ABB ControlMaster CM30 - Ratio Controller (Internal; External Ratio); Ratio Station (Internal; External Ratio)

ControlMaster CM30, CM50 and CMF310
Universal process controllers,
1
/4,
1
/2 DIN and fieldmount 8 Templates and Functionality
94 IM/CM/ED–EN Rev. X
8.3.4 Ratio Controller (Internal / External Ratio)
The ratio controller template configures the ControlMaster to regulate one process variable against another
based on a specified ratio. The unregulated variable or 'wild' variable is weighted by ratio and bias values
and this forms the control setpoint for the process variable. The ratio value applied to the wild variable can
either be a local value set on the front panel or a remote signal on an analog input.
8.3.5 Ratio Station (Internal / External Ratio)
The ratio station template configures the ControlMaster as an Indicator and setpoint generator. The
unregulated 'wild' variable is weighted with ratio and bias values and is then retransmitted to a slave
controller.
AIN 1
AIN 2
AIN 3
Local
Ratio
Manual
Output
A/M
OP
PID
O/P
Loop1
PID Control
PV
S
P
Analog
Output
Output Type
AO1
PV – Bias
WV
WV
WV x Ratio
+ Bias
A
c
t
u
a
l
R
a
t
i
o
AIN 1
AIN 2
AIN 3
Local
Ratio
PV – Bias
WV
WV
WV x Ratio
+ Bias
PID
O/P
Manual
Output
A/M
OP
Analog
Output
Output Type
AO1
PV
Actual Ratio