Distance
Output current
in mA
20.5
20.0
4.0
3.5
1
2
Figure 12: Normalized measurement function (decreasing behavior)
1
Reference point 4 mA
2
Reference point 20 mA
3.8.2
Alarm function - hold
With the “Hold” function, the last valid measured value is held in the event of an
error. This process repeats until it is once again possible to run a measurement. This
function can be used instead of the clamp function and also affects decision and
measurement functions, however with this setting a fault condition in the device is
not immediately detected. The function may therefore only conditionally be used for
safety-related purposes.
1
2
1
Figure 13: Hold alarm function
1
Measurement successful or measured value determined: Output measured values
2
No measured value determined: Output substitute value
3.8.3
Signal level and signal quality
Signal level (“Level”)
The signal level corresponds to the amount of reflected light received by the receiver
optics of the device. This is a dimensionless value. It essentially depends on the
distance from the measuring object and on the surface of the measuring object (color,
roughness/reflectivity, angle to the optical axis). To enable the device to measure the
distance correctly, the signal level must not drop below a certain value. This value
depends on the selected speed.
You can configure the Q1 or Q2 output for the signal level warning (OWS). The level
can be adjusted within the range 0 … 65535. If the signal exceeds or falls below the
configured level, the output is connected. Hysteresis cannot be configured. The output
behavior can be inverted.
Likewise, the status of the signal level warning can be provided via the status bits (bit 0
or bit 1) as part of the process data (process data format 0) via the IO-Link interface.
Depending on the application, the setting must always be defined by the system inte‐
grator. When using the signal level warning (OWS), we recommend first performing a
measurement of a reference object with known and constant optical properties.
PRODUCT DESCRIPTION
3
8027663//2022-08-04 | SICK
O P E R A T I N G I N S T R U C T I O N S | DT35S
21
Subject to change without notice