WIKA 851 - Manual (Page 15)

WIKA operating instructions magnetic snap-action contact model 821 15
GB
2003325.03 03/2011 GB/D/F/E
8. Commisioning, operation / 9. Contact protection ...
8.4 Adjusting the set pointers
The setting of the set points is achieved using the adjustment lock in the
window with the aid of the adjustment key (part of the scope of delivery;
found in standard instruments on the side of the terminal box).
The set pointers for the limit switches are freely adjustable over the full
scale range. For reasons of switching accuracy, switching reliability and
service life of the mechanical measuring systems, the switch points
should be between 10 % and 90 % of the measuring span.
Commissioning
During the commissioning process pressure surges must be avoided at
all costs. Open the shut-off valves slowly.
9. Contact protection measures
Mechanical contacts must not exceed the specified electrical values for
switching current and switching voltage independent of each other, not
even for a short time only.
For capacitive or inductive loads we recommend one of the following
protective circuits:
Set pointer
Adjustment lock
Removable
adjustment key