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INM MTL SUM5 Rev 1
4.7 Power and heat considerations
The power consumption for a single module base i.e. channel will depend upon the
voltage used to supply the carrier and the mode in which the UI module is used. The
table below gives a guide to the current drawn and the power dissipation, per channel,
for the modes indicated. These figures may be used as a guide when calculating the
total heat generation for each installation area and so determine any need for additional
ventilation or active heat removal (fans).
AI, AO, DI modes
DO mode
Current at 24V supply
45mA (typ.)
100mA (typ.)
Power dissipation
< 500mW
1W
The optimum orientation for carriers when determining heat dissipation, and for ambient
temperatures in excess of 60°C, is to have the carrier mounted in a ‘landscape’ fashion
with the channels numbering across horizontally. In situations when dissipation is not so
critical or when forced cooling is provided, the carriers can be mounted with channels
being ‘stacked’ one above each other in a ‘portrait’ orientation, as illustrated below in
Figure 4.6.
Figure 4.6
- A mounting suggestion to optimise wiring segregation
(for maximum I/O density a 3 column configuration may be used)
