M-system PU-2A, Operation Manual

Page: 24 / 40

24 PU-2A USERS MANUAL EM-9255-C Rev.14
HOW TO CALCULATE GAIN/BIAS FOR TEMP. & PRESS. COMPENSATION (JFK) ....
TEMPERATURE COMPENSATION FOR DP FLOWMETER
X
3
: 100%
ORIFICE
DESIGN STANDARD
X
3
: 0%
0 K (Kelvin)
T
3
°C
T
2
T
1
-273.14
K
1
= I/O range scaling factor
K
1
= 1 when input & output ranges are identical.
K
3
=
T
3
– T
1
A
2
=
T
1
+ 273.14
T
2
+ 273.14 T
2
+ 273.14
[EXAMPLE]
Temp. range of DP flormeter: 0 – 400°C
Design standard of orifice: 300°C
K
1
= 1
K
3
=
400 – 0
= 0.698
300 + 273.14
A
3
=
0 + 273.14
= 0.4766 = 47.66%
300 + 273.14
PRESSURE COMPENSATION FOR DP FLOWMETER
Atmospheric pressure = 101.3 kPa (abs)
• Absolute Pressure
K
2
=
B
3
– B
1
A
2
=
B
1
X
2
: 100%
ORIFICE
DESIGN STANDARD
X
2
: 0%
0 kPa (abs)
B
3
B
2
B
1
0
G
3
G
2
G
1
-101.3
Absolute
Pressure
kPa (abs)
Gauge
Pressure
kPa (G)
B
2
B
2
• Gauge Pressure
K
2
=
G
3
– G
1
A
2
=
G
1
+ 101.3
G
2
+ 101.3 G
2
+ 101.3
[EXAMPLE]
Press. range of DP flormeter: 0 – 980 kPa (G)
Design standard of orifice: 686 kPa (G)
K
1
= 1
K
2
=
980
= 1.245
686 + 101.3
A
2
=
101.3
= 0.1287 = 12.87%
686 + 101.3