7 Fault diagnosis table
LED indicator/fault pattern /
LED indicator/fault pattern
Cause /
Cause
Measures /
Measures
Green LED does not light up /
Green LED does not light up
No voltage or voltage below
the limit values /
No voltage or voltage below
the limit values
Check the power supply,
check all electrical connecti‐
ons (cables and plug connecti‐
ons) /
Check the power supply,
check all electrical connecti‐
ons (cables and plug connecti‐
ons)
Green LED does not light up /
Green LED does not light up
Voltage interruptions /
Voltage interruptions
Ensure there is a stable power
supply without interruptions /
Ensure there is a stable power
supply without interruptions
Green LED does not light up /
Green LED does not light up
Sensor is faulty /
Sensor is faulty
If the power supply is OK, re‐
place the sensor /
If the power supply is OK, re‐
place the sensor
WT(B)23-2: Yellow LED fla‐
shes /
WT(B)23-2: Yellow LED flashes
Sensor is still ready for opera‐
tion, but the operating conditi‐
ons are not ideal /
Sensor is still ready for opera‐
tion, but the operating conditi‐
ons are not ideal
Check the operating conditi‐
ons: Fully align the beam of
light (light spot) with the re‐
flector. / Clean the optical sur‐
faces (sensor and reflector). /
Readjust the sensitivity
(teach-in) / Reflector is not
suitable for the application in
question (we recommend only
using SICK reflectors) / Check
sensing range and adjust if
necessary; see graphic H. /
Distance between the sensor
and the reflector is too long /
H. /
Check the operating conditi‐
ons: Fully align the beam of
light (light spot) with the re‐
flector. / Clean the optical sur‐
faces (sensor and reflector). /
Readjust the sensitivity
(teach-in) / Reflector is not
suitable for the application in
question (we recommend only
using SICK reflectors) / Check
sensing range and adjust if
necessary; see graphic H. /
Distance between the sensor
and the reflector is too long /
H.
WTE23-2: Yellow LED flashes
(only briefly) /
WTE23-2: Yellow LED flashes
(only briefly)
Teach-in mode /
Teach-in mode
Check the teach-in mode /
Check the teach-in mode
Signal interruptions when ob‐
ject is detected /
Signal interruptions when ob‐
ject is detected
Depolarizing property of the
object surface (e.g., tape), re‐
flection /
Reduce sensitivity or change
the position of the sensor /
Reduce sensitivity or change
the position of the sensor
FAULT DIAGNOSIS TABLE 7
8015975.YHN1 | SICK
Subject to change without notice
5