Omron F3SG series User Manual page 154

Wiring/Installation
Properly connect an emitter to another emitter, and a receiver to another receiver, as shown below.
Secondary
sensor 1
(Emitter)
Primary
sensor
(Emitter)
If caps and Cascading Cables are not connected properly, the F3SG-RA enters lockout (when power is turned ON).
F3SG-R
130
User's Manual
Do not series-connect an emitter and receiver.
They will enter lockout state.
Secondary Secondary
sensor 1 sensor 1
(Receiver) (Emitter)
Primary Primary
sensor sensor
(Receiver) (Receiver)
Do not face different models of emitters and
receivers toward each other. They will enter
lockout state or will be unable to detect objects
Secondary
Primary
sensor 1
sensor
(Receiver)
(Emitter)
Primary
Secondary
sensor
sensor 1
(Emitter)
(Emitter)
Secondary
sensor 1
(Receiver)
Primary
sensor
(Receiver)