Chapter 6 – Communication
Installation and Start-up Guide for NPBA-01
6-4
The communication references presented in Table 6-1 can be divided
into two groups - those used for process control (Master 1), and those
used for supervision and diagnostics (Master 2). CRs 5, 6 and 7 are
reserved for diagnostics. However, any master can activate any CR,
but multiple masters cannot have the same CR initialised at the same
time.
CR 2 is used in Broadcast (the message is read by all stations,
including masters) and Multicast communication. This message type is
also called the Information Report. It is possible to send the same PPO
message to every station or a certain group of stations, or specify a
different message for each station. The format is as follows:
Station No. defines the station or stations that the information is
intended for. Station No. 127 is a universal station number
comprehending all stations on the link.
Offset (PROFIBUS Parameter
No. 914) indicates the location of the PPO for the particular station,
while
PPO Type (PROFIBUS Parameter No. 904) specifies the type of
PPO message used (see Table 6-2, page 6-7 for PPO types and their
composition).
CR 3 is used in cyclic read operations of parameters and process data.
This CR uses PPOs.
CR 4 is a cyclic write service for parameters and process data. This CR
uses PPOs.
CR 5 allows Master 2 to read parameters and events.
CR 6 allows Master 2 to read cyclically from a PPO message without
the Parameter Identification part.
CR 7 is an acyclic CR for Master 2. This CR supports read, write and
events services.
CR 8 and higher have been reserved for acyclic communication.
Note: CRs 3 to 7 are profile-specific – for the use of these CRs, a
profile number is required. For drives it is 3.
Station No.
Offset
PPO Type
PPO1
. . .
PPOn
