EN
WIKA operating instructions differential pressure gauge, model DPGT40
19
14093267.05 09/2020 EN/DE
6. Commissioning, operation / 7. Options and accessories
6.3 Setting up a voltage supply
The voltage supply is made via a power supply unit or a control unit which
provides the energy limitation.
The supply voltage for the pressure gauge must be made via an energy-limited
electrical circuit in accordance with section 9.3 of UL/EN/IEC 61010-1, or an LPS
to UL/EN/IEC 60950-1, or class 2 in accordance with UL1310/UL1585 (NEC or
CEC). The power supply must be suitable for operation above 2,000 m should the
pressure gauge be used at this altitude.
7. Options and accessories
7.1 4-way valve manifold
■
Isolation of the ⊕ and ⊖ process lines for
removing
or
testing
the measuring
instrument without interrupting the running process operation.
Protection
of the instrument against
excessive overpressure loading, such as
in pressure tests and undefined operating
conditions (including intermittent shutdown).
■
Pressure compensation for
zero point
checking
with running processes, and
avoiding one-sided overpressure loading
during start-up and operation phases (with
opened pressure compensating valve).
■
Venting
the measuring lines with liquid
media and
flushing
of the measuring lines,
in order to remove contamination.
Vent valve
Shut-off valve
⊖ side
Shut-off valve
⊕ side
Pressure
compensating valve
Specifications for handling
■
Sequence of operations to
start measurement
1. Open the pressure compensating valve (middle valve spindle)
2. Open the shut-off valve for the negative media chamber (⊖, right-hand valve)
and the positive media chamber (⊕, left-hand valve)
3. Close the pressure compensating valve
■
Sequence of operations to
flush/vent
the measuring lines
1. Start: Open the shut-off valve for the ⊕ and ⊖ media chamber, open the
pressure compensating valve and vent valve
2. Finish: Close the pressure compensating valve and vent valve
