Johnson Controls IOM3721 Installation Manual page 5

SA/FC bus terminal block
An IOM can be connected to an SA bus or an FC bus,
but not to both buses simultaneously. The SA/FC
bus terminal block is a removable, 4-terminal plug
that fits into a board-mounted jack.
When connecting the IOM to an FC bus, wire the
bus terminal block plugs on the expansion module,
and the other controllers and expansion modules
in a daisy-chain configuration using 3-wire twisted,
shielded cable as shown in the following figure.
Figure 4: FC bus terminal block wiring
When connecting the IOM to an SA bus, wire the bus
terminal block plugs on the expansion module and
other SA bus devices in a daisy-chain configuration
using 4-wire twisted, shielded cable as shown in
Figure 5.
Figure 5: SA bus terminal block wiring
Note: The SA PWR/SHLD terminal does not
supply 15 VDC. The SA PWR/SHLD terminal
is isolated and can be used to connect (daisy
chain) the 15 VDC power leads on the SA bus
(Figure 5), or the cable shields on the FC bus
(Figure 4). The SA bus supervisor supplies 15
VDC to devices on the SA bus requiring power.
SA/FC bus Port
The SA/FC bus port on the front of the controller
is an RJ-12, 6-position modular jack that provides
a connection for devices on the SA bus, a Wireless
Commissioning Converter, a ZFR/ZFR Pro Wireless
Router (depending on which bus the controller is
operating on).
The SA/FC bus port is connected internally to the
SA/FC bus terminal block. See Table 3 for more
information. The SA/FC bus port pin assignment is
shown in Figure 6.
Figure 6: Pin number assignments for sensor, SA
bus and FC bus ports on Controllers
Supply power terminal block
The 24 VAC supply power terminal block is a gray,
removable, 3-terminal plug that fits into a board-
mounted jack on the top right of the expansion
module.
Wire the 24 VAC supply power wires from the
transformer to the HOT and COM terminals on the
terminal plug as shown in Figure 7. The middle
terminal on the supply power terminal block is not
used.
IOM3721 Expansion Input/Output Module Installation Guide 5