KROHNE IFC 090 Converter EN - Manual (Page 62)

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Check of setpoint display
1) Switch on power source, allow at least 15 minutes’ warm-up time. .
2) Set switch D (front panel of GS 8A) to “0” position.
3) Adjust zero to 0 or 4 mA with the 10-turn potentiometer P (front panel of GS 8A),
depending on setting in Fct. 1.05, deviation <±10 µA.
4) Calculate position of switch Y and displayed setpoints ”I“ and ”f“:
4.1) X =
Q
100%
x K
GK x DN 2
Q
100%
full-scale range (100%) in volumetric unit V per unit time t
GK primary constant, see instrument nameplate
DN meter size DN im mm, not inches, see instrument nameplate
t time in seconds (Sec), minutes (min) or hours (hr)
V volumetric unit
K constant, according to following table
t Sec min hr
V
Liter
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 (front panel GS 8A) 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 (I
100%
- I
0%
) in mA
X
I
0%
current (0/4mA) at 0% flowrate
I
100%
current (20mA) at 100% flowrate
4.4) Calculate setpoint reading ”f“ for pulse output: f = Y x P
100%
in Hz
X
P
100%
pulses per second (Hz)
at 100% flowrate
5) Set switch D (front panel GS 8A) to position “+“ or “-“ (forward / reverse flow).
6) Set switch Y (front panel GS 8A) to the value determined by the method described above.
7) Check setpoint readings I and f, see points 4.3 and 4.4 above.
8) Deviation <1.5% of setpoint. If greater, replace signal converter, see Sect. 8.7.
9) Test of linearity: set lower Y values, readings will drop in proportion to the calculated Y
values.
10) Switch off power source after completing the test.
11) Disconnect the GS 8A.
12) Reassemble in reverse order, see points e) – b) under “electrical connection”,
see illustration in Sect. 8.5.
13) The system is ready for operation after the power source has been switched on.
Example: see overleaf
Note:
Sticker on the GS 8 primary head simulator still gives values for
“inch” flowmeter. Do not use any more !