Toshiba Tosvert VF-S15

E6582051
- 59 -
8. Modbus TCP
8.1. Header format
Byte
Description
Comments
0
Transaction
identifier
high order
Same transaction ID is returned from Modbus TCP server.
Fixed at 0 if it is not required.
1
low order
2
Protocol
identifier
high order
This identifier always equals 0.
3
low order
4
Length of data
high order Number of bytes after the Unit ID (Byte 6). The value of the high
order should be “0”, because the frame length is always less
than 256 bytes.
5 low order
6
Unit ID (Destination identifier)
Chose from Unit ID described in Section 8.2.
7
Modbus request function code
Chose from Function code described in Section 8.3.
8.2. Setting of Unit ID
The Unit ID (destination identifier) is used to access inverter Modbus TCP servers:
Unit ID
Modbus TCP server
Accessible data
0-248 Inverter (VF-S15/AS3) Inverter parameter
Device identification of inverter
251
Communication module
(this product)
Device identifications of module
8.3. List of Modbus functions supported
Function code
Function name
Description
Size of data
03 (0x03)
Read Holding Register
Read N output words
63 words max.
06 (0x06)
Write Single Register
Write one output word
-
16 (0x10)
Write Multiple Registers
Write N output words
63 words max.
43 (0x2B)
Read Device Identification
Identification
-