VEGA VEGAMET 624 - Manual (Page 20)

20
6 Setup with the integrated display and adjustment unit
VEGAMET 624 • 4 … 20 mA/HART
28969-EN-130701
Digital HART transmission
For transmission via HART, VEGAMET 624 must be informed which
sensor value should be used for further processing. Depending on
the sensor type, this can be distance, pressure or temperature. With
all HART sensors, the unchanged initial value of the sensor is always
transmitted to VEGAMET 624. Thus, adjustment must always be car-
ried out on VEGAMET 624, never on the sensor. Different parameters
and measuring units are available.
When HART sensors from other manufacturers are connected, the
options PV (Primary Value) and SV (Secondary Value) are available.
The prerequisite for this is the support of the HART commands 0, 1,
3, and 15. This information and which measured values are transmit-
ted can be found in the operating instructions manual of the respec-
tive sensor manufacturer.
The measured variable defines the applicaton of the measurement
loop, the following settings are available depending on the connected
sensor:
•
Level
•
Process pressure
•
Universal (for sensors of other manufacturers)
Through the adjustment the input value of the connected sensor is
converted into a percentage value. This conversion step allows any
input value range to be depicted in a relative range (0 % up to 100 %).
Before carrying out the adjustment, the requested adjustment unit can
be selected. With input selection "Analogue", the adjustment unit is al-
ways "mA". If the HART input is activated, the available unit depends
on the sensor type. With radar, ultrasonic and guided microwave this
is always the distance in metres or feet "m(d)" or "ft(d)", and with pres-
sure transmitters it is e.g. "bar" or "psi".
The following illustrations and examples relate to the min./max. ad-
justment of a radar sensor with HART communication.
Meas. loop - Parameter
Meas. loop - Adjustment