e unit should be installed stably and in a vibration-free manner, according to
the recommended installation method.
Pipe-enclosure units should be fixed to a mounting plate with a hole of
∅ 31 mm using the nuts supplied to nold the plate in the middle. Units with flat
3. INSTALLATION
The unit should be installed stably and in a vibration-free manner, according to
the recommended installation method.
Pipe-enclosure units should be fixed to a mounting plate with a hole of
∅ 31 mm using the nuts supplied to nold the plate in the middle. Units with flat
enclosure can be mounted to the wall or any flat surface laid on its backside,
using the four nuts. Cables should be free of tension and LEDs should be
visible.
In case of limited space, the path of the ultrasonic beam may be redirected by
a metal sheet as below (Figure1).
diverting sheet UR/UT-200.
A + B > x m in
A
B
Surface detected
Figure 1
Redirection of the ultrasonic beam using a reflective surface
Sensor
Surface detected
Indefinite half sheet
Target
Xt ∅dt e't e''t
U -21
Curve of disturbance
dt = 13 [mm]
0 20 40 60 80 100 Xt [cm]
e t [cm]
20
10
0
U -26
d t = 50 80 [mm]
0 1 2 3 4 5 6 Xt [m]
e t
[m]
0,6
0,4
0,2
0
Curve of disturbance
Figure 2
Limits of disturbance and sensing
Bmin 1.5 Bmin
U -21
B [m] min
U -26
0.25
0.75
Figure 3
Minimum distance of units working parallel next to each other
Figure 2 shows the distance (e’t) within which the unit senses the target as well
as the distance (e”t) outside of which disturbing objects do not disturb the
operation of the unit. Units with the same frequency may mutually disturb each
other as sent or reflected ultrasound may reach the other unit. To avoid such
interference, units with parallel axes should be installed outside of the minimum
distances as per Figure 3. Greater minimum distances might be required for
applications with targets with round reflecting surfaces (like pipes) that involve
side reflections.
4. WIRING
Wiring should be carried out in accordance with Figure 4 and Figure 5 taking
into consideration the colour of the wires as per Table 1.
GND
B A
+Us
SW / OUT
PRG
GND
shielding
+10.8...30V DC
+
Rt
+Us
SW / OUT
NPN
switch
PNP
switch
or
analogue
PRG
GND
shielding
+
+10.8...30V DC
GND
Figure 4
Wiring during programming
Figure 5
Wiring during operation
Type Cable Colour*
+US brown
IUOT or UOUT green
PRG white
GND yellow
UT-21-4
UT-22-4
shielding blue
+US brown
SW green
PRG white
GND yellow
UR-23-4
UR-24-4
shielding blue
* The grey cable with isolated ending is only for service purposes
Table 1
Cable colours
5. COMMISSIONING, OPERATION AND PROGRAMMING
5.1 COMMISIONING, OPERATION
Following the power up, the unit will run a self-test routine for 5 seconds.
During the self-test all three LEDs are lit. In the event of a failure all the LEDs
will blink at the same rate.
Interpretation of the LED states during proper operation:
Green: Blinks at the rate of the measurement.
(lights continuously at high frequencies)
Yellow: Lights up continuously in the case of valid echo.
Red: Lights up if the unit senses a disturbance signal within the minimum
measuring range (e.g. bad installation) or if the target is too close.
In this case an error will be indicated by the output
The UR-23-4 devices compare the measured distance with the two
pre-programmed (XA and XB) distances and switch in accordance with Figure 6.
XA < X B
XA XB
closed
open
XA > X B
XA XB distance
closed
open
distance
Figure 6
Transfer characteristic of units with switch output