Rockwell Automation 1747-L5xx SLC 500 Modular Hardware Style User Manual - Manual (Page 261)

261 Publication 1747-UM011G-EN-P - June 2008
Appendix
H
Calculating Heat Dissipation for the SLC 500
Control System
This appendix will assist you in calculating the heat dissipation of
your SLC 500 controller. It consists of:
• a definition of key term.
• a table and graph.
• an example heat dissipation calculation.
• a heat dissipation worksheet.
To select an enclosure see page 40.
Definition of Key Terms We use these terms throughout this appendix. Familiarize yourself
with them before proceeding further.
Watts per Point - maximum heat dissipation that can occur in each
field wiring point when energized.
Minimum Watts - amount of heat dissipation that can occur when
there is no field power present.
Total Watts - the watts per point plus the minimum watts (with all
points energized).
Calculating Module Heat
Dissipation To calculate the heat dissipation of your SLC controller you must
consider:
• the maximum heat dissipated (with field power applied) by the
processor, all I/O and specialty modules, and any peripheral
devices for each chassis.
• the heat dissipated by the power supply. This is determined by
the maximum load on the power supply of the processor, each
I/O and specialty module, peripheral device, and device
drawing power directly off the power supply via the POWER
OUT terminals.