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4.3 Volumetric flow monitoring
4.3.1 Volumetric flow quantity
The signals for measuring the volumetric flow quantity can be provided as follows:
1� Two switching signals for volumetric flow quantity limit values on output 1 and
output 2. On the switching functions → 4.7.
2� A frequency signal (10 Hz���10 kHz) on output 1�
On the frequency functions → 4.9.
3� An analogue signal proportional to the volumetric flow (4���20 mA or 0���10 V)
on output 2. On the analogue functions → 4.8.
4.3.2 Direction of flow
In addition to the flow velocity, the unit also detects the flow direction� An arrow on
the unit indicates the positive flow direction�
The flow direction can be inversed (→ 10.6.3).
► Use the supplied label to mark the changed flow direction�
Direction of flow in accordance with "flow direction"
> process value and display positive�
Direction of flow against the "flow direction"
> process value and display negative�
Only positive process values are processed for the signal output (limit
values and analogue values for volumetric flow)�
4.4 Consumed quantity monitoring (totaliser function)
The unit has an internal mass flow meter which continuously totals the volumetric
flow� The sum corresponds to the current consumed quantity since the last reset�
• The quantity meter takes account of the flow direction for totalisation�
-Flow according to the marked flow direction (arrow "flow direction"): meter
adds�
-Flow against the marked flow direction: meter subtracts (→ 10.6.12).
-Meter pulses are only provided as the sum increases� After subtraction
(consumed quantity decreases), the pulses are only provided again when the
consumed quantity has exceeded the previous maximum value�