Examples Of Recommended Rs-232C Wiring; Connections For Echoback Test; Example For Cj2H Cpu Unit; A-4-3 Applicable Connectors And Recommended Cables - Omron CJ2 CPU UNIT User Manual

Appendices

Connections for Echoback Test

Use the following connections.
RS-232C port
Pin No. Signal name
2
3
4
5
1
8
7
A-4-3 Applicable Connectors and Recommended Cables

Examples of Recommended RS-232C Wiring

We recommend the following wiring methods for RS-232C, especially in environment prone to noise.
• Use shielded twisted-pair cable for communications cables.
• Use a twisted-pair cable for each signal line and SG (signal ground) to connect the CPU Unit to a
communications partner. Also, bundle all the SG lines at the Unit and at the other device and connect
them together.
• Connect the shield line of the communications cable to the hood (FG) of the RS-232C connector at
the Unit. Also, ground the protective earth (GR) terminal of the Power Supply Units on the CPU Rack
and the CJ-series Expansion Racks to a resistance of 100 Ω or less. The following example shows
connecting SD-SG, RD-SG, RS-SG, and CS-SG for Serial Communications Mode using a twisted-
pair cable using the peripheral bus.
CPU Unit
Pin
Signal
No. name
2 SD
3 RD
4
RS
5 CS
9 SG
Hood FG
1
FG
Note The hood (FG) is internally connected to the protective earth (GR) terminal on the Power Supply Unit
through the CPU Rack. FG can thus be connected by connecting the protective earth (GR) terminal on the
Power Supply Unit. The hood (FG) is also electrically connected to pin 1 (FG), but the connection resistance
between the shield and the FG is smaller for the hood. To reduce contact resistance between the hood (FG)
and the FG, connect the shield both to the hood (FG) and to pin 1 (FG).

Example for CJ2H CPU Unit

Power Supply Unit
GR
Ground to 100 Ω
or less
A-132
RS-422A/485 port
Pin No.
SD 3
RD 4
RS 1
CS 2
FG 5
ER
DR
External device
Signal
name
RD
SD
CS
RS
SG
FG
Shield
CPU Unit
Hood and GR connected
internally.
The hood will be grounded
if the GR terminal is grounded.
Signal name
SDA-
SDB+
RDA-
RDB+
FG
SG signal line
XM2S-0911-E
Example for CJ2M CPU Unit
Power Supply Unit
PA205R
POWER
L1
AC100-240V
INPUT
L2/N
GR
RUN
OUTPUT
AC240V
DC24V
Ground to 100 Ω
or less
CJ2 CPU Unit Hardware User's Manual
SG signal lines
bundled together
Aluminum foil
Pulse I/O Module
COMM