UNI is the “Universal” protocol utility designed by RACOM. It is not a new SCADA protocol, it can actually process different protocols of different vendors. It supports both the standard MASTER -SLAVE and the MULTI MASTER types of communication. At least one Master is required in the network.
The SCADA protocol to be handled by the UNI has to meet solely the following condition: There has to be an 8 or 16 bit* protocol address in every message generated by a Master station and the address position in all messages has to be the same. The position of address in the reply from an RTU is not relevant, because the reply is always send back to the address where the request originated.
Some SCADA protocols use two byte ASCII address, which is an ASCII representation of an 8 bit address in the hexadecimal format (e.g. “8C” means 8-bit value 0x8C in hex / 140 in decimal notation).
Address bytes for some protocols:
|Mars-A||8th Byte (without local ACK)|