Rockwell Automation 1734-IE4S POINT Guard I/O Safety Modules User Manual - Manual (Page 69)

Rockwell Automation Publication 1734-UM013J-EN-P - July 2014 69
Install the Module Chapter 4
Figure 37 - 3-wire Voltage or Tachometer Sensor (SIL 3)
Figure 38 - 3-wire Current Sensor (SIL 3)
Follow the Guidelines for Wiring Safety Analog Inputs on page 65 .
V0 V1 V2 V3
I0 I1 I2 I3
COM COM COM COM
S0
FE
S1 S2 S3
FE
This wiring configuration may also be used for SIL 2 redundant Tachometer mode.
For analog voltage-output sensors, the signal levels for operation for the application must be outside the signal level when the signal is not
present, for example, when the wire is broken.
Field sensors are monitoring the same signal in a redundant configuration.
You must configure a safety discrepancy deadband between the two signals to achieve SIL 3.
SIL 2
3-wire
Sensor
1734-TB Terminal Bases
Signal (V)
+24V
Cable Shield
Cable Shield
+24V
SIL 2
3-wire
Sensor
Signal (V)
Signal Return
Signal Return
See Figure 43 and Figure 44 on page 72 for tachometer wiring detail.
V0 V1 V2 V3
I0 I1 I2 I3
COM COM COM COM
S0
FE
S1 S2 S3
FE
For 0…20 mA analog current-output sensors, the signal levels for operation for the application must be outside the signal level when the signal
is not present, for example, when the wire is broken.
Field sensors are monitoring the same signal in a redundant configuration.
You must configure a safety discrepancy deadband between the two signals to achieve SIL 3.
SIL 2
3-wire
Sensor
1734-TB Terminal Bases
Signal (I)
+24V
Cable Shield
Cable Shield
+24V
SIL 2
3-wire
Sensor
Signal (I)
Signal Return
Signal Return