Omron NS - MANUAL 2 Operation Manual page 25

Grounding Precaution
Either ground the Camera, PT, and PLC at only one point, or connect the grounds
for each with a special line. Some computers internally connect the SG terminal to
the RS-232C and USB connector hoods. If such a computer is connected to the PT
or PLC and there is a ground potential difference between the Camera and the
PT/PLC, an overcurrent may flow through the electronic components inside the
NS-CA002 as shown in the following figure, possibly damaging the NS-CA002.
Camera
Video Cable
SG SG
Case
Recommended Connections
Ground to only one point as shown in the following figure or use equivalent wiring so
that there is no difference in ground potential.
Camera
Video Cable
SG SG
Case
2-3 Installing the RGB and Video Input Unit
NS-CA002 PT
Electronic
component
Functional
ground
Difference
in potential
NS-CA002
PT
Electronic
component
Functional
ground
PLC
RS-232C cable
SG SG
RS-232C
connector hood
*The example in the above figure shows a computer connected to
an RS-232C connector on the PLC.
PLC
RS-232C cable
SG SG
RS-232C
connector hood
Computer
RS-232C cable
SG SG
RS-232C
connector hood
LG
GR
Computer
RS-232C cable
SG SG
RS-232C
connector hood
LG
GR
2-9