WIKA DPS40 - Manual (Page 20)

GB
WIKA operating instructions DELTA-plus, DELTA-comb and DELTA-switch 20
14093265.01 03/2014 GB/D/F/E
6. Commissioning, operation / 7. Options and accessories
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 avoid-
ing 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 compen-
sating valve
Switch point and zero point setting
The switch point and zero point setting is made by adjustment screws in the front,
which, depending on the instrument model, are accessible by loosening the win-
dow or the locking screws.
By turning the adjustment screw using a screwdriver the desired zero point is set.
The switch points are set at the factory when the set points are given.
An assistant scale enables an accurate setting of the switch point and indicates
the current set point.
If an even more accurate switch point setting is required, a reference standard
should be used for the adjustment.
Commissioning
During the commissioning process pressure surges must be avoided at all costs.
Open the shut-off valves slowly.