Mitsubishi MELSEC LJ71C24, User Manual

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15 TROUBLESHOOTING
15.3.10 Communication error "PRO."
Symptom Cause Corrective action
MC
B
idi
rec
tional
Non-
proc
edur
al
P
redef
ined
• Communications were
performed with a control
procedure different from the
C24 communication protocol
setting.
• Some of the data are
different from the control
procedure.
• Designated command does
not exist.
• The device No. designation
is not the character count
corresponding to the
command.
• Check the C24 communication protocol setting and
the message from the external device and match the
settings, or correct the message and restart data
communications.
• Use the communication monitoring function to check
the message from the external device.
• The characters in the
message include a data
other than the "A to Z", "0 to
9", "(SP)", and control data.
• Check and correct the external device message and
restart data communications.
• Use the communication monitoring function to check
the message from the external device.
Note
• Only the data "0 to 9" and "A to F" can be handled
as character area data during communications
using an MC protocol (ASCII mode). Therefore,
when transmitting a character string as data,
convert the ASCII code of each character string to
2-byte binary code.
Examples)
• Transmitting the character "G"
The ASCII code for the character "G" is 47
H
and
is transmitted as the two bytes 34
H
, 37
H
.
• Transmitting the character "A"
The ASCII code for "A" is 41
H
and is transmitted
as the two bytes 34
H
, 31
H
.
If the ASCII code 41
H
for the character
"A" is transmitted unchanged, the C24
ASCII-BIN conversion will convert it to
A
H
(10) and pass it to the CPU module.
• A device No. outside the
designated range was
designated.
• When specifying a device, check "Device setting" of
the parameters written to the CPU module and
correct it to a device No. within the designated range
and restart data communications.
• Communication error
signal "PRO." turned
on.
• A remote RUN/STOP
request was issued while
remote STOP was applied
from another module.
• Check if remote STOP is applied from another
module and restart data communications.