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12. TROUBLESHOOTING
MELSEC-A
12. TROUBLESHOOTING
This chapter describes errors which can occur with the AlSJ71C24 procedures.
12.1
NAK
Error Codes with Dedicated Protocols
Table 12.1 gives the error codes and their descriptions when the NAK code
is transmitted between the computer and the PC CPU as 2-digit ASCII
(hexadecimal) between O O H and FFH.
If several errors occur simultaneously, the code with the lowest number takes
precedence and is transmitted.
If any of the following errors occur, the transmission sequences are initialized
and LED NEU (LED No. 8) is turned ON.
Table 12.1 Error Code List
-
Error
Error Description
Invalid access has been made during RUN.
(1) Data has been written to a At SCPU with
the SW04 OFF (write disable during RUN).
(2) Sequence program and parameters have
been written.
indicator
LED No.
Corrective Actions
Disable
during
RUN
(1) Start communicationss after
turning ON SW04.
(2) Write parameters after set-
ting the AISCPU to STOP.
CiN
(LED No.1 I )
O O H
Parity
error
Parity error
With the SW09 ON (parity enabled), the
parity check result does not match the
state of SWlO (oddleven ~aritv).
PIS
(LED No.12)
PIS
(LED No.12)
PRO
(LED No.13)
SIO
(LED No.14)
Check control protocol.
change the SW setting or
data.
Sum check error
With the SW12 ON (sum check enabled).
the sum check result of received data
does not match the sum check code of
transmitted data, i.e.. send data is dif-
ferent from received data.
Communications protocol not valid.
Sum
check
error
Check data transmitted from
computer and sum check
resuh. Correct invalid data.
Protocol
error
Chock and correct the modc
setting switch position and
control protocol and restart
Communications have been made with a
protocol different from the one set by the
mode settina switch.
data communications.
-
Framing error
Data does not match the setting of SW11
(stop bit).
Framing
error
Change the setting of SWt 1
or the control protocol.
Overrun
error
Overrun error
New data has been transmitted before
AlSJ71C24 receives ail the preceding
data.
SIO
[LED No.14)
PRO
:LED No.13)
Decrease the data transmis-
sion speed and restart data
communications.
Character area A. B, or C error, or designated
command does not extst.
(1) Check and correct the char-
acter area A,B, or C and res-
tart data communications.
(1) The dosignation of the character area A,
6, or C for the control protocol set with
the
mode setting switch 0 s not correct.
(2) See the functions list in Sec-
tion 3.3.1 and the AISCPU
User's Manual to correct the
designated commands, and
restart data communications.
:3)
See Section 8.7.1 to correct
the number of
seiti
:haracter
ired error
12) A command used with the ~rotocol does not exist
. .
(For example, a subsequence program was
designated to be used wiih AISCPU.)
T k 5 4 ~ ~ c k e s m t e d s t n h e s e t P C C R I .
(3) The device number is not set with the re-
quired number of characters.
(ACPU common command:
5
characters,
AnACPU dedicated command: 7 characters)
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