Instruction manual

14
INM4840-5 Nov 2007
14
4.11.3 Power supply connections
All of the BPxH backplanes have provision for dual, redundant 24V
dc power supplies. The supplies have individual, screw-terminal,
plug-in connectors and two LEDs are provided on the backplane
to indicate which supplies are operational. A series diode in each
supply input means that the higher of the two voltage supplies is used
and there is an automatic switch-over of supplies if one fails.
The BPMH16 backplane has three monitor points that sense the two
individual power supply voltages and also the final output voltage
after the series diodes. These are provided on the Elco multipin
connector (see Table 4.1) via 10kΩ series protective resistors to
provide the process system with status indications.
Connect each of the two power supply connectors to the independent
supply sources according to the terminal assignments shown in
Figure 4.20.
The maximum wire size is 2.5mm
2
(12AWG).
Plug the connectors into the sockets on the backplanes.
The backplane has two fuses: FS1 protects the isolators and FS2
protects the MTL4841 and MTL4842 modules. Ratings for these
fuses are:
FS1: 2A (MTL fuse kit FUS16)
FS2: 250mA (MTL fuse kit FUS02)
4.11.4. Safe area – ring-mained power supplies
A “ring main” system can be used to distribute power to the
backplanes. This permits individual backplanes to be taken out of
service without affecting supplies to other backplanes. Two or more
backplanes can be removed, provided they are neighbours, without
disrupting the supply to other backplanes. Make the connections as
shown in Figure 4.21.
Note: Backplanes can be ring-mained providing the
maximum circuit current does not exceed 12A. Wire
sizes up to 2.5mm
2
(12AWG) can be used and should
be chosen according to load and voltage drop.
1 2 3 4 5 6 7 8 9 10
11
12 13 14 15 16
+
+
+
1 2 3 4 5 6 7 8 9 10
11
12 13 14 15 16
Figure 4.19 - Screw-clamp terminal pin assignments
+
+
_
1
2
Primary
power
supply
Secondary
power
supply
_
PWR PWR
0 V
0 V
0V
PSU
+
PWR1
A secondary supply
can be connected
in the same
configuration to
PWR2 connector
8 9 10 11 12 13 14 15 16 8 9 10 11 12 13 14 15 16
8 9 10 11 12 13 14 15 16
Figure 4.20 - Pin assignments - safe area power supply
Figure 4.21 - Supply circuitry for interconnecting backplanes
4.11.2 BPSH16 & BPSH16-32 - screw-clamp terminals
In the case of the screw-clamp terminal backplanes, each module
position is provided with a 2-way split-level terminal block for safe
area signals.
The connection procedure is:-
Check pin assignments for the MTL4041B/P as per Figure 4.17.
Check pin assignments for the MTL4046P as Figure 4.18
Make the appropriate connections to the safe-area terminals in
accordance with Table 4.2 and Figure 4.19.
Maximum wire gauge is 2.5mm
2
(12 AWG) and wire entry for each
terminal is from side of block.
Notes
1. To pass HART data, input terminal 11 or 12 must be referenced
to the backplane power supply.
2. Module pins 9 and 12 are linked on the backplane.
Table 4.2 - Screw terminal connections for MTL4041B/P and
MTL4046P
Safe area
terminal
BPMH16 module
and pin ident.
Safe area
terminal
BPMH16 module
and pin ident.
1+ Module 1 9 & 12 9+ Module 9 9 & 12
1
11
9
11
2+ Module 2 9 & 12 10+ Module 10 9 & 12
2
11
10
11
3+ Module 3 9 & 12 11+ Module 11 9 & 12
3
11
11
11
4+ Module 4 9 & 12 12+ Module 12 9 & 12
4
11
12
11
5+ Module 5 9 & 12 13+ Module 13 9 & 12
5
11
13
11
6+ Module 6 9 & 12 14+ Module 14 9 & 12
6
11
14
11
7+ Module 7 9 & 12 15+ Module 15 9 & 12
7
11
15
11
8+ Module 8 9 & 12 16+ Module 16 9 & 12
8
11
16
11