Omron 3G3MV-PDRT2, Руководство пользователя

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Chapter 6
6-7
Message Communications
6-3 Overview of Messages and Responses
When message communications are used, the Inverter's DeviceNet Communications Unit/Card
returns responses as explained below.
Basically, DeviceNet communications are executed in 1-byte (8-bit) units. In the case of single-word
data (16 bits), the rightmost bits (least significant) and the leftmost bits (most significant) are
reversed in order due to the following reasons:
• Data on communications line is transmitted in the order of rightmost bits and leftmost bits.
• Data that is internally processed by PLC for issuing commands is transmitted in the order of left-
most bits and rightmost bits.
Therefore, reverse the order for attributes where “Word” is written in the “Size” column in the tables
on subsequent pages and create attached data or read response data.
Note There is no need to take this into consideration for remote I/O because the rightmost bits and
leftmost bits are automatically reversed.
■ Command Format
■
Response Format
●
Normal Response
● Error Response
● Failure or Timeout during Transmission
28 01
Service
Code
Class ID Instance ID Service Data
28 01
32 bytes max.
Command code
(FINS command for
PLC)
Destination
node
address
Service data (attribute
No. or attribute No. and
write data)
28 01 28 01 00 00
Service
Code
32 bytes max.
Service data
(read data)
Command code
(FINS command for PLC)
Completion code
Number of bytes
transmitted
Destination
node
address
28 01
Error Code
28 01 00 00
Service
Code
94
Completion
code
2 bytes
Destination
node address
Number of bytes
transmitted
Command code
(FINS command for PLC)
28 01 28 01
Command code
(FINS command for PLC)
Completion code
(FINS error code)