Rockwell Automation T8141 Trusted Demonstration Unit - Manual (Page 10)

Trusted
TM
Demonstration Unit T8141
Issue 1 Feb 06 PD-T8141 10
3. Operation
The Digital Input switches operate inputs 1 to 20 as marked. Pushing the switch down connects the
input to 24V (logic 1) and pushing the switch up will allow the input to return to 0V (logic 0).
The Digital Output lamps indicate channels 1 to 20 as marked. They are designed for 24V operation
and are each fitted with 390R 2.5W resistors in parallel to increase the load above the line monitor
open-circuit threshold. For lamps 19 and 20, Field Fault switches 1 and 2 respectively will connect a
short circuit across the lamp if pressed down, for demonstration of line fault conditions.
The Analogue Input potentiometer knobs control channels 1 to 20 as marked. They are connected to
provide a potential divider to the analogue input. Each has a 27K 0.25W resistor connected from the
24V supply, in series with the 10K track of the potentiometer, to zero volts. The analogue input voltage
may be adjusted between the zero volt rail and approximately 6.5 volts, to simulate the full range of 0-
22mA inputs with over-range excess.
Figure 4 Analogue Input Connection
Two terminals (11 and 12) at the bottom of the 24Vdc fuse distribution block provide a 1A 24V dc
auxiliary power supply, for supplying interface equipment or other low current devices. Terminal 11 is
24V dc and terminal 12 is 0V dc.
24V
27K
10K Input