Profibus Fms Coupling (Sinec L2-Fms) - Siemens SIMADYN D Manual

Communications configuring
3.7

PROFIBUS FMS coupling (SINEC L2-FMS)

PROFIBUS FMS
terminology
3-88
• FDL (Fieldbus Data Link)
Is the definition of PROFIBUS layer 2, defined by EN 50170
(DIN 19245 Part 1)
• FMS (Fieldbus Message Specification)
Is the definition of PROFIBUS layer 7, defined by EN 50170
(DIN 19245 Part 2). FMS defines objects, which are processed using
utilities.
• Client
The client generally issues a task to a utility.
• Server
The server generally accepts a utility task.
• Object directory
The object directory is a list of all objects and their descriptions of a
station which, as server have access for processing using the FMS
utilities. Objects are for example: Data types, variables. Each object is
uniquely identified by a number, the PROFIBUS index. The data type,
possibly an object name, authorization access and possibly a
structure description are included in an object description. The objects
relevant for SIMADYN D communications are variables, which are
processed using the FMS utilities read, write or information report.
• Read
Using the "Read" FMS utility, the client reads the value of a variable
available in the server object directory. The client sends the "Read
variable X" task to the server; the server sends the value of variable X
as response.
• Write
Using the FMS utility "Write", the client changes the value of a variable
which is available in the server object directory. The client sends the
task "Write variable X", together with the new value, to the server; the
server sends a conformation as response.
• Information report
Using the FMS utility "Information report", the server sends the client,
unrequested, the value of a variable which is present in his object
directory (of the server). For this utility, the server is an initiator which
is an exception. The client does not acknowledge this. Using this
utility, a server can simultaneously transmit data to several clients
(broadcast mode).
• Get OV
The FMS utility "Get OV" supplies the client the description of the
objects available in the server object directory. The client sends the
"Get OV object X" task to the server; the server sends the description
of object X as response.
SIMADYN D, as client, generally executes the "Get OV" utility for a
variable once before it executes the first read or write operation. The
System- and communication configuring D7-SYS - SIMADYN D
Edition 12.2003