Rockwell Automation Allen-Bradley POINT Guard - Page 71

Rockwell Automation Publication 1734-UM013J-EN-P - July 2014 71
Install the Module Chapter 4
In the following two examples, the negative terminal of the sensor power supply
and that of the 1734 terminal base COMMON must be at the same potential.
Use of an external power supply limits diagnostics and increases susceptibility to
noise.
Follow the Guidelines for Wiring Safety Analog Inputs
on page 65.
Figure 41 - 4-wire Voltage or Tachometer Sensor (SIL 2) with External Power Supply
Figure 42 - 4-wire Current Sensor (SIL 2) with External Power Supply
IMPORTANT
You are responsible for making sure that the sensor is receiving appropriate
power. Safety sensors that are not properly powered may not deliver accurate
signals to the analog input module.
V0
DC
V1 V2 V3
I0 I1 I2 I3
COM COM COM COM
S0
FE
S1 S2 S3
+
-
Signal Return and Common are at the same potential.
1734-TB Terminal Bases
Signal (V)
+24V
Cable Shield
Signal Return
4-wire
Sensor
See Figure 43
and Figure 44 on page 72 for tachometer wiring detail.
V0
DC
V1 V2 V3
I0 I1 I2 I3
COM COM COM COM
S0
FE
S1 S2 S3
+
-
Signal Return and Common are at the same potential.
1734-TB Terminal Bases
Signal (V)
+24V
Cable Shield
Signal Return
4-wire
Sensor