Rockwell Automation T8842 Trusted Versatile FTA - Manual (Page 9)

Trusted
TM
Versatile FTA T8842
Issue 8 Aug 12 PD-T8842 9
Figure 3 Power Group Configuration
The diagram above shows the full wiring for one power group of eight channels. This circuit is repeated
for each of the five power groups.
In the diagram, odd-numbered resistors are precision 250 ohms and even numbered resistors are
power 250 ohms. Links E and F cannot be fitted simultaneously, and links C and D cannot be fitted
simultaneously.
Note that 24V field power is required for a Zone Interface Module even if all channels are configured as
volt-free inputs. This may be connected via the plug at the chassis end of the cable to a T8290 or
T8297 distribution unit (for cables without power wires) or at the VFTA (for integral power cables).
Each power group is supplied from dual 24Vdc feeds which are ‘commoned’ via diodes on the VFTA.
The supply is then fed to each channel within the group. The feeds are rated at 3 amps maximum and
are designed for input circuit power.
The following sub-paragraphs detail each type of input or output configuration.