12
2.4 Electrical connections
All connections are made via the screw terminal block mounted on the
amplifier PCB in the junction box. The terminals are marked ‘+’ and ‘’
and correct polarity should be observed when connecting the detector to
control equipment. This version of
Xgard
is a 420 mA current sink
device, and requires a dc supply of 830 V.
Note: The internal grounding terminal (see diagram 4) shall be used as the
grounding means of the
Xgard
gas detector. The external grounding
terminal ( see diagram 4) is only a supplemental bonding connection, and
is only to be used where local authorities permit or require such a
connection. To limit radio interference, the junction box and cable armour
should be grounded (earthed) at the control panel. Ensure the earth
connection is provided in a safe area only, so as to avoid earth loops and
maintain I. S. certification.
Diagram 5:
Xgard
Type 1 electrical connections
2. Installation
Xgard Type 1
Pepperl & Fuchs
Z715 / Z728
1
2
8
7
SIG
MTL
715+ / 728+
3
4
1
2
SIG
1
3
8
7
Pepperl & Fuchs
1211
2
1
12
11
MTL
5041
1314
SIG
SIG
KF D2-CR-Exl.30200
Pepperl & Fuchs
and
MTL
galvanic isolators
Xgard Type 1 PCB
Control Panel
I.S. Earth
I.S. Earth
Earth
Earth
Control Panel
SAFE AREA
HAZARDOUS AREA
Pepperl & Fuchs and MTL Zener barriers
Xgard Type 1 PCB
24V dc
Supply
24V dc
Supply
SAFE AREA
HAZARDOUS AREA
