11 - 16
TROUBLESHOOTING11.
Table 11.1 Error Code List for the AnUCPU, A2US(H)CPU, A2ASCPU and A2USH board (Continue)
Error Massage
Error 
Code
(D9008)
Detailed 
Error 
Code 
(D9091)
CPU 
States
Error and Cause Corrective Action
"CASSETTE 
ERROR"
16 — STOP Memory cassette is not loaded. Turn off the PC power and load the 
memory cassette.
"RAM ERROR"
(Checked at 
power on.)
20 201 STOP The sequence program storage RAM in 
the CPU module caused an error.
Since this is CPU hardware error, consult 
Mitsubishi representative.
202 The work area RAM in the CPU module 
caused an error.
203 The device memory in the CPU module 
caused an error.
204 The address RAM in the CPU module 
caused an error.
"OPE CIRCUIT 
ERROR"
(Checked at 
power on.)
21 211 STOP The operation circuit for index 
qualification in the CPU does not work 
correctly.
Since this is CPU hardware error, consult 
Mitsubishi representative.
212 Hardware (logic) in the CPU does not 
operate correctly.
213 The operation circuit for sequential 
processing in the CPU does not 
operate correctly.
"OPE. CIRCUIT 
ERR."
(Checked at 
execution of the 
END 
instruction)
214 In the END processing check, the 
operation circuit for index qualification 
in the CPU does not work correctly.
215 In the END processing check, the 
hardware in the CPU does not operate 
correctly.
"WDT ERROR"
(Checked at 
execution of 
END 
processing.)
22 — STOP Scan time is longer than the WDT time.
(1) Scan time of the user's program has 
been extended due to certain 
conditions.
(2) Scan time has been extended due 
to momentary power failure 
occurred during scanning.
(1) Calculate and check the scan time of 
user program and reduce the scan 
time using the   instruction or the 
like.
(2) Monitor contents of special register 
D9005 using a peripheral device. If 
the contents are other than 0, power 
supply voltage may not be stable.  
Check power supply and reduce 
variation in voltage.
"END NOT 
EXECUTE"
(Checked at 
execution of the 
END 
instruction.)
24 241 STOP Whole program of specified program 
capacity was executed without 
executing the   instructions.
(1) When the   instruction was to 
be executed, the instruction was 
read as other instruction code due 
to noise.
(2) The   instruction changed to 
other instruction code due to 
unknown cause.
(1) Reset and run the CPU again.  If the 
same error recurs,
Since this is CPU hardware error, 
consult Mitsubishi representative.
"MAIN CPU 
DOWN"
26 — STOP The main CPU is malfunctioning or 
faulty.
Since this is CPU hardware error, consult 
Mitsubishi representative
"UNIT VERIFY 
ERR"
(Checked 
continuously.)
31 — Stop or 
Continue 
(set by 
parameter)
Current I/O module information is 
different from that recognized when the 
power was turned on.
(1) The I/O module (including special 
function modules) connection 
became loose or the module was 
disconnected during operation, or 
wrong module was connected.
Read detailed error code using a 
peripheral device and check or replace 
the module which corresponds to the 
data (I/O head number).
Or, monitor special registers D9116 to 
D9123 using a peripheral device and 
check or replace the modules if 
corresponding data bit is "1".
CJ
END
END
END