EW0826A2_en - rev. A
Oxygen detectors
–
URS20SI
05/10/2020
Gas detection systems for industrial environments
4/8
Electrical Installation
Terminal board and
electrical connections
Cabling:
Configuration:
4…20mA Output
reference selection:
4...20mA signal
operating mode
configuration:
Setting threshold limit
values:
CAUTION:
Make the area safe and make sure that the device power supply is
off before cabling and configuration operations.
Install the sensor in compliance with laws in force.
1“ NPT cable glands are used for cable entry.
Ground the sensor using the internal grounding system.
Relay card
(on connector
CN3)
Terminal Board TB1
12…24Vdc
+
-
4…20mA
-
+
JP2 jumper circuit Sensor card
S1 DIP switch
CN4 connector for
Handheld terminal
Depending on the connecting distance, use at least 3-core cable, min. diameter
0.75mm
2
up to 100m, 1mm
2
up to 200m, 1.5mm
2
up to 500m.
Use shielded cable where there is a risk of electromagnetic interference.
If a relay card is used, use multi-core cable suitable for the number of connections.
Make sure that the cable sheath is no larger than the diameter of the cable gland.
Default set
tings of the sensor are shown in the “Technical Specifications” chapter.
In order to change the default settings, switch off the power supply, input the new
settings at the JP2 jumper circuit or at the S1 DIP switch as shown in the diagram,
then power-up again; in particular:
The default setting for the 4-20mA signal is the negative power signal. Output
reference selection should be made by JP2 triple of jumpers; to change this setting,
operator has to move
JP2
jumpers as shown in the figure:
Caution: if the default settings are changed,
the connections on the
TB1
terminal board will
be inverted.
Ref. at
-
(default) Ref. at
+
To set the operating mode of the 4...20mA signal, it is necessary to use the 5th selector
of the DIP switch at
S1
; in particular:
Proportional Threshold mode
To set the threshold limit values of the optional relay card, or of the threshold operating
mode of the 4...20mA signal, it is necessary to use the last selector of the DIP switch
at
S1
(ignore the first four selectors); in particular, the thresholds, given in percentage
of O
2
, will be:
(S1.8 = OFF, default):
Pre-alarm
1
st
threshold alarm
2
nd
threshold alarm
O
2
excess
23% O
2
25% O
2
27% O
2
O
2
deficiency
19% O
2
17% O
2
15% O
2
(S1.8 = ON):
Pre-alarm
1
st
threshold alarm
2
nd
threshold alarm
22% O
2
23% O
2
24% O
2
20% O
2
19% O
2
18% O
2
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
Connection slot
for relay card
