23 (0X17) Read/Write Multiple Registers" Function - Toshiba TOSVERT VF-AS3 Instruction Manual

3.7. "23 (0x17) Read/Write Multiple Registers" function

The "Read/Write Multiple Registers" service is used for the IO Scanning service.
Request format:
Byte
0 Function Code = 0x17
1 Read Starting Register Hi(0)
2 Read Starting Register Lo(0)
3 Number of Read Registers Hi (0)
Number of Read Registers Lo (2 – 9)
4
5 Write Starting Register Hi (0)
6 Write Starting Register Lo (0)
7 Number of Write Registers Hi (0)
8 Number of Write Registers Lo (2 - 9)
9 Byte Count (B = 2 × Number of Write Registers)
10 First Write Register Data Hi
11 First Write Register Data Lo
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B+8 Last Write Register Data Hi
B+9 Last Write Register Data Lo
Response format:
Byte
0 Function Code = 0x17
1 Byte Count (B = 2 × Number of Points)
2 First Read Register Data Hi
3 First Read Register Data Lo
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B Last Read Register Data Hi
B+1 Last Read Register Data Lo
Exception response format:
Byte
0 Function Code = 0x97
Exception Code =
01 (Illegal Function)
1 02 (Illegal Data Address)
03 (Illegal Data Value)
04 (Slave Device Failure)
If the communication number that doesn't exist is read, device returns 0x8000.
When you use this Modbus request with I/O scanning service, the value is written to RAM.
Please set the "00" for Read Starting Address and Write Starting Address
Meaning
Meaning
Meaning
Notes
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