Wiring Devices With Profibus Pa - Siemens SITRANS F M TRANSMAG 2 Operating Instructions Manual

Profibus Communication
B.2 Wiring devices with Profibus PA
B.2

Wiring devices with Profibus PA

Lid over terminals for power supply may not be removed! Use only certified measuring
instruments!
The Profibus PA variant of the SITRANS F M Transmag 2 differs from the HART variant with
the 4-20 mA output in the bus interface and the omission of the digital output 2. The basic
functions of the device including the operation and display remain basically the same.
The Transmag 2 terminals 7 and 8 are reserved for the Profibus PA connection.
● 7: PA wire 1. This device is polarity independent
● 8: PA wire 2. This device is polarity independent
The PA interface is polarity independent, so the wires can be connected arbitrarily.
PA supports LINE, DROP, STAR topology and a combination of the three.
Figure B-1
Figure B-2
Shielding
● Only use shielded cables for the PROFIBUS connection. Any connection polarity is
● The shield must be laid to cover all assigned terminal boxes, distributors up to the coupler
● The shield must be connected and fixed with the shield clamp.
● To achieve the best EMC performance, the unshielded wires should be as short as
92
WARNING
PA wiring
PA wiring with T-connector
possible.
or link.
possible, 3-4 cm.
SITRANS F M TRANSMAG 2
Operating Instructions, 11/2009, A5E00102775-07