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21 Annex
21.2.2
Voltage supply to the bus with DC 5 V from a JUMO digiLine hub
Bus cabling in line topology
Sensor type
JUMO digiLine pH/
ORP/T
JUMO ecoLine O-DO
JUMO ecoLine NTU
a
The maximum length of the bus line depends on the number and type of connected sensors and on how
they are distributed along the bus line. Due to the widely varying current consumptions of the different
sensor types, it is difficult to state a generate value that will apply for all installation situations. In case of
doubt, it is advisable to carry out a voltage drop calculation during the planning phase (cf. Chapter 21.2.4
"Voltage drop calculation", page 142).
b
Stub line from a JUMO digiLine hub or Y-distributor up to a sensor with JUMO digiLine electronics
138
The line length specifications in this subchapter apply when supplying JUMO
ecoLine sensors and sensors with JUMO digiLine electronics with DC 5 V from
a JUMO digiLine hub. In this case, the JUMO digiLine hub must be supplied with
DC 24 V. The slide switch on the JUMO digiLine hub must be set to the position
for DC 24 V as the input voltage. The electronics of the JUMO digiLine hub gen-
erate the bus supply voltage of DC 5 V internally and supply its outputs with this
voltage.
In the line topology, the bus line must be provided with terminating resistors at
both ends wherever possible, in order to avoid transmission interference
through reflections. If JUMO ecoLine sensors are used, however, terminating re-
sistors must not be employed. You should therefore use terminating resistors
only in a JUMO digiLine bus without JUMO ecoLine sensors. M12 terminating
connectors are available from JUMO for the bus termination.
⇨
Chapter 4.4 "Accessories", page 21
Terminating resistors can be activated via DIP switch on the options board for
serial interface RS422/485.
⇨
Chapter "Optional board interfaces", page 64
Max. length of
a
bus line
200 m
200 m
Max. length of
Max. number of con-
b
stub lines
nectable sensors
10 m
6
10 m
6
Comment
-
Bus termination
is not permissi-
ble
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