52
MOVITRAC
®
31.. PROFIBUS Fieldbus Interface
4
The PROFIBUS-FMS
Interface
Service Access Points (LSAP, RSAP)
Service access points form the interface between the application layer (layer 7) and the data link
layer (layer 2) of a PROFIBUS station across which messages are transferred.
From the point of view of the inverter, the
LSAP (Local Link Service Access Point) is the local
service access point of the MOVITRAC
®
31.. inverter where the message crosses the interface
between layer 2 and layer 7. Consequently, the
RSAP (Remote Service Access Point) as seen by
the MOVITRAC
®
31.. inverter is the service access point of the FMS master where the message
crosses the interface between layer 2 and layer 7 of the FMS master.
As the inverter does not know the
RSAP, it is entered automatically only as the link is being estab-
lished. The CRL for the inverter therefore contains the entry
All.
Station Address of the FMS Master (RADR)
The station address of the FMS master wishing to communicate with the inverter via this commu-
nications relationship is entered in the RADR (Remote Address) field. As the address of the FMS
master can change, it is only entered as the link is established. The CRL for the inverter therefore
contains the entry
All.
Flow Control Counters (SCC, RCC, SAC, RAC)
The flow control counters indicate the maximum number of services running in parallel. The
following table shows the meaning of the individual CRL entries.
Control Interval Times (ACI, CCI)
These CRL entries specify the time intervals used in the monitoring of a communications link, i.e.
the inverter checks whether any data was transferred during the specified time interval. If this is not
the case, communication is aborted. The time interval applies to both cyclic (Cyclic Control Interval,
CCI) as well as acyclic links (Acyclic Control Interval, ACI).
Protocol Data Unit Size (max PDU Size)
This CRL entry indicates the maximum size of the protocol data unit (max PDU size). It comprises
four entries as per following table.
Supported FMS Services (Features Supported)
This CRL entry specifies which services the MOVITRAC
®
31.. inverter supports in the relevant
communications relationship.
Abbreviation
Meaning
SCC
Send Confirmed Request Counter
Number of parallel confirmed services send
RCC
Receive Confirmed Request Counter
Number of parallel confirmed services receive
SAC
Send Acknowledged Request Counter
Number of parallel unconfirmed services send
RAC
Receive Acknowledged Request Counter
Number of parallel unconfirmed services receive
Abbreviation
Meaning
Send HiPrio
Maximum size of the protocol data unit for high priority send messages
Send LoPrio
Maximum size of the protocol data unit for low priority send messages
Rec. HiPrio
Maximum size of the protocol data unit for high priority receive messages
Rec. LoPrio
Maximum size of the protocol data unit for low priority receive messages
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