VEGA VEGACOM 557 Profibus FMS - Manual (Page 50)

50 VEGACOM 557 Profibus FMS
Supplement
3 Field bus relating type of communication
relationships
- Master-Master connections
- Master-Slave connections for cyclical
and acyclical data traffic
- Master-Slave connections for cyclical or
acyclical data traffic with Slave initiative
- connectionless communication relation-
ships
4 Connection attributes (open, defined, initia-
tor)
- point-to-point or Multicast/Broadcast
communication
- automatic connection monitoring with
adjustable monitoring interval
5 Local and remote network management
functions
- Context Management
- Fault Management
- Configuration Management
6 Master and Slave instruments, mono or
Multi-Master system configurations
7 Max. 240 bytes of data possible with each
service (protocol overhead not included)
8 Bus structure enables non-reactive cou-
pling and decoupling of stations
Communication relationships
connection-
oriented
connectionless
Broadcast Multicast Master / Master Master / Slave
acyclical cyclical or acyclical
with or without Slave initiative
5.3 Short description of the stand-
ard interfaces RS 232, RS 422
and RS 485
The standard interfaces RS 232, RS 422, RS
485 used in VEGACOM 557, depending on
the version, transmit the data serially and
asynchronously in bit form. Thus, the condi-
tions "0" and "1" are transmitted by defined
voltage levels. Usually, the transition level
corresponds to a logic "1". The respective
levels are specified in the following informa-
tion according to the individual interfaces.
Standard data transmission
0 0 0 0 0 0 0
1 1 1 1
0
1
Data bits
Transition
level
Stop bits
MSB
LSB
Start bit
Transition
level
MSB = most significant bit
LSB = least significant bit
Number of data bits = 8
Overview of all possible communication services