1:N Nt Link Mode - Omron CQM1H-SCB41 Operation Manual

Troubleshooting
9-2-3

1:N NT Link Mode

Serial commu- Indicator
nications mode display
Serial communi- ---
cations mode is
not set to NT
Link.
Serial communi- The COMM@
cations mode is indicators do not
set to NT Link. flash at all.
(Communica-
tions have not
been electri-
cally estab-
lished.)
The SD and
COMM@ indica-
tors are flashing,
but the Serial
Communica-
tions Board can-
not
communicate
with the Pro-
grammable Ter-
minal (PT).
132
Status I/O memory
information,
etc.
--- Bits 12 to 15
(Serial Commu-
nications Mode)
of DM 6555/
DM 6550 are set
to a value other
than 5 Hex.
--- ---
--- ---
Cause
Serial communica- Set bits 12 to 15 (Serial
tions mode is not set Communications Mode) of
correctly. DM 6555/ DM 6550 to
5 Hex.
There is a hardware Conduct a loopback test in
error. serial communications
mode to check the trans-
mission lines. If an error
occurs during the test,
replace the Serial Commu-
nications Board.
There is a setting Correct the PT serial port
error for the PT serial settings.
port.
The I:N NT Link unit Review the NT Link unit
number of the PT is number of the PT.
incorrect.
The same 1:N NT
Link unit number has
been set for more
than one PT
The maximum allow- Review the PC Setup set-
able NT Link unit tings.
number is incor-
rectly set for the sys-
tem.
Cables are incor- Review the wiring or switch
rectly connected. settings.
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.
A communications Review the wiring and
error frequently installation environment.
occurs due to noise,
etc.
There is a PT hard- Replace the PT.
ware error.
Section 9-2
Remedy