Rockwell Automation T8842 Trusted Versatile FTA - Manual (Page 8)

Trusted
TM
Versatile FTA T8842
Issue 8 Aug 12 PD-T8842 8
1. Description
The Trusted
TM
Versatile FTA T8842 provides termination for a maximum of 40 input or output channels
from various types of field devices. The input signals may be analogue (0-20mA) or digital, whilst
output signals are digital only with the T8448 Zone Interface Module. However, the Versatile FTA
T8842 may be used with the T8480 Analogue Output module using the Digital Output configuration
shown in this document.
The 40 channels are arranged in five power groups each comprising eight channels. Each channel
circuit includes two resistors.
High power 250R 7W 1% resistors to limit short circuit current
Precision 250R 0.25W 0.1% resistors to measure analogue field current
Each circuit contains a set of link positions and can be configured with the following components
supplied with the VFTA to enable the user to set the channel for the required input or output
configuration.
50mA plug-in TE5 series fuses to protect analogue current inputs
315mA plug-in TE5 series fuses to protect digital inputs
2A plug-in TE5 series fuses to protect digital outputs or act as low resistance links
The first channel of each power group may be configured as a power source for the other seven
channels of the group, to allow fire loops to be hard reset by the application.
The cable linking the 40 channels on the Trusted
TM
Module to the VFTA is terminated at five 10-way
connectors (TBG1 to TBG5). The dual 24Vdc power supplies are connected to the VFTA via five 4-way
connectors (TBFP1 to TBFP5). Forty 3-way connectors are used for the field loops (TB1 to TB40).
Figure 2 Layout for single channel showing all components
Field
Power
TBFPn
0V
Channel 1
B
Precision Resistor
Signal
A
0V
Field
Terminals
TBn
Signal
TBGn
Power Resistor
C
D
F
E
Fuse Field Power
3
2
1 1
2
3
4
m
2