Endress+Hauser iTEMP TMT 165 FOUNDATION Fieldbus Betriebsanleitung Seite 94

5 Operation
94
Fig. 5-1 FOUNDATION Fieldbus system architecture including associated components (line structure)
FF-HSE = High Speed Ethernet, FF-H1 = FOUNDATION Fieldbus-H1, LD = Linking Device, PS = Fieldbus
Power Supply, SB = Safety Barrier, BT = Bus Terminator
The following possibilities can be realised in respect of system connection:
– A linking device can be used to connect to higher ranking fieldbus protocols (e.g. to the High Speed
Ethernet - HSE) (Control Net)
– An FF-H1 card is required for direct connection to a process control system.
– System inputs are available directly for FF-H1 and FF-H2 (FF-HSE).
The system architecture of the FOUNDATION Fieldbus can be divided into two
subnetworks:
H1 bus system:
In the field, fieldbus devices are connected only via the slower H1 bus system that is
specified following IEC 61158-2. The H1 bus system allows simultaneous feed to the
field devices and data transfer on the two-wire line.
The following points describe some important characteristics of the H1 bus system:
• All fieldbus devices are powered via the H1 bus. Like the fieldbus devices, the power
supply is connected in parallel to the bus line. Devices requiring external power must
use a separate power supply.
• One of the most common network structures is the line structure. Star, tree or mixed
network structures are also possible using connecting components (junction boxes).
• The bus connection to the individual fieldbus devices is achieved by means of a T-
connector or via a spur. This has the advantage that individual fieldbus devices can
be connected or disconnected without interrupting the bus or the bus communication.
• The number of connected fieldbus devices depends on various factors, such as use
in hazardous areas, length of spur, cable types, current consumption of field devices
etc. (see page 87).
FOUNDATION Fieldbus temperature transmitter
Endress+Hauser