345
Troubleshooting
Section 11-3
Serial commu-
nications mode
is set to Mod-
bus-RTU slave
mode.
The RD
@
and
COM
@
indica-
tors are flash-
ing, but the
response has
not been
returned from
the host.
For the Unit, the
SD
@
indicator
does not flash
at all (Commu-
nications have
been electri-
cally estab-
lished.)
There is no
transmission
error.
---
Cables are incor-
rectly connected.
The RS-422A/485
port setting (2-wire
or 4-wire) is incor-
rect.
Adapters such as
the NT-AL001-E are
incorrectly wired or
set.
Check the wiring.
Reset the port to the cor-
rect wiring setting.
Wire all nodes using the 4-
wire method.
---
This is a transmis-
sion circuit hard-
ware error.
Conduct a loopback test in
serial communications
mode to check the trans-
mission lines. If an error
occurs during the test,
replace the Board or Unit.
The destination
Modbus slave
address in the com-
mand frame is set to
0, i.e., it is set for a
broadcast.
Correct the destination
Modbus slave address in
the command frame.
There is a
transmission
error.
In CIO Area words n
+ 8/n + 18, bit 15
(transmission error
status) is turned
ON, and bit 07(CRC
error), bit 04 (over-
run error), bit 03
(framing error), or
bit 02 (parity error)
is turned ON.
The communica-
tions conditions and
baud rate do not
match the settings
at the host.
Review the System Setup,
the host’s settings and pro-
gram (such as commands
and frame format) based
on the response contents,
and the transmission error
codes in CIO Area words n
+ 8/n + 18.
There is noise inter-
ference.
Use shielded twisted-pair
cables.
Lay power lines sepa-
rately using ducts.
Review the installation
environment to reduce
noise interference.
There is an error in
the CRC code
appended to the
host command
frame.
Append the correct CRC
code.
Serial commu-
nications
mode
Indicator
status
Status
information,
etc.
CIO Area
Cause
Remedy
Summary of Contents for SYSMAC CJ1W-SCU21-V1
Page 3: ...iv...
Page 5: ...vi...
Page 9: ...x...
Page 15: ...xvi...
Page 89: ...60 Basic Operating Procedure Section 1 9...
Page 151: ...122 RS 232C and RS 422A 485 Wiring Section 3 4...
Page 173: ...144 Host Link Function for Replacing Existing PLCs Section 4 6...
Page 223: ...194 Enhanced Protocol Macro Functions Section 5 6...
Page 277: ...248 Communications Frames Section 6 8...
Page 291: ...262 Basic Operating Procedure in No protocol Mode Section 7 4...
Page 301: ...272 Auxiliary Area and CIO Area Allocations Section 8 3...
Page 391: ...362 Introduction Appendix A...
Page 421: ...392 CompoWay F Master Protocol Appendix B...
Page 513: ...484 E5 K Digital Controller Read Protocol Appendix F...
Page 571: ...542 E5ZE Temperature Controller Write Protocol Appendix I...
Page 587: ...558 E5 J Temperature Controller Protocol Appendix J...
Page 627: ...598 ES100 Digital Controller Protocol Appendix K...
Page 661: ...632 V500 V520 Bar Code Reader Protocol Appendix M...
Page 697: ...668 3Z4L Laser Micrometer Protocol Appendix N...
Page 717: ...688 Visual Inspection System Protocol Appendix O...
Page 755: ...726 V600 V620 ID Controller Protocol Appendix P...
Page 763: ...734 Hayes Modem AT Command Protocol Appendix Q...
Page 767: ...738 Changing Communications Port Settings Using STUP 237 Appendix R...
Page 781: ...752 Revision History...