID controller outputs can be temporarily turned off by disabling the control. When
control is disabled t
he setpoint value is replaced by “OFF”. All other functions continue as
normal. The control enable/disable function can be controlled from the control configuration
sub-menu, via a digital input or optionally from the operation menu if enabled in the display
configuration sub-menu.
Also refer to: Digital Input; Display Configuration; Operation Mode and PID
Control Power Alarm
A control power alarm is based on the output from the PID control algorithm. It can provide a
warning if the PID output rises above or falls below a set value. This is often used in
conjunction with the minimum alarm duration time so that very brief power output peaks can
be ignored.
Also refer to: Alarm Duration Minimum; Alarm Types and PID
Control Type
This defines if a control loop has Single (unidirectional) or Dual (bidirectional) control outputs.
Single outputs have a primary output only. This can drive the process in one direction (e.g.
heat only, cool only, increase humidity etc). Dual outputs have both primary and secondary
outputs which can force the process to increase or decrease (e.g. heat & cool, humidify &
dehumidify etc).
Also refer to: Control Action; PID; Primary Proportional Band; Process Variable; and
Secondary Proportional Band.