KROHNE IFC 110 Converter - Manual (Page 78)

Sect. 7.7 Part C Special applications, functional checks, service, and order numbers
78 IFC 110 F 05/2003
Checking the setpoint reading
1)
Switch on the power supply and allow at least 15 minutes for ”warming up”.
2) Turn switch D (GS 8 A front panel) to ”0”.
3) Adjust zero to 0 or 4 mA with the 10-turn potentiometer P (GS 8 A front panel), depending
on the setting in Fct. 1.05, deviation <± 10 µA.
4) Calculate the position of switch Y and displayed setpoints ”I” and ”f”.
4.1) X =
Q
100%
× K
GK × DN²
Q
100%
full-scale range (100%) in unit volume V per unit time t
GK flow sensor constant, see instrument nameplate
DN meter size DN in mm, not inches, see instrument nameplate
t time in seconds (sec.), minutes (min.) or hours (h)
V unit
volume
K constant according to the following table
t Sec min h
V
liters 25 464 424.4 7.074
m³ 25 464 800 424 413 7 074
US Gallons 96 396 1 607 26.78
4.2) Determine position of switch Y: use table (GS 8 A front panel) to determine value Y which
comes closest to factor X and meets condition Y
≤ X.
4.3) Calculate setpoint reading ”I” for current output: I = I
0%
+
Y
X
(I
100%
- I
0%
) in mA
I
0%
current (0/4mA) at 0% flow rate
I
100%
current (20mA) at 100% flow rate
4.4) Calculate setpoint reading ”f” for pulse output: f = × P
100%
in Hz
Y
X
P
100%
pulses per second (Hz)
at 100% flow rate
5) Turn switch D (GS 8 A front panel) to ”+” or ”-” (forward/reverse flow).
6) Set switch Y (GS 8 A front panel) to the value determined as described above.
7) Check setpoint readings I and f, see items 4.3 and 4.4 above.
8) Deviation < 1.5 % of setpoint. If higher, replace signal converter, see Section 8.7.
9) Linearity test: set lower Y values, readings will drop in proportion to the calculated
values for Y.
10) Switch off power supply after completing the test.
11) Disconnect the GS 8 A.
12) Re-assemble in reverse order (items 2 to 1 ”in connection of GS 8A”).
See also illustration in Section 8.1 and 8.7.
13) The system is ready for operation after the power supply is switched on again.
Example: see next page.