KROHNE OPTISONIC 3400 EN - Manual (Page 119)

DESCRIPTION OF HART INTERFACE
9
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OPTISONIC 3400
www.krohne.com 11/2013 - 4002037702 - HB OPTISONIC 3400 -en-R02
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