User Manual
Appendix B
GFK-1742F
Jan 2020
DSM314 Communications Request Instructions
393
Table 82: DSM COMM REQ Status Word Codes
Code Name
Code #
Description
Possible Corrective
Action
IOB_SUCCESS
1
All communications proceeded
normally.
None required.
IOB_PARITY_ERR
-1
A parity error occurred while
communicating with an
expansion rack.
Retry. Check hardware
–
expansion cables, DSM
module, etc.
IOB_NOT_COMPL
-2
After the communication was
over, the module did not
indicate that it was complete.
Retry. Verify the COMM
REQ parameters.
IOB_MOD_ABORT
-3
The module aborted the
communication.
Retry. Verify the COMM
REQ parameters.
IOB_MOD_SYNTAX
-4
The module indicated that the
data sent was not in the correct
sequence.
Verify the COMM REQ
parameters.
IOB_NOT_RDY
-5
The RDY bit in the module’s
status was not active.
Retry. Check DSM module.
IOB_TIMEOUT
-6
The maximum response time
elapsed without receiving a
response from the module.
Check DSM module. Verify
the COMM REQ
parameters.
IOB_BAD_PARAM
-7
One of the parameters passed
was invalid.
Verify the COMM REQ
parameters.
IOB_BAD_CSUM
-8
The checksum received from the
DMA protocol module did not
match the data received.
Retry. Check installation
for proper grounding,
shielding, noise
suppression, etc.
IOB_OUT_LEN_CHGD
-9
The output length for the
module was changed, so normal
processing of the reply record
should not be performed.
Verify the COMM REQ
parameters.
Corrective Action
The type of corrective action to take depends upon the application. If an error occurs during
the startup or debugging stage of ladder development, the advice to “Verify the
COMM REQ
parameters”
is appropriate. The same is true if an error occurs right after a program is
modified. But, if an error occurs in a proven application that has been running successfully,
the problem is more likely to be hardware related. The host controller fault tables should be
checked for possible additional information when troubleshooting Status Word errors.