Flow rate
Example for the calibration of the current signal for flow-rate measurement
A current signal of 20 mA shall correspond to a flow rate of 10.0 m
3
/h; 4 mA shall correspond to a flow rate of 0,0 m
3
/h
SERV setting value
No.
Function
18
0.0
Calibration of current signal input from flow meter, terminal 32.
(–0.99...+0.99) (mA)
Actual flow rate (recorded with a test device)
8.0 m
3
/h
Reading of control value 18 of the controller
(see section on ’Control values’)
7.8 m
3
/h
Determine deviation
8.0 m
3
/h
– 7.8 m
3
/h
+ 0.2 m
3
/h
Calculate the deviation as a percentage of the flow rate corresponding
to 20 mA:
100%
∗
(++
0.2 m
3
/h
)
10 m
3
/h
=
+
2 %
Calculate the correction value (in mA) of the display range:
(
20
−
4
)
mA
∗
(++
2%
)
100%
=
+
0.32 mA
Enter the correction value in mA incl. sign (keys
).
Then, the corrected value of the flow rate is shown under control value no. 18 (for above example: 8.0 m
3
/h).
0
3
2
R
–
32
–
7 000458 003
