KROHNE DWM 2000 LCD - Manual (Page 4)

4 Operating Instructions DWM 2000 D
2 Functions of the LCD indicator for the DWM 2000 D
2.1 Programmable parameters
2.1.1 Flow calibration
The G
K
can be modified in menu 2.1.3 in order to obtain the maximum accuracy at operating
conditions. A field calibration requires an accurate reference of velocity. The meter recalibration (G
K
modification) is also recommended after an exchange of electronics module.
The value of the new calibration constant (G
K
new) can be calculated as follows:
GK
new
= GK
old
x Va
Vm
with:
Va = actual velocity
Vm = measured velocity (reference value)
2.1.2 Current output adjustment
The minimum value (i
0%
) and the maximum value (i
100%
) of the current output at normal operating
conditions can be adjusted from menus 2.2.2. and 2.2.3.
The actual values of the i
0%
and the i
100%
must be measured with an accurate milliammeter in a
4...20 mA loop.
i
0%
must be in the range 3....12 mA. The factory setting is 4 mA.
i
100%
must be in the range 12....21 mA. The factory setting is 20 mA.
2.1.3 Time constant
The time constant value can be set in menu 2.2.4. This value represents the time needed to detect
63% of a simulated flow rate instantaneously raised from 0 to 100%. Time constant range : 5, 10,
15, 20, 25, 30, 50 m.