Mitsubishi Electric QJ71MB91 User Manual page 311

11
TROUBLESHOOTING
(3) Troubleshooting for other symptoms
No. Symptom
Dedicated instruction is
not executed.
1
(The completion device
does not turn on.)
Dedicated instruction
2
failed.
Table11.3 Troubleshooting for other symptoms
Check point
Check if the dedicated instruction is
started.
Is the programmable controller CPU in the
RUN status?
Check if more than the maximum number
of simultaneously executable dedicated
instructions (one per channel) are started.
Check if the dedicated instruction is
completed in error.
Check if a dedicated instruction is already
being executed and the module is waiting
for a response from the target device.
Check the error code and/or exception
code stored in the control data of the
dedicated instruction.
Does the target device support the
function code?
In the case of the MBREQ instruction,
check if the contents of the request
message is correct.
Check if the Response monitoring timer/
Broadcast delay of the dedicated
instruction is appropriate.
Corrective action
Start the dedicated instruction.
Set the programmable controller CPU to
RUN.
Complete the dedicated instruction
currently executed, and then retry.
Refer to "Dedicated instruction failed."
• Wait until the response monitoring timer
for the dedicated instruction times out.
• Check the status of the target device.
• For the error, refer to "Dedicated
instruction failed."
Take corrective actions according to the
error and exception codes, and retry.
<MBRW instruction>
Modify the device type setting in the
control data so that a function code
supported by the target device will be
issued.
<MBREQ instruction>
Modify the send data so that a function
code supported by the target device will be
issued.
Correct the request message and retry.
• Check the processing time of the target
device.
• Check if, because of a small response
monitoring timer value, the timer has
timed out with an error before the target
device returns a response.
For the error, set a larger response
monitoring timer value.
• Check if the next request was sent
before completion of the processing of
the target device because of a small
broadcast delay value.
For the error, set a larger broadcast
delay value.
(Continued on next page)
11.1 Troubleshooting
9
Reference
10
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CHAPTER 10
11
This section
(3)-2
This section
(3)-2
CHAPTER 10
Section 11.4
Section 10.2
Section 10.3
CHAPTER 4
Section 10.3
Section 7.2.1
11
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