Data Object Properties
- MODBUS RTU packets are only intended to send data; they do not have the capability to send parameters
- If the ability to send such parameters is needed, one should investigate a BACnet, EtherNet/IP, or other modern protocol
Name | Type | Access | Visual |
Discrete Input | single bit | read-only | |
Discrete Output (Coils) | single bit | read-write | |
Input Registers | 16-bit word | read-only | |
Holding Registers (Registers) | 16-bit word | read-write |
Addressing
- Standard MODBUS RTU node addresses are 1-254, with 0 being reserved for broadcast messages and write only
- The ‘0’ address is rarely used due to the fact that there is no confirmation that the message was properly received at the server node