Rockwell Automation MDO16FNS 16-Channel Digital Output Module 120Vac/dc - Manual (Page 7)

MDO16FNS October 2005 – Issue 4 7
Triguard SC300E MDO16FNS 16-Channel D/O Module 120Vac/dc
Figure 2-3 Field output connector J2 pinouts
Connector J3 pin 1c is connected to earth.
All other pins on J3 are connected to field supply return.
THEORY OF OPERATION
In accordance with TMR practice, channel output command information from the MPP follows
three identical paths through the MDO16FNS (see Figure 2-4 ), each path at the command of
its own microcontroller in the common interface. In order to minimise the number of data
connections across the 1kV system-to-field barrier, the channel data are converted to serial
form before entering the module from the common interface. In this manner 16 output channels
can be served by just three paths instead of 48.
The three data streams are each applied to opto-isolators which mark the interface between
the system and field sides of the circuit and provide a system-to-field channel isolation of 1kV.