Kobold DON -2/4, Operating Instructions Manual

Page: 18 / 65

DON
page 18 DON K36/1222
7.3.5 Analog output 4-20 mA, 2-line (L0/LE option)
The L0 and LE (explosion hazard) options include a loop-powered 4-20 mA output.
The loop is powered by an external voltage source 16 – 32 V
DC
. The maximum
working resistance of loads connected in series (PLC-analogue input / electronic
displays) depends on the supply voltage level, namely:
Max. working resistance (ohms) = (+Vs – 9 V
DC
) / 0.02 A [ohms]
Example: +Vs = 32 V
DC
=> max. working resistance = 1150 ohms
+Vs = 16 V
DC
=> max. working resistance = 350 ohms
The load can be coupled at any point of the current loop, provided the polarity is
correct.
All DON devices with L0/LE options are factory-calibrated to the respective
measurement range end value. This setting should only be modified by the
manufacturer.
7.3.6 Calibration Factor (scale or K Factor)
The DON flowmeter is delivered with a factory calibration certificate. Within this
certificate, a calibration factor is provided. The calibration factor is a specific
representation of pulses per unit volume. (i.e. pulses per liter) for that specific
meter.
Measurement devices with attached electronics are factory pre-configured to the
corresponding calibration factor. Depending on the model, the calibration protocol
is based on either the flow rate display or the analog output.
For further details on the operation and parameterization of the electronic option
Zx and 1A…5A see operating instructions ZOK- (Ex).