User manual

Modbus RTU 23MN744
Parameter Support Continued
Parameter Upload
(Sub-Code 3)
This PDU is used to provide parameter upload functionality from the drive to a host. Only parameters stored in
the control's EE are uploaded. Only one multi-block Modbus operation may be performed at a time. The
O-scope, parameter upload and parameter download all require multi-block support. They are sent in parameter
index order, each parameter data set taking exactly six (6) bytes: two (2) for parameter number and four (4) for
parameter value.
Each parameter table requires its own upload. A block number out of sequence aborts the upload.
Request PDU
Byte 1
Byte 2 Byte 3 Byte 4 Byte 5
Function Code (67) Sub-Code (3) Parameter Table Number Blocking Factor Block Number
Where,
Byte 1: Parameter Support function code 67 (0x43)
Byte 2: Sub-Code 3 for parameter upload
Byte 3: Parameter Table Number: 1-4
Byte 4: Blocking Factor (BF)
5 ≤ BF ≤ 40
Maximum number of parameters packed into a PDU
Example:
Assume 305 parameters, and BF=30
305 = 10*BF + 5
Thus the total number of blocks is 11
The first 10 blocks contain 30 parameters
Block 11, the last block, contains the last 5 parameters
Byte 5: Block Number (0 - N)
Host must start with block 0, the header block
Blocks 1 - N contain parameter data
Total number of blocks, N, returned by he drive in the header defined below
Response PDU: Drive Response Block 0 (Header Block)
Byte 1
Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8 Byte 9 Byte 10
Function Code (67) Sub-Code (3) Block Number Parameter Table Number Parameter Count Blocking Factor Total Blocks CRC
Where,
Byte 3: Block number 0 (header)
Byte 4: Parameter Table Number: 1-4
Byte 5-6: Parameter Count
16-bit integer
Data in high to low byte order
Byte 7: Blocking factor
Byte 8: Total number of blocks not counting the header block
Byte 9-10: CRC
Modbus CRC-16 algorithm
16-bit unsigned integer
Data in high to low order
Computed over ALL parameter data value bytes
Response PDU: Drive Response 1-N (Data Blocks)
Byte 1
Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8 Byte 9 . . .
Function Code (67) Sub-Code (3) Block Number Parameter Number Parameter Value . . .
Byte M-5 Byte M-4 Byte M-3 Byte M-2 Byte M-1 Byte M
Parameter Number Parameter Value
Where,
Byte 3: Block number: 1-N (data)
Bytes 4-5: Parameter number in high to low byte order
Bytes 6-9: Corresponding parameter value in high to low byte order
Bytes M-5 to M: Last parameter number and value needed to complete the block