Indicator Correction; Alarm Contacts - WIKA 73 Betriebsanleitung

5. Indicator correction ... 7. Alarm contacts
Permanent indication errors caused by the ageing of the measuring system can
be ignored, as they only account for a fraction of the indication accuracy.

6. Indicator correction

GB
!
Note
Indicator corrections on gas-actuated thermometers with contacts may only be
carried out by the manufacturer or in adequately equipped workshops by
qualified persons.
T The micro-adjustment mechanism built into the pointer should only be
operated using a screwdriver, and only if the thermometer has been damaged
due to improper handling, severe shocks, during transport, etc.
T When correcting an indication error using the micro-adjustment mechanism,
a calibrated thermometer must be used for comparison.
T The thermometer can be opened by turning the bayonet-lock bezel of the
case counterclockwise using a strap wrench.

7. Alarm contacts

Gas-actuated thermometers can be equipped with magnetic snap-action,
sliding, inductive or electronic contacts (see data sheet AC 08.01).
In most cases, gas-actuated thermometers with contacts are used as two-
position controllers for on-off control or as three-position controllers for on-off-
on control with adjustable dead-band. In general thermometers' contacts can
only carry the operating current of an interposing control relay.
The contact mechanism consists of the red set pointer and the measured-value
pointer. The red set pointer can be adjusted using the supplied setting tool.
The measured-value pointer in a magnetic snap-action contact mechanism
consists of a pair of drag pointers, which are held against the red set pointer by
springs and is opened and closed at the set value by means of an operating pin
on the measured-value pointer.
8
Any interference with or modification to the instrument
will invalidate the warranty!
WIKA Operating instructions gas actuated thermometers