YOKOGAWA VZ20X, User Manual

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IM 77V01B01-01EN 5th Edition: 2023.03.07-00
7.2.6 Details of Commands/Responses
These are commands that are used by the PC/PLC for obtaining the information in
registers on the VZ20X or for acquiring data.
Function code Description
03 Read multiple registers
06 Write single register(*)
16 Write multiple registers
70 Data acquisition control
71 Acquire data
*: Function code 06 is enabled with firmware version R1.02.01 or later.
■
03 Read multiple registers
●
Function
The content of registers is read continuously for the number of specified points from the
specified register No.
・ The maximum number of registers that can be read in a single operation is 100.
・
For details on the response format when an error occurs, refer to the response
configuration.
●
Message (during normal operation)
Element MBAP Header PDU
Number of
bytes
2 2 2 1 1 2 2
Command
elements
Transfer ID Protocol
ID
Number of
bytes
Unit ID Function
code
(0x03)
Register
start No.
(Hex
number)
Read
Number of
registers
(Hex) Arbitrary 0000 0006 01 03 n
●
Response (during normal operation)
Element MBAP Header
Number of
bytes
2 2 2 1
Command
elements
Transfer
ID
Protoc
ol ID
Number
of bytes
Unit ID
(Hex) Arbitrary 0000 2n+3 01
Continuation of response
PDU
1 1 2 2
Function
code
(0x03)
Byte
count
(Note 1)
Register
content
... Register
content n
03 2n
Note 1: Byte count = 2 x number of read registers