Gebrauchsanweisung / Instructions for Use - SCHMIDT
®
Flow Sensor SS 20.225
20
The measuring range of the medium temperature T
M
is specified from
-
20 … +70 °C (refer above, right grafic) and also output linearly.
o Medium temperature below -20 °C
Both signal outputs go to error signal (0 V).
o Medium temperature above +70 °C (at approx. 75 °C)
15
The signal output for w
N
switches to error (0 V).
The signal output for T
M
switches directly to the maximum output
value of 11 V.
o Note regarding commissioning:
Normally the temperature output provides approx. 4.5 V because of
the typical prevailing room temperature of 20 °C.
6 Commissioning
Before switching on the
SCHMIDT
®
Flow Sensor SS 20.225
, it must be
checked if it is installed correctly, both mechanically and electrically.
Correct measuring values can be expected after approx. 20 seconds if the
sensor probe already has the medium temperature. Otherwise, the pro-
cess will last longer until the probe has reached the medium temperature.
During this initialisation phase the green LED flashes (2 Hz).
As soon as the green LED lights up continuously, the sensor is ready for
operation.
Conversely, if the sensor detects an internal defect, the green LED
switches off (or
hasn’t turned on at all) and the red LED flashes (2 Hz).
This also applies in the event that a defect occurs in the course of subse-
quent operation.
7 Information concerning operation
Ambient conditions medium
Soiling or other gratings on the probe cause distortions of meas-
urement results.
Therefore, the sensor must be checked for soiling at regular inter-
vals and cleaned if necessary.
(Condensating) liquid on the measuring probe causes serious
measurement distortions.
After drying the correct measuring function is restored.
15
The switching hysteresis for the decision threshold is approx. 2 K
