Chapter 3
Installation
MAN_105G_1.16
Page 100
DPV1 Acyclic Read
MSAC1_READ: Command Number = 0020h
This command initiates a DPV1 Class 1 acyclic read request. Consult EN50170 (DPV1) for
more information.
Command and response layout:
Command
Response
Message ID
(ID)
(ID)
Message Information
4002h
0002h
Command Number
0020h
0020h
Data Size
0000h
(Size of data)
Extended Word 1
Slave Add
Slot No.
Slave Add
Slot No.
Extended Word 2
Index
Length
Index
Length
Extended Word 3
-
-
Extended Word 4
-
-
Extended Word 5
-
-
Error Decode
Extended Word 6
-
Err Code1
Err Code2
Extended Word 7
-
Return Code
Extended Word 8
-
Fault Information
Response data byte 1
Data 1
Response data byte 2
Data 2
:::
:::
Response data byte n
Data n
•
Slave Address
Station address of the slave responder
•
Slot Number &Slot Index
Used in the slave to address the desired data block.
•
Length
This parameter specifies the number of bytes of the data block that has to be read. If the
server data block length is less than requested, the length of the response will be the
actual length of the data block. If the server data block is greater or equal, then the
response will contain the same amount of data.
The slave may answer with an error response if the data access is not allowed.
•
Data [1 ...n]
Returned data
•
Return Code
See "Return Codes" in section “DP Error Codes ” below.