Choosing A Slot In The Chassis - Allen-Bradley SLC 500 1746-NI4 Installation Instruction

10 SLC 500™ Analog I/O Modules
Switch Settings for the 1746-NIO4I, -NIO4V, -FIO4I, and
-FIO4V
The NIO4I and NIO4V have 2 individual switches labeled 1 and 2. These
switches control the input mode of channel 0 and 1. A switch in the ON position
configures the channel for current input. A switch in the OFF position configures
the channel for voltage input.
External Power Switch for the 1746-NO4I and -NO4V
The NO4I and NO4V analog output modules have an external 24V dc power
switch, SW1, which gives you the option of using an external power supply. In
the UP position, power is drawn from an external power source. In the DOWN
position, power is drawn from the backplane of the module. The switch is located
on the analog module board. Switch orientation is also provided on the nameplate
of the module.
24V dc
Power
Selector

Choosing a Slot in the Chassis

Two factors determine where the analog module should be located in the chassis:
ambient temperature and electrical noise. Consider the following conditions
when selecting a slot for an analog module. Position the module:
• in a slot away from an ac or high voltage dc modules
• in the chassis closest to the bottom of the enclosure where the SLC 500 system
is installed
• away from the chassis power supply if installed in a modular system
Publication 1746-IN008A-US-P
Current
1 2
Switch 1 = Channel 0
O
Switch 2 = Channel 1
N
Voltage
External
SW1
Backplane