ABB ACH 400, User Manual

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ACS/ACH 400 Direct N2 Bus Interface 2-1
Chapter 2 – Overview of the N2
Connection
This chapter describes the general features of
the N2 Bus. For more detailed information on
the use of the N2 Bus, please consult the
appropriate Johnson Controls documentation.
Introduction
The N2 Bus protocol is a master - slave type
serial communication protocol, used by the
Johnson Controls Metasys system. In the
Metasys architecture the N2 Bus connects point
interfaces and remote controllers to Network
Control Units (NCUs).
Also the N2 Bus can be used to connect ACS/
ACH 400 drives to the Johnson Controls
Companion product line.
This chapter is not intended to describe the
protocol in detail, it is intended to describe the
use of the N2 Bus with the ACS/ACH 400
drives’ connection.