Mitsubishi MELSEC LJ71C24, User Manual

Page: 296 / 428

15 - 27 15 - 27
15 TROUBLESHOOTING
Protocol
Error code
(Hexa-
decimal)
Error
Description
Signal
name
Corrective action
MC
Non-
proce-
dural
Bi-
direc-
tional
Pre-
defined
7F21
H
Receive header
area error
•
There is an error in the command
(frame) part.
•
An ASCII code that cannot be
converted to binary code was received.
PRO.
•
Check and correct the external device
transmit message and restart data
communications.
7F22
H
Command error
•
A nonexistent command, subcommand,
or device was designated.
•
The remote password length is wrong.
PRO.
•
Check and correct the external device
transmit message and restart data
communications.
7F23
H
MC protocol
message error
•
There is no data (ETX, CR-LF, etc.)
following the character area, or
designation was incorrect. PRO.
•
Check and correct the external device
transmit message and restart data
communications.
7F24
H
Sum check error
•
The sum check code calculated does
not match the sum check code
received.
•
The horizontal parity code calculated
does not match the horizontal parity
code received.
•
The calculated error check code does
not match the received error check
code.
P/S
•
Check the sum check code of the
external device.
•
Check the horizontal parity code
calculated of the external device.
•
Check CRC-16 of the external device.
•
If the predefined protocol was edited,
check if the following values match the
packet format of the external device:
1) Processing method or code type of
the error check code
2) Data length
3) Data flow
4) Complement calculation
5) Calculating range
7F25
H
Data length error
•
The length of the received data
exceeds the receive area size.
CHn
ERR.
•
Correct the "data length" that is
transmitted from the external device.
•
Change the "word/byte units" setting to
“byte units”.
•
Increase the receive buffer memory
length designation value.
7F26
H
Command error
•
Another command was received before
an unlock processing while the remote
password is registered.
CHn
ERR.
•
Perform the communication after the
unlock processing is normally
completed.
7F30
H
System error
•
The OS of the C24 detected some
error.
⎯
( 1)
7F31
H
Simultaneous
transmission error
•
The C24 and an external device started
transmissions simultaneously.
⎯
•
Perform processing according to the
predefined arrangement with the
external device.
•
When necessary, change the
simultaneous transmission data
valid/invalid designation setting.
(address: 9B
H
/13B
H
)
7F32
H
System error
•
The OS of the C24 detected some
error.
⎯
( 1)
7F40
H
•
No reception watchdog timer (timer 0)
time-out occurred.
PRO.
•
Check if data was dropped from the
receive data.
•
Check if DTR control, etc. interrupted
reception.
7F41
H
•
Response watchdog timer (timer 1)
time-out occurred.
⎯
•
Check the status of the external device,
and restart data communications, as
required.
7F42
H
Time-out error
•
Transmit watchdog timer (timer 2) time-
out occurred.
⎯
•
Check if DTR control, etc. interrupted
transmission.
7F50
H
to
7F54
H
7F60
H
to
7F66
H
System error
•
The OS of the C24 detected some
error.
⎯
( 1)