10
INM MTL 130-0126 Rev 13
NOTE
For all installations the cable length connecting the sensor to the instrument must not
exceed 30 metres.
Figure 5 shows details of connections for installations where the control unit is mounted in a
non-hazardous environment but the sensor has to be located in a hazardous area, i.e. where
there is a known risk of a potentially explosive atmosphere being encountered.
Figure 6 shows the internal wiring connections for a “flameproof” Ex d enclosure where the
electronic control unit also needs to be mounted in the hazardous area.
3.7.2 Control/display unit connections
The connections for the control/display unit are located on the rear of the case - except when it is
mounted in the flameproof box, in which case the connections are provided at DIN-rail mounted
terminals.
WARNING
AC mains power (115 or 230V AC) is required to power the K1650 control/
display unit. Ensure that supplies are isolated at some external point before
working on connections to the unit.
CAUTION
Check the supply voltage rating of the control unit before connecting it to the AC power
source. The unit will be damaged by the application of a voltage exceeding the
specified range.
Figure 7 -
Connections at rear of control/display unit
Figure 7 shows the connections provided at the rear of the K1650, including the 4/20mA analogue
output (terminals 19 & 20), the alarm outputs (terminals 1-12) and the AC power inputs (16-18).
AC power signals should be kept apart from the input signal cabling, as much as possible, to avoid
potential interference and any hazard from the high voltage cabling.
In normal operation (i.e a non-alarm state) the alarm relays are energised, providing continuity
between the ‘C’ and ‘NC’ terminals.
continued
16
17
18
19
20
N
-
E
L
+
4/20mA
Output
C
6
5
4
3
2
1
NC
NC
NO
NO
C
120-0384-2
C
12
11
10
9
8
7
NC
NC
NO
NO
C
H
2
in CO
2
/
Range Alarm
H
2
in Air /
Alarm 2
H
2
in Air /
Alarm 1
120-0404-5
CO in Air /
2
Alarm
Range / Fault
