Zero Adjustment - WIKA SB15 Manual De Instrucciones

5. Commissioning, operation
Temperature checks using thermometers with probes assembled with thermowells can,
in many cases, only result in a reference temperature at the test item, due to permanent
heat dissipation caused by the thermowell. In temperature applications fitted with
static checking thermometers (e.g. pipeline systems), permanent offsets in reference
temperatures can also be caused by the measuring path.
Ambient temperatures around the indicator case which differ substantially from room
temperature can lead to steady indication errors with constant ambient temperatures and
to varying indication errors with fluctuating ambient temperatures.

5.6 Zero adjustment

A zero adjustment may only be carried out by the manufacturer or in adequately equipped
workshops by qualified personnel.
5.7 Unlocking and restoring the operating state
After exceeding the factory-set limit temperature, a switching operation of the SB15 and
SW15 is triggered. Thus, the plant is separated from the energy supply until the medium
to be monitored is in a safe operating condition again. The temperature of the medium to
be monitored must significantly fall below the preset limit temperature before the safety
temperature limiter or safety temperature monitor is switched back by unlocking.
With safety temperature limiter model SB15
■
1. Have the screwdriver ready.
2. Remove the plug screw at the front side of the instrument (in the centre of the window)
using a suitable screwdriver.
3. Rotate the pointer shaft counterclockwise using a suitable screwdriver until a noticea-
ble resistance has been overcome.
4. Place the plug screw again and tighten it by hand.
Note: If the SB15 cannot be unlocked, then
a) check whether the displayed temperature is at least 3 % of the scale range below the
switch point.
b) check the measuring line for cable break.
With safety temperature monitor model SW15
■
The SW15 switches back automatically as soon as the temperature of the medium to be
monitored moves to the predefined temperature range again.
Note: If the SW15 cannot be unlocked automatically, then
a) check whether the displayed temperature is at least 3 % of the scale range below the
switch point.
b) check the measuring line for cable break.
WIKA operating instructions models SB15, SW15
EN
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