Physical Layer; H1 Bus - AUMA AUMATIC AC 01.2 Manual

General information regarding Foundation Fieldbus
2.3.

Physical layer

2.3.1.

H1 bus

8
Figure 2:
The lowest bus level, the physical layer, is based on IEC standard 61158-2. This
layer defines how the physical connection to the fieldbus network as well as the data
transmission are to be performed.
Foundation Fieldbus uses two systems for the communication. The low H1 version
for communication and direct connection of the field devices, the fast HSE version
based on Industrial Ethernet within the DCS and for connecting Remote Operations
Management (ROM) systems.
The following summary gives a brief overview of the features and functions of the
H1 bus. For detailed information, refer to the various Application Guides of the
Fieldbus Foundation (e.g. AG-140, AG-163, AG-181, FD-043).
Data transfer: Manchester coding
Data transfer rate 31.25 kbit/s (default setting, cannot be modified).
Requirements for perfect communication: Sufficient power supply for the field
devices, i.e. minimum 9 volts for each device. Software tools are available for
network planning, calculating the resulting currents and terminal voltages on
the basis of network topology, the cable resistance, and the supply voltage.
TM
E.g. DesignMATE
Field device connection via H1 version. The Foundation Fieldbus Power Condi-
tioner is connected to the bus line in the same way (parallel) as a field device.
Field devices supplied by additional supply sources have to be connected to
these sources as well.
The maximum power consumption of current consuming devices within H1
networks must be lower than the electric power supplied by the Foundation
Fieldbus Power Conditioner.
Network topologies: Line topology; when using junction boxes or segment bar-
riers, also star, tree or a combination of these topologies.
Device connections: Typically via short spurs to enable connection/disconnection
of the devices without impairing communication to other users.
Maximum length of a spur: 120 m, depending on the number of spurs used as
well as the number of devices per spur.
AC 01.2/ACExC 01.2 Foundation Fieldbus
, available via www.fieldbus.org.
Actuator controls