Troubleshooting
Section 7-2
89
Message Communication problems
Description
Possible cause
Possible remedy
IOWR instruction
not successfully
executed
Output mailbox is full. The Output mailbox is
not able to process new command messages
when the Input mailbox is not able to receive
reply messages.
Clear the messages in the Input mailbox to
enable the Input mailbox to receive new
messages and the Output mailbox to process
new messages. The messages can be
cleared by using IORD instructions or by
setting IR n.01 of the control words.
The RUN-bit (IR n.00) is not switched ON or
the communication is inhibited (IR n.01)
Set the RUN-bit and enable communication
again.
The IOWR instruction contains syntax errors
Check the IOWR instruction. Is the correct
Unit number and message length specified?
The transferred command message is not
correct.
Note:
This error can not be detected by the
result of the EQ-flag!
Check the command message that is created
in the PLC data area. Does it comply with the
command messages definition specified in
section 6-4?
The Master Unit is faulty
Replace the Master Unit.
IORD instruction not
successfully
executed
There is no reply message in the Input mailbox
Only read a message when IR n+2.13 (Reply
in input mailbox) is set.
The IORD instruction contains syntax errors
Check the IORD instruction. Are the correct
Unit number and message length specified?
The Master Unit is faulty
Replace the Master Unit.
Command was not
successfully
executed though
IR n+2.12 (Output
mailbox full) is not
set.
Issued more than one IOWR per PLC scan or
issued an IOWR after issuing a control
command via the control words in the previous
PLC scan. In both cases, IR n+2.12 has not
been updated and the mailbox could just have
been filled up and be unable to process more.
Do not issue more than one IOWR per PLC
scan or do not issue an IOWR after issuing an
control command via the control words in the
previous PLC scan.
For other reasons see situation ‘IOWR
instruction not successfully executed’
-
IORD command
was not executed
successfully though
IR n+2.13 (Reply in
input mailbox) was
set.
Issued more than one IORD per PLC scan or
issued an IORD after issuing an ‘Input mailbox
clear’ command via the control words in the
previous PLC scan. In both cases IR n+2.13
has not been updated and the Input mailbox
could just have been cleared.
Do not issue more than one IORD per PLC
scan or do not issue an IORD after issuing an
‘Input mailbox clear’ command via the control
words in the previous PLC scan.
For other reasons see situation ‘IORD
instruction not successfully executed’
-
ERR LED is
switched ON
A fatal error is detected. The cause is reported
in IR n+2.06 ~ IR n+2.08
Try to solve the cause and / or restart the
Unit. If this does not help, replace the Master
Unit
Summary of Contents for C200HW-PRM21
Page 1: ...C200HW PRM21 PROFIBUS DP Master Unit OPERATION MANUAL Cat No W349 E2 2...
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Page 5: ...C200HW PRM21 PROFIBUS DP Master Unit Operation Manual Produced May 2000...
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Page 66: ...Debug mode Section 4 4 50...
Page 98: ...Messages Section 6 4 82...
Page 108: ...Maintenance Section 7 3 92...
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