Nivobob
®
1
2
3
4
5
6
7
8
9
10
11
12
NB 3000
gi130109
21
Continuous level measuring system
NB 3000
Technical information / Instruction manual
page G
Electrical installation
Remote Box NB 9000 - Connecting to NB 3000
NB 9000
(see page before)
NB 3000
Unit 1
Recommended Modbus cables:
Cable length <50m (164 ft):
Shielded cable (specifications see page G13)
Cable length >50m (164ft) - 1000m (3270ft):
Twisted pair cable (specifications see page G13)
Notes:
•
Installation of NB 9000 only in Non-Hazardous areas permitted
•
Max. length of network: 1000m (3270ft)
•
Max. 10 units NB 3000 possible
•
Additional use of other signal input and output should be wired in a separate cable.
•
D0, D1 = Modbus lines
NB 3000
Unit 2
NB 3000
Unit x
Termination
resistor OFF
(factory
provided)
Termination
resistor ON
Last unit:
Termination
Resistor must
be switched ON
(see below)
Only if required: Power supply for NB 9000 can be taken from one of
the NB 3000 power supply terminals. Use a separate cable. NB 9000
must then have same supply (AC or DC) as NB 3000.
Biasing network
Setting the Termination Resistor
A termination resistor must be present at both ends of the
modbus network (ca. 150 Ohms between lines D0 and D1).
The biasing network of the NB 9000 implements a
termination resistor at the beginning of the network.
The termination resistor of the last NB 3000 in a network
must be switched on (jumper setting, see drawing).
