27
2
OPERATOR LEVEL…
2.10
Ratio Station (Templates 16 and 17)
The ratio station provides a set point for a subsequent slave controller. The wild variable (WV) is
weighted by ratio (rAtO) and bias (bIAS) values and is then retransmitted as an analog output value.
•1
Only displayed if enabled in Level B, Operator Configuration – see Section 4.7.
Actual Ratio
=
Desired Ratio
Adjustable in local control only.
Ratio Setpoint Output
= (WV x Ratio) + Bias
[–10 to 110%]
Adjustable in manual control only.
Bias
[In engineering units]
Return to
Actual Ratio
display.
bIAS
0.0
55.0
50.0
Wild
Variable (WV)
Process
Variable
(PV)
70
OP1
70
OP1
Process
Variable
(PV)
•1
Wild
Variable (WV)
WV x
rAtO
+
bIAS
I/P3
Manual Output
I/P2
WV
rAtO
L
L
R
Local Ratio
•1 Template 17 only
Remote Ratio
Wild Variable
•1
Analog
Output
OP1
Fig. 2.9 Ratio Station
Process Variable (PV) – Bias
Wild Variable (WV)