User guide

Relay Output Modules (T7446L, H)
2 Industrial Control Services
Module Operation
A block diagram of a typical relay output module is shown in
Figure 1 .
The processor modules send triplicated write data commands
to the output module over the I/O Safetybus. The processors’
addressing data and data write commands are voted by the
module (preventing I/O Safetybus failures upstream from the
module from affecting module operatio n). The voted result is
then passed to the I/O bus interface logic.
Figure 1 . Block Diagram of a Relay Output Module.
The voted output data from the I/O bus interface logic is then
used to drive the output circuits. Logic output drive signals
energize the coils of relays mounted on the printed circuit
board. Relay contacts provide dry - contact switching of load
devices.
When the output is logically turned on, the relay coil is
energized (closing the N.O. contact), and when the output is