Operating instructions

VLT
®
2800, VLT
®
6000 HVAC and VLT
®
8000 AQUA Modbus RTU
Overview
■ VLT 2800, VLT 6000 and VLT 8000 with Modbus RTU
The frequency converter communicates in Modbus
RTU format over an EIA-485 (formerly RS-485)
network. Modbus RTU allows access to the frequency
converter’s Control Word and Bus Reference.
The Control Word allows the Modbus master to control
several important functions of the frequency converter:
• Start
• Stop the frequency converter in several ways:
Coast stop
Quick stop
DC Brake stop
Normal (ramp) stop
• Reset after a fault trip
• Run at a variety of preset speeds
• Runinreverse
• Change the active setup
• Control the frequency converter’s two built-in relays
The Bus Reference is commonly used for speed control.
It is also possible to access the parameters, read
their values, and, where possible, write values to
them. This permits a range of control possibilities,
including controlling the frequency converter’ssetpoint
when its internal PID controller is used.
MG.10.S2.02 - VLT is a registered Danfoss trademark
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