User`s manual

Error code list Troubleshooting
MELSEC System Q, Hardware 11 – 25
11.3 Error code list
The LED on the front side of the CPU indicates an error, recognised by the self diagnostics func-
tion of the CPU during transition to RUN mode or during PLC operation. At the same time an
error code is saved into special register SD0, which can be displayed together with the appro-
priate error message by the error diagnostics function of the programming software GX Devel-
oper or GX IEC Developer.
The special registers SD5 to SD15 contain general information and the special registers SD16
to SD26 the specific information about the error (refer to column "Error contents and cause" in
the error code lists of sections 11.3.1 to 11.3.7).
The sign "" in the last column of the error code list indicates, that the error code is valid for all
CPU types of MELSEC System Q. If a CPU type is mentioned there, this means, that the error
code is only valid for this special CPU type.
– Qn(H) = High performance model QCPU Q02-, Q02H-, Q06H-, Q12H- and Q25HCPU
– QnPH = Process CPU module Q02PH-, Q06PH-, Q12PH- and Q25PHCPU
– QnPRH = Redundant CPU module Q12PRH- and Q25PRHCPU
– QnU = Universal model QCPU
The relation between the error detection pattern, error detection location and error code is
shown in the following table.

Major error: errors that may cause the CPU module to stop the operation.

Minor or moderate error: Errors that may allow the CPU module to continue the operation, e.g., battery error or
errors that may cause the CPU module to stop the operation, e.g., WDT error. For determination of the error level
(i.e. whether the operation can be continued or stopped) refer to column "CPU status" in the error code lists of
sections 11.3.1 to 11.3.7).
Error detection pattern Error detection location Error code Reference
Detection by the self diag-
nostics function of CPU
module
CPU module
1000 to 1299

Sections 11.3.1 to 11.3.7
1300 to 10000

Detection at communica-
tion with CPU module CPU module 4000
H to 4FFF H
The CPU module returns the
error code to the request
source.
Serial communication mod-
ule
7000
H to 7FFF H Manual of corresponding mod-
ule
CC-Link module B000
H to BFFF H
ETHERNET module C000 H to CFFF H
CC-Link IE controller net-
work
E000 H to EFFF H
MELSECNET/H network
module
F000 H to FFFF H
Tab. 11-2: Error codes