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Installation and Start-up Guide for NPBA-01
6-1
Chapter 6 – Communication
Overview
This chapter describes the contents of the PROFIBUS messages used
for the communication with the ACS 600.
General
The NPBA-01 PROFIBUS Adapter Module supports the PROFIBUS-
FMS and PROFIBUS-DP protocols. PROFIBUS-FMS has a slower
transfer rate than PROFIBUS-DP, but it enables acyclic services not
available with PROFIBUS-DP. The PROFIBUS-DP is ideal for high-
speed cyclic I/O data transfer.
PPO Messages
Both the PROFIBUS-FMS and PROFIBUS-DP protocols use so-called
PPOs
(Parameter/Process Data Objects) in cyclic communication. See
Table 6-2, page 6-7 for the different PPO types and their composition.
Service Access Points
The services of the PROFIBUS Data Link Layer (Layer 2) are used by
both PROFIBUS-FMS and PROFIBUS-DP through Service Access
Points (SAPs). Both protocols use an individual subset of the services:
in FMS, SAPs are used for addressing the logical communication
relationships. In DP, precisely defined functions are assigned to
individual SAPs.