Module operation – Rockwell Automation T3441A ICS Regent DC Digital Output Module 24 VDC User Manual
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DC Digital Output Module (T3441A)
 
2  
Industrial Control Services
Module Operation
A block diagram of a typical 24 VDC digital 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 operation). The voted result is 
then passed to the I/O bus interface logic. 
Figure 1. Block Diagram of 24 VDC Digital Output Module.
The voted output data from the I/O bus interface logic is then 
used to drive the output circuits. Power MOSFETs are used 
on the outputs to convert the logic level output drive signals 
to switch 24 VDC power to load devices. These output circuits 
provide a very low on state voltage drop and low off state 
leakage.