Valve Page; Calculation For Control Pulses, Steps And Deviation; Position-Proportioning Control; Regulator Travel Time - ABB COMMANDER 1900 Series Programming Manual

4.2.3 Valve Page

VALVE
PAGE
SELECt
CtrL 2
CtrL 1
NONE
Boundless
Position-
Proportioning
rAtIO
-. - -
bIAS
-. - -
dEAd b
--. -
rGL-t
----
dEAd b
--. -
4.2.4 Calculation for Control Pulses, Steps and Deviation (Boundless Control only)
Minimum 'ON' time of integral action pulses (for a fixed control
deviation)
Travel Time x Deadband %
=
%PB
Minimum (approximate) time between integral action pulses
(for a fixed control deviation)
Integral Action Time x Deadband %
=
2 x Control Deviation
Page Header – Valve Page.
To advance to
Set Up Control Page
Select Controller
Select the controller to be programmed (1 or 2).
Note. In the remaining frames press the
Ratio
The Ratio is a scaling factor, i.e. multiplies the position feedback input by the value set here.
Set the required feedback ratio, between 0.01 and 10.00 in 0.01 increments.
Bias
The Bias is an offset set as a percentage of the display full scale.
Set the required feedback bias, between –100.0 and +100.0% in 0.1% increments.
Dead Band
Percentage

Deadband

(% of Range
Set Point
Span
Return to
Select Controller

Regulator Travel Time

This is the time set for the regulator to travel from the fully open to the fully closed position or from
the fully closed to the fully open position.
Set the value required in seconds, between 1 and 5000 seconds.
Dead Band
Deadband is set as a percentage of the engineering range. Set a value which gives minimum
hunting of the regulator, between 0.0 and 10.0 in 0.1% increments.
Return to
Select Controller
(in seconds)
(in seconds)
4 CONTROL CONFIGURATION LEVEL...
press the switch.
switch to view the controller selected.
Deadband is set as a percentage of the position feedback span,
between 0.0 and 10.0%, to produce a deadband around the valve
control value. This gives minimum 'hunting' of the motorized valve.
Example – if the valve is to be driven to 50% open position and the
deadband is set to 4.0%, the motor stops driving when the position
feedback is 48%. The deadband is between 48% and 52%.
frame.
frame.
Duration of the proportional step
% Control Deviation
= 2 x
% Proportional Band
% Control Deviation
Set Point – Process Variable
=
Span
x Travel Time in Seconds
x 100%
35