Johnson Controls IOM2721, Installation Manual, Page: 2 / 18

Figure 1: IOM2721 physical features
Table 1: IOM2721 physical features callouts and
descriptions
Physical feature: description and references
1 Analog Outputs (AOs) Terminal Block (see Table 2)
2 Mounting Clip
3 Device Address DIP Switch Block (see )
4
24 VAC, Class 2 Supply Power Terminal Block (see Supply
power terminal block )
5
Cover Lift Tab (see Removing the expansion module
cover )
6
Sensor Actuator (SA) Bus/Field Controller (FC) Bus
Terminal Block (see SA/FC bus terminal block )
7
End-of-Line (EOL) Termination Switch (see Setting the
End-of-Line (EOL) Switch )
8 Universal Inputs (UIs) Terminal Block (see Table 2)
9 LED Status Indicators (see Table 8)
Mounting
Observe the following guidelines when mounting an
expansion module:
• Ensure the mounting surface can support the
expansion module, DIN rail, and any user-supplied
enclosure.
• Mount the expansion module horizontally on 35 mm
DIN rail whenever possible.
• Mount the expansion module in the proper mounting
position (Figure 2).
• Mount the expansion module on a hard, even surface
whenever possible in wall-mount applications.
• Use shims or washers to mount the expansion module
securely and evenly on the mounting surface.
• Mount the expansion module in an area free of
corrosive vapors and observe the Ambient Conditions
requirements in Table 9.
• Provide for sufficient space around the expansion
module for cable and wire connections for easy cover
removal and good ventilation through the expansion
module (50 mm [2 in.] minimum on the top, bottom,
and front of the expansion module).
• Do not mount the expansion module on surfaces prone
to vibration, such as duct work.
• Do not mount the expansion module in areas where
electromagnetic emissions from other devices or wiring
can interfere with expansion module communication.
Observe these additional guidelines when mounting an
expansion module in a panel or enclosure:
• Mount the expansion module so that the enclosure
walls do not obstruct cover removal or ventilation
through the expansion module.
• Mount the expansion module so that the power
transformer and other devices do not radiate excessive
heat to the expansion module.
• Do not install the expansion module in an airtight
enclosure.
Figure 2: Mounting positions
DIN rail mount applications
About this task:
IOM2721 Input/Output Module Installation Guide 2