The P890/P892 remote I/O processors provide a direct interface between 984 PLC and 800 series I/O. Both modules include an integrated power supply that supplies 3 amps of power to adjacent 800 series I/O modules. In addition, the P892 processor provides two half duplex ASCII ports.

The P890/P892 processor is mounted directly into a primary 19- or 27-inch 800 series I/O housing (H819/H827-209). The connection between the processor and the I/O modules is made through the housing backplane. The remote I/O system coaxial cabling provides the communications path between the P890/P892 processor and the RIO Head.

The P890/P892 processors are compatible with all programmable controllers that support the S908 remote I/O system. The P890/P892 processors are compatible with all 800 Series I/O modules: discrete, analog, register and intelligent. The actual number of remote I/O drops and I/O points per drop supported depends on the controller size.

The P890/P892 processors support a single remote I/O cable configuration. Cable runs from the 984 controller through taps that have drop cables to the P89X remote interfaces.

The P890/P892 processor power supply supports two separate power sources, 115/230 Vac and 24 Vdc. The AC power source is switch selectable between 115 V and 230 V settings. The top ON/OFF switch controls the AC power and the bottom ON/OFF switch controls the 24 Vdc source. Either source can be used to power the P890/P892. The 24 Vdc can be used as a backup power source to the 115/230 Vac. The single slot P890/P892 can provide a maximum of 3 amps to power 800 series I/O modules. For systems needing more power, expander power supplies should be inserted in the next I/O housing.