Data in a Modbus device is referenced by register numbers. What each register contains, and the format for analog registers, is defined by the device developer.
Register Type | Decimal | Hex |
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Start | End | Start | End |
---|
Discrete Output Coils | 1 | 9999 | 0 | 270E |
Discrete Input Contacts | 1 | 9999 | 0 | 270E |
Analog Input Registers | 1 | 9999 | 0 | 270E |
Analog Output Holding Registers | 1 | 9999 | 0 | 270E |
- Note that the addresses are offset by 1, because register 1 has address 0.
- Some devices support extended registers, with the maximum register number being 65536 = 2^16.