An FX-PCX expansion module can be connected to a Sensor/Actuator (SA) bus or a Field Controller (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 FX-PCX 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 Figure 1.
When connecting the FX-PCX 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 2.