Mitsubishi Electric AJ71C24-S6 User Manual page 278

11. TROUBLESHOOTING
MELSEC-A
11.2 Bidirectional Mode Error Codes
Table 11.2 gives the error codes, error descriptions, and corrective actions
for errors which may occur during bidirectional mode communications.
The following error codes (l-word integers) are transmitted in order of the
lower byte and the higher byte immediately following the NAK code when an
error has occurred. (e.g., when the error code is 01
H,
01 H
is transmitted first,
and then
0 0 ~
is transmitted.)
Table
11.2
Error Code List
Error Code
'lexadecimal
Error Descriptions
Send data length error
Response message time-out error
Simultaneous transmission error
Error code is not received when the
NAK code is received
Errors designated by the
usel
SIO error at data receive
Framing error
Overrun error
Check sum error
Parity error (only at data receive)
Received data length error
Received data time-out error
Corrective Actions
Either (a) make the setting size of the send data length
storage area in the buffer memory for bidirectional
transmission smaller than the size of the send data storage
area, or (b) set the send data length to '1' or greater.
(Data which does not have a data part cannot be
transmitted using the bidirectional mode.)
Set the computer so that it transmits the response message
(in response to the data received from the AJ7tC24) to the
AJ71 C24 within the set value of the time-out time setting
area (address 113H) in the AJ71C24 buffer memory.
Either (a) interlock the computer with the AJ7tC24 so that
they cannot begin transmitting data simultaneously to each
other, or (b) set the data validlinvalid setting
area
(address
t14H) in the AJ7tC24 buffer memory to 'valid'.
When the computer transmits the NAK code to the
AJ71C24 in response to the data received from the
AJ71C24, an error code should be added immediately after
the NAK code.
These error codes are added to immediately after the NAK
code.
Take corrective actions according to the procedure fixed
by user.
Transmit data from the computer according to the follow-
ing settings with the AJ71C24 (see Section 4.3.2 for
SWl2 to SW18).
Data bit length with SWt2
Transmission speed with SW13 to SW15
Stop bit length with SW18
Use insulation transformers (noise-cutting transformers)
to eliminate noise.
To transmit the check sum to the AJ71 C24, obtain the
check sum as described in Section 10.5.2.
Set the check sum enableldisable setting area (address
t15H) in the AJ71 C24 buffer memory to 'disable', so that
the check sum is not transmitted.
Transmit data from the computer accord ng to settings
witn SWt6 and SW17 of the AJ7tC24.
Either (a) make the data part length and the set value of
the data part length of the receive message less than the
size of the received data storage area, or (b) transmit
correctly the data length (000tH or more) contained in the
message which is transmitted to the AJ71C24.
(Data which does not have the data part cannot be
transmitted usina the bidirectional mode.)
-
~ ~ ~ ~~~~
When data is transmitted from the computer, set the actual
length of the data part to the data length part.
(The AJ71C24 executes the time-out check (as set with
address 113H of the buffer memorv) if it fails to receive
data of
a
set length. This
error
occurs when it fails to
receive the next data within the set time.)