End Code - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

■End code

The error code is stored in the end command added to the response. ( Page 331 End Codes Returned to an External
Device During Data Communications)
The end code is also stored in the BUFSND instruction and BUFRCV instruction completion status area (inside control data).
The following cases may apply if an error code for communications using the SLMP or random access buffer is stored even
when executing communications using the fixed buffer.
Description
The data length specified in the application data section of the message sent
from the external device to the RJ71EN71 or the RnENCPU (network part)
differs from the actual data size in the text section.
The subheader of the message sent from the external device to the
RJ71EN71 or the RnENCPU (network part) is incorrect.
The communication data may be split and exchanged due to buffer limitations to the own station or external station. The data
that is split and received is restored (reassembled) by the RJ71EN71 or the RnENCPU (network part) and exchanged. (The
received data is restored (reassembled) based on the data length in the communication data.) The RJ71EN71 and the
RnENCPU (network part) processing that take place when the data in the communication data is incorrect are shown below.
Communication Description
Method
Fixed Buffer When data length specified immediately after subheader < text data volume
(Procedure Exist), • The data immediately after the text corresponding to the data length specified immediately after the subheader is handled as the
Random Access second message.
Buffer • The start of each statement becomes the subheader, so the RJ71EN71 and the RnENCPU (network part) execute a processing
corresponding to the subheader code.
• If the subheader is not a code supported by the RJ71EN71 and the RnENCPU (network part), an abnormal completion response is
sent to the external device.
Data sent from the external device
Subheader
In the above case, the code processed as the subheader with the uppermost bit set as 1 is returned as the response.
For example, if the command's subheader section is 65H, the response's subheader is E5H.
When data length specified immediately after subheader > text data volume
The RJ71EN71 and the RnENCPU (network part) wait to receive the insufficient remaining data.
If the remaining data is received within the response monitor timer value, the RJ71EN71 and the RnENCPU (network part) execute a
processing corresponding to the subheader code.
If the remaining data is not received within the response monitor timer value, the RJ71EN71 and the RnENCPU (network part) execute
the following processing.
• The ABORT(RST) instruction is sent to the external device, and the line is closed.
• The error code is stored in 'Connection status storage area' (Un\G100 to Un\G163).
Fixed Buffer (No During nonprocedural, there is no message data length, so the received data is stored as is into the receive buffer area. Providing a
Procedure) check procedure including the data length, data type code, and so on, in the message's application data is recommended so that the
application data's byte size and data type can be seen on the receiving side.
Remedy method
Specify the actual data size in the text section as the data length in the
application data section. (Refer to the following descriptions.)
Review the subheader specified in the application data section.
Data processed by the RJ71EN71 or the RnENCPU (network part)
(1st data) (2nd data)
Subheader
This section is processed as a subheader.
1.5 Communications Using the Fixed Buffer
1
1 FUNCTIONS
83