Rockwell Automation T8842 Trusted Versatile FTA - Manual (Page 11)

Trusted
TM
Versatile FTA T8842
Issue 8 Aug 12 PD-T8842 11
Digital Inputs (Line Monitored)
Figure 5 shows a channel configured to accept line monitored digital input signals.
Figure 5 Digital Inputs (Line Monitored without power)
The configuration shown above enables line monitored digital input devices to be interfaced to the
Trusted
TM TMR Zone Interface module (or a TMR Digital Input module). The channel is configured by
fitting a 315mA fuse in position B, which provides circuit protection. Power for the field loop is derived
from the dual 24Vdc source. The input signal is returned via a 2A fuse in position A, which acts as a
link.
For inputs without line monitoring components or using zener diodes, to a Zone Interface or Valve
Monitor module, a 1K 0.6W resistor is required in position A. This is because the module requires an
impedance to allow internal testing. Note that this will change the voltages seen by the module.
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
2A
315 mA