User manual

RS232-ADC16/24
6 Commands
The device uses a MODBUS similar command set, assuming all parameters as
16-bit values.
The following commands are provided.
6.1 Read Holding Registers
A contiguous block of 16-bit software holding registers can be read at once.
Addressing starts at 0, count is greater than 0 and less or equal 125.
Command : Read Holding Registers
Function code 1 byte 0x03
Start address 2 bytes 0x0000 to 0xFFFF
Register count 2 bytes 0x0000 to 0x007D
If the function succeeds the response contains the read registers.
Response : Read Holding Registers
Function code 1 byte 0x03
Byte count 1 byte (Register count) * 2
Register data (Register count) * 2 bytes
Otherwise an error response is send.
6.2 Read Input Registers
This function is the equivalent to Read Holding Registers corresponding to input
registers.
Command : Read Input Registers
Function code 1 byte 0x04
Start address 2 bytes 0x0000 to 0xFFFF
Register count 2 bytes 0x0000 to 0x007D
If the function succeeds the response contains the read registers.
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