KROHNE OPTISONIC 7300 EN - Manual (Page 112)

9
DESCRIPTION OF HART INTERFACE
112
OPTISONIC 7300
www.krohne.com 09/2012 - 4001102303 - MA OPTISONIC 7300 R03 en
9.3.3 Multi-Drop connection (3-wire connection)
Connection of 2-wire and 4-wire devices in the same network. In order that the current output of
the signal converter is working continuously active, an additional third wire must be connected
to the devices in the same network. These devices must be powered via a 2-wire loop.
1 Primary Master
2 HART
® modem
3 HART ® signal
4 2-wire external devices (slaves) with 4…20 mA, addresses > 0, powered by current loop
5 Signal converter terminals A (C)
6 Signal converter terminals A- (C-)
7 Connection of active or passive 4-wire devices (slaves) with 4…20 mA, addresses > 0
8 Load ≥ 250 Ω (Ohm)
9 Secondary Master
10 Power supply