Rockwell Automation T7903 ICS Regent+Plus I/O Termination Assembly (ITA) - Manual (Page 22)

I/O Termination Assembly
2 2
Industrial Control Services
A p p e n d i x C - Single Ended, Current
Limiting, Field Loop With Dioded Power
Protection (24V)
YTMR790112 (Right Hand Varelco Connector)
YTMR790212 (Left Hand Varelco Connector)
YTMR790312 (Screw Terminal Connector)
The Single Ended, Current Limiting, Field Loop ITA provides the facility
to provide a method for supplying a common feed/return path to field
devices on a per module basis, as shown below. The ITA has a 2k2,
5%, 1.6W resistor in the common feed/return path. The resistor is
designed to blow open circuit if too much power is dissipated through
it.
The Single ended, Current Limiting Field Loop ITA should NOT be
used with the T7420 Analog Input Module.
The single ended signal is fed from the I/O chassis to the ITA. The ITA
provides a common dioded supply which is tracked out on the ITA to
provide each single ended signal with a current limited feed/return
supply path. The overall maximum current of the ITA should not
exceed 2.5A total if current is supplied via diodes or 16A total if
supplied via J10.
Single ended I/O modules have 16 field circuits and one ITA will be
required for each module.
The connector idents are shown on the legend on the ITA.
The block diagram below shows typical connection of the module to
the field device.