YOKOGAWA VZ20X, User Manual

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IM 77V01B01-01EN 5th Edition: 2023.03.07-00
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Response error code
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When a response is returned to a request
・
When there is a nonconformity in the PDU in the request, VZ20X performs no
processing, and returns the following request.
MBAP Header PDU
Number of
bytes
2 2 2 1 1 1
Command
elements
Transfer
ID
Protocol
ID
Number
of bytes
Unit ID Function
code*
Error
Code
(Hex) Arbitrary 0000 03 01
*The number of the function code (Hex) + 80 (Hex) is input to the function code.
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Response error code
Error Code Meaning Cause
01 Function code error The function code does not exist.
02 Register No. error A No. out of range was specified.
03 Number of registers error A number of registers out of range was specified.
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When a response is not returned to a request
In the following cases, VZ20X performs no processing and does not return a response.
・
When a connection has not been established on the TCP/IP socket interface
・
When there is a nonconformity in the MBAP Header in the request
Note: As a countermeasure for the above, perform timeout processing by the communication function on the host device or
by the communication program.