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4.2
C
ONNECTION TO THE
F
LOW METER
Connection to the flow meter is required for any Sentinel 2 that uses a pressure profile
that is dependent on flow (i.e., flow or combined time and flow).
For other situations it is optional and will be used only by the data-logger functions.
The water flow can be detected by a flow meter near the PRV. The Flow information is
transferred to Sentinel 2 by means of an electrical interface in the Control Box.
Various hardware interfaces exist for collecting flow information, including:
•
Collection of meter pulses (from a contact or a volt-free pulse output).
This type of interface is suitable for supporting the PRV control functions.
(Refer to section 6.1.1 for cable diagram).
•
Analogue (4-20mA) input for connection to a compatible output of a flow meter.
This type of interface is
unsuitable
for supporting the PRV control.
It can be used as a measurement interface option for logging purposes only.
Connect the Flow-meter end
of the cable to the flow meter.
Then connect the cable to the
Control box via the 4-pin
connector labelled “Flow”.
4.3
C
ONNECT
E
XTERNAL
P
RESSURE TRANSDUCERS TO
S
ENTINEL
2
Where the Sentinel 2 is supplied with external pressure transducers, these must be
connected to the relevant MIL-spec connector on the control box.
Determine which transducer will be used for measuring upstream pressure and which
will be used for measuring downstream pressure. Check the range of each transducer is
suitable for use (refer to the label on the cable of HWM supplied external transducers,
as described in section 4.4).
Plug each transducer into the correct Sentinel 2 MIL-spec connector:
•
Be sure to connect the upstream pressure transducer to the connector labelled
“PRV Inlet pressure”.
•
Be sure to connect the downstream pressure transducer to the connector
labelled “PRV outlet pressure”.
Ensure connectors are correctly fitted so that they are watertight.
