Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 12 Page 53 of 265
3.12 Maximum Number of I/O Cards and Intelligent Detector Backplanes
The total number of I/O cards and Intelligent Detector Backplanes that can be fitted
to the ST900 ELV Controller is limited by the current capability of the power supply
fitted to the LPU. See Table 9 for details on the mix of cards that can be fitted to the
controller.
Number Of
Backplanes
Required
Maximum
Number Of
I/O Cards
Maximum
Number Of
Loops
Maximum
Number Of
Inputs
Maximum
Number Of
Outputs
0 8 0 192 128
1 8 16 192 128
2 8 32 192 128
3 7 48 168 112
4 7 64 168 112
5 7 80 168 112
6 6 96 144 96
7 6 112 144 96
8 6 128 144 96
9 5 144 120 80
10 5 160 120 80
11 4 176 96 64
12 3 192 72 48
13 2 208 48 32
14 1 224 24 16
15 0 240 0 0
Number Of
Backplanes
Required
Maximum
Number Of
I/O Cards
Maximum
Number Of
Loops
Maximum
Number Of
Inputs
Maximum
Number Of
Outputs
0 4 0 96 64
1 4 16 96 64
2 4 32 96 64
3 3 48 72 48
4 3 64 72 48
5 3 80 72 48
6 2 96 48 32
7 2 112 48 32
8 2 128 48 32
9 1 144 24 16
10 1 160 24 16
11 1 176 24 16
12 0 192 0 0
13 0 208 0 0
14 0 224 0 0
Table 9 – I/O Card and Detector Backplane (ST900 ELV)
Notes: Each I/O card draws a maximum of 150mA and each Backplane Controller draws a maximum
of 50mA. The total combination of I/O cards and Backplane Controller Cards must not draw more
than 1300mA (700mA if IRM/IMU fitted and powered from 24V DC). The maximum total number of
I/O cards and Backplane controller cards in a system cannot exceed 15. The addition of an SDE/SA
Without an IRM/IMU Card fitted.
If an IRM/IMU Card is fitted and powered from
the +24V DC Supply, then the power available
for the I/O Cards and Backplanes is reduced.