Mitsubishi Electric A173UHCPU User Manual page 132

5. INSPECTION AND MAINTENANCE
Contents (BIN)
Error
Register D9008
"CHK FORMAT
ERR."
"CAN'T
EXECUTE (I)"
"RAM ERROR"
"OPE. CIRCUIT
ERR."
"WDT ERROR"
Table 5.9 Table of Error Codes (cont.)
CPU
of Special
Status
14 STOP
15 STOP
20 STOP
21 STOP
22 STOP
Error Description and Cause
(1) A CHK instruction ladder block
contains an instruction (including
NOP) other than LDX, LDIX,
ANDX, ANIX.
(2) Multiple CHK instruction exist.
(3) More than 150 contacts exist in a
CHK instruction ladder block.
(4) The X device number in a CHK
instruction ladder block exceeds
X7FE.
(5) No ladder block exists before the
CHK instruction ladder block.
CJ
(6) The [CHK] [D1] [D2] instruction
D1 device number does not match
the device number of the contacts
before the CJ instruction.
(7) No pointer P254 exists at the start
of the CHK instruction ladder
block.
P254
CHK D1 D2
(1) An interrupt module is used, but
the program contains no
equivalent interrupt pointer I
number, or duplicate interrupt
pointers.
(2) No IRET instruction exists in
interrupt program.
(3) An IRET instruction exists outside
the interrupt program.
(1) A check determined normal
reading and writing to the CPU
data memory area is not possible.
(1) The CPU operation circuits which
handle sequence processing are
inoperative.
The scan time exceeded the
watchdog timer set time.
(1) Scan time too long because of
user program conditions.
(2) Scan time too long because of
instantaneous power interruption
during scan.
5 − 21
Corrective Action
(1) Check the CHK instruction
ladder block for items (1) to (7)
in the column to the left. Correct
problems with the peripheral
device and start operation again.
(2) This error message is valid for
direct I/O control only.
(1) Check if an interrupt program
exists for the interrupt module,
then create an interrupt program
or eliminate duplicate I numbers,
as appropriate.
(2) Check if IRET instruction exists
in the interrupt program, and
insert, if required.
(3) Check if an IRET instruction
exists outside the interrupt
program, and remove, if
necessary.
A problem with the CPU hardware.
Contact your nearest Mitsubishi
representative with details.
(1) Calculate and check the scan
time in the user program, reduce
the scan time with the CJ
instruction.
(2) Monitor the contents of special
register D9005 from a peripheral
device. A non-zero value
indicates an unstable power
supply voltage. If the value is not
0, check the power supply and
reduce the voltage fluctuations.