Rockwell Automation T7454 ICS Regent+Plus AC Isolated Digital Output Module - Manual (Page 2)

AC Isolated Digital Output Module (T7454)
2
Industrial Control Services
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 operation). The voted result is
then passed to the I/O bus interface logic.
Figure 1. Block Diagram of 110 VAC Isolated Digital Output Module.
The voted output data from the I/O bus interface logic is then
used to drive the output circuits. Zero crossing turn-on
TRIAC drivers are used to convert the logic level output drive
signals to switch 110 VAC power to load devices.
When the output is logically turned on, the field device is
energized, and when the output is logically turned off, the
field device is de-energized.
Optical isolation between the module’s logic and field circuits
provides logic-to-field isolation — protecting the output
module from field signal over voltages, transients, and other
electrical disturbances. It also provides a safety barrier
between the primary field voltages and user accessible
circuits. Additionally each output is isolated from the other