FY operation manual 40
11. Functional Descriptions
11.1 PV bias
Description
The FY/FA series controller offers PV bias for input calibration, PV bias functions correct
the deviation of each sensor, as well as PV difference between controllers.
Function Diagram
PV bias (PV.OS)
PV ratio (PV.OH)
time
Temperature
200
°
C
198
°
C
0
°
C
2
°
C
Sensor PV
Controller PV
PVOS=+2
°
C
PVOH=5051
time
Temperature
200
°
C
198
°
C
0
°
C
Sensor PV
Controller PV
Controller PV=Sensor PV
Adjust Controller PV
Parameter
Parameter
Symbol
Content
Range
Default
Level
Hide/
Display
MAX
MIN
PVOS
PV bias(for zero)
PV = PV + PVOS
199.9
-199.9
0
Level 3
SET6.2
PVOH
PV bias(for span)
PV = PV x (PVOH / 5000) + PVOS
9999
0
5000
Fast
SET6.2
Examples
PV bias (PVOS) adds bias to the Measured value(PV):
When two controllers measure the temperature of the same type of load, the measured values of the respective characteristics of
the sensors are displayed as
Controller A : 200°C Controller B : 195°C
As shown above, Controller B is compensated by PV offset (PVOS) The PV.OS parameter value must be corrected by +5°C.
The display value will be changed to 200°C, Same as Controller A, but Controller B will show 5°C at 0°C.
Parameter setting
Level
Parameter
Set value
Description
4
SET6.2
1
Display PVOS
3
PVOS
5
PV adds +5°C
Fast
PVOH
5000
PV ratio unchanging
Example 2
PV ratio (PVOH) is a multiplier to be applied to the measured value(PV):
When two controllers measure the temperature of the same type of load, the measured values of the respective characteristics of
the sensors are displayed as
Controller A : 200°C Controller B : 195°C
As shown above, if Controller B is compensated by the PV ratio (PVOH), then the PVOH parameter value is adjusted to display
at 200°C. Consistent with Controller A, Controller B will show 0°C at 0°C.
Parameter Setting
Level
Parameter
Set value
Description
4
SET6.2
1
Display PVOS / PVOH
3
PVOS
0
PV bias unchanging
Fast
PVOH
5129
PV ratio=(5129/5000)=1.0258
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