Rockwell Automation T8480 Trusted TMR Analogue Output Module - 40 Channel - Manual (Page 10)

Trusted
TM
Module T8480
Issue 13 Apr 10 PD-T8480 10
1.1. Output Field Termination Unit (OFTU)
The Output Field Termination Unit (OFTU) is the section of the I/O module that connects all three AO
FIUs to a single field interface. The OFTU provides the Group Fail-safe switches and passive
components necessary for signal conditioning, over-voltage protection, and EMI/RFI filtering. When
installed in a Trusted
TM Controller or Expander Chassis, the OFTU field connector interconnects to the
Field I/O Cable Assembly attached at the rear of the chassis.
The OFTU receives regulated power and drive signals from the HIU and provides magnetically isolated
power to each of the three AO FIU’s.
The SmartSlot link is passed from the HIU to the field connections via the OFTU. These signals go
directly to the field connector and maintain isolation from the I/O signals on the FTU. The SmartSlot
link is the intelligent connection between active and standby modules for co-ordination during module
replacement.
1.2. Analogue OUTPUT Field Interface Unit (AOFIU)
The Analogue Output Field Interface Unit (AOFIU) is the section of the module that contains the
specific circuits necessary to interface to the field I/O signals. Each module has three AO FIUs, one
per slice. For the TMR 24V dc Analogue Output Module, the AOFIU contains one slice of the output
driver circuit, for each of the 40 field outputs.
The AOFIU receives isolated power from the OFTU for logic. The AOFIU provides additional power
conditioning for the operational voltages required by the AOFIU circuitry. An isolated 6.25Mbit/sec
serial link connects each AOFIU to one of the HIU slices.
The AOFIU also measures a range of on-board “house-keeping” signals that assist in monitoring the
performance and operating conditions of the module. These signals include power supply voltages,
current consumption, on-board reference voltages, and board temperature.