EsiWelma Srl
URS20SL_en.doc - rev. 0
Oxygen detectors – URS20SL
20/10/2010
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.
The cable gland provided on the housing is used for cable entry.
Ground the sensor using the internal grounding system.
Ground connection
Terminal board TB1
12…24Vdc
+
-
4…20mA
-
+
JP2 jumper circuit
Dip-Switch S1
CN4 connection 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.
Default settings 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
Relay card
Sensor card
Connection
slot for relay
card
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
