Connecting Modbus and LonWorks Networks - FieldServer ...

Translation ChallengesSimple vs Structured VariablesTHE CHALLENGE‣ All Modbus variable types possess a simple structure.‣ This essentially means that one Modbus variablerepresents one value. The exception is when vendorsuse a register to represent 16 binary states.‣ LonWorks consists of a combination of SNVT’s s thathave both simple structures and “Structuredvariables”.‣ Structured variable consists of a variable thatrepresents multiple values, i.e. SNVT_Switch consistsof two values, the state portion representing a binaryvalue, and the value portion representing a percentage.Both are transferred as part of one variable.‣ The challenge is to group data from Modbus thatneeds to be sent as a structured variable inLonWorks, or to split structured variables fromLonWorks into simple Modbus variables.