Promag 53 PROFIBUS-DP/-PA 4 Wiring
Endress+Hauser 49
Maximum overall cable length
The maximum network expansion depends on the type of ignition protection and the
cable specifications. The overall cable length is made up of the length of the main cable
and the length of all spurs (>1 m). Note the following points:
• The maximum permissible overall cable length depends on the cable type used.
• If repeaters are used the maximum permissible cable length is doubled.
A maximum of four repeaters are permitted between station and master.
Maximum spur length
The line between distribution box and field device is described as a spur.
In the case of non ex-rated applications the max. length of a spur depends on the
number of spurs (>1 m):
Number of field devices
In systems that meet FISCO in the EEx ia type of protection, the line length is limited a
max. of 1000 m.
A maximum of 32 stations per segment in non-explosive areas or a maximum of 10 sta-
tions in an Ex-area (EEx ia IIC) are possible. The actual number of stations must be
determined during the project planning.
Bus termination
The start and end of each fieldbus segment are always to be terminated with a bus ter-
minator. With various junction boxes (not ex-rated) the bus termination can be activated
via a switch. If this is not the case a separate bus terminator must be installed. Note the
following points in addition:
• In the case of a branched bus segment the device furthest from the segment connec-
tor represents the end of the bus.
• If the fieldbus is extended with a repeater then the extension must also be terminated
at both ends.
Shielding and grounding
(see Cable specifications PROFIBUS-DP Page 46)
Further information
General information and further notes regarding the wiring can be found in the Operat-
ing Instructions BA 198F/00/en “Field communications - PROFIBUS-DP/-PA:Guides for
project planning and commissioning”.
Type A 1900 m
Type B 1200 m
Number of spurs 1 ... 12 13... 14 15... 18 19... 24 25... 32
Max. length per spur 120 m 90 m 60 m 30 m 1 m
To Next Page
Loading...
