Ratio Station (Templates 16 And 17) - ABB C505 User Manual

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.
Local Ratio
•1 Remote Ratio
I/P3
Wild Variable
I/P2
•1 Template 17 only
Wild
Variable (WV)
Process
Variable
(PV)
OP1
Wild
Variable (WV)
Process
Variable
(PV)
OP1
•1 Only displayed if enabled in Level B, Operator Configuration – see Section 4.7.
L
L R
rAtO
Fig. 2.9 Ratio Station
55. 0
50. 0
70
•1
bIAS
0. 0
70
2 OPERATOR LEVEL...
Manual Output
WV x rAtO + bIAS
WV
Actual Ratio
Process Variable (PV) – Bias
=
Wild Variable (WV)
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
Analog
Output
OP1
display.
27