Mitsubishi Electric A960GOT User Manual page 96

8 ERROR CODES AND ERROR MESSAGES
Error Error
Check Timing
Code Messages
22 WDT ERR. When an End
instruction is
executed
31 UNIT When an End
VERIFY instruction is
ERR. executed
40 CONTROL_ During execution of
BUS ERR. FROM/TO
instruction set
At CPU power ON/
At reset
41 SP. UNIT During execution of
DOWN FROM/TO
instruction set
At CPU power ON/
At reset
43 I/O INT During interrupt
ERR.
44 SP. UNIT At CPU power ON/
LAY ERR. At reset
46 SP. UNIT During execution of
ERR. FROM/TO
instruction set
8 - 9
(2) Error messages appearing due to faulty ACPU bus connection and
measure against errors
Error detail
(1) The scanning time exceeds
the calculation congestion
monitoring time.
(2) The scanning time may be
extended by waiting for a
response from an SP module
that is down, and errors may
occur simultaneously.
The information stored in the
cards of the module installed in
the base module and the
communication module of the
GOT is different from that read at
the initial time.
(If an error occurs on a module
(vacant) other than that installed
in the base module, the mis-
operation may be caused by
noise.)
When the FROM/TO instruction
is executed, an imprecise
response is returned from the
special function module
(including the GOT).
At the time of initial
communication, an imprecise
response is returned from the
special function module
(including the GOT).
The special function module was
accessed during the execution of
a FROM/TO instruction set, but
there was no response.
At the time of initial
communication, a response is not
returned from the special function
module (including the GOT).
An imprecise interrupt occurs to
the PLC CPU.
Too many modules are installed
(see the PLC CPU specification).
The FROM/TO instruction is
executed to any module other
than the special function module.
Cause and check point
Remedy
(1) Use the error history to check whether
simultaneous occurrence errors are
present.
(2) Refer to the SP module down check
points.
Check the faulty module at special resisters
D9116 to D9123.
(1) Check that the module and the cables are
connected correctly.
(2) Check that the PLC and the GOT are
earthed correctly.
Check the faulty module from the error step.
(1) Check that the module and the cables are
connected correctly.
(2) Replace the faulty module with a new
one.
(3) Check that the PLC and the GOT are
earthed correctly.
(1) Check that the module and the cables are
connected correctly.
(2) Because a faulty module cannot be
located, remove the modules one by one
until no CONTROL_BUS ERR. message
appears to indicate the module where the
error occurs.
(Because the modules are removed, SP.
UNIT ERR. message may appear. Stop
transmitting the FROM/TO instruction to
the applicable module.)
Check the faulty module from the error step.
(1) Check that the module and the cables are
connected correctly.
(2) Replace the faulty module with a new
one.
(3) Check that the PLC and the GOT are
earthed correctly.
(1) Check that the module and the cables are
connected correctly.
(2) Replace the faulty module with a new
one.
(3) Check that the PLC and the GOT are
earthed correctly.
(1) Check the number of installed modules.
(2) Check the number of extension stages
and the I/O slot numbers.
(1) Review the sequence program.
(2) Check the number of extension stages
and the I/O slot numbers.
MELSEC-GOT
Corresponding
CPU
ACPU
8 - 9