Location Of Modules In The Plc Racks - GE 90-30 PLC Series Installation And Hardware Manual

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Location of Modules in the PLC Racks

There are several factors to consider when laying out your PLC racks.
12-18 Series 90-30 PLC Installation and Hardware Manual – August 2002
Locate PLC racks at a convenient level that allows technicians reasonable access for
maintaining the system.
Route sensitive input wires away from electrically noisy wires such as discrete output and AC
wiring. This can be facilitated by grouping I/O modules to keep Output modules separated
from sensitive Input modules.
The PLC racks each require a 4" clearance space on all four sides (6 inches on the right end if
using I/O Bus Expansion Cables) to ensure adequate ventilation/cooling. See the "Baseplates"
chapter for baseplate size and clearance requirement information.
Location restrictions - Although most modules can be located in any type of baseplate, a few
of the Option modules (PCM, ADC, CMM, SLP) will only work in a CPU baseplate. The next
figure identifies where you can locate the modules in your system.
Power Supply capacity - Since some modules draw considerably more power than others, it is
possible to overload the power supply by placing many of the modules requiring higher power
in one rack. Therefore, before finalizing your rack layout you should calculate the power
supply loading to ensure that you will not overload the power supply. See the section
"Calculating Power Supply Loading."
Noise Reduction - Group I/O modules to keep Output modules separated from sensitive Input
modules. This facilitates keeping noisy wiring separated from sensitive wiring, as
recommended in a previous section.
GFK-0356Q