4 MG.10.P2.22 - VLT is a registered Danfoss trademarkThis manual is intended to be used for bothinstruction and reference. It only brieflytouches on the basics of the Modbus proto-col whenever necessary to gain anunderstanding of the Modbus RTU optioncard for the VLT 6000.This manual is also intended to serve as aguideline when you specify and optimize yourcommunication system. Even if you are anIntroductionAbout ThisManualWhat YouShouldAlready KnowAssumptionsThis manual provides comprehensiveinstructions on the installation and set up ofthe Modbus RTU option card for theVLT 6000 Adjustable Frequency Drive tocommunicate over a Modbus network.The VLT 6000 Modbus RTU option card isdesigned to communicate with any controllerthat supports the interfaces defined in thisdocument. It is assumed that you have fullknowledge of the capabilities and limitationsof the controller.This manual assumes that you have acontroller that supports the interfaces in thisdocument and that all the requirementsstipulated in the controller, as well as theVLT 6000 Adjustable Frequency Drive, arestrictly observed, along with all limitationstherein.experienced Modbus programmer, it issuggested that you read this manual in itsentirety before you start programming sinceimportant information can be found in allsections.References VLT ® 6000 Installation, Operation andInstruction Manual, Danfoss Grahamdocument number 23-6108-00.(Referred to as the VLT 6000 OperatingInstructions in this document.)For specific information on installation andoperation of the adjustable frequency drive,refer to the VLT 6000 Operating Instructions.