KROHNE IFC 110 Converter User 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.