BRONKHORST HIGH-TECH B.V.
9.17.024
Page 10
2.3 Cables
For connecting instruments to the FLOW-BUS you need shielded cables with at least 3 wires (for data only).
Recommended are twisted wire cables for RS485-communications with 100 or 120 Ohm impedance.
All Bronkhorst High-Tech FLOW-BUS cables have also integrated power-supply wires.
For the use in the EL-FLOW range (non IP-65) it is best to use Shielded (+Foiled) Twisted Pair patch-cables
with RJ45 modular jack connectors (8-pins for data and power-supply connections).
For the use in for example the IN-FLOW range or CORI-FLOW range (IP-65 applications) it is best to use
DeviceNet Drop cables assembled on both sides with male connector M12 – female connector M12 (5-pins for
data and power-supply connections).
In case of powering instruments or transporting data over longer distances Bronkhorst High-Tech offers also
special RS485 FLOW-BUS datacable, with lower voltage-drop.
Bronkhorst High-Tech can advise you when to use this special cable, but for most cases the standard
patch-cables will do well.
If more cables are used in one system, they have to be connected as a daisy-chain. This means that the
total FLOW-BUS system has only one begin and one end.
For connecting instruments to the bus, Bronkhorst High-Tech offers special drop-cables which enable you
to build a daisy chained network of FLOW-BUS modules.
2.4 Termination
For best quality of data transfer FLOW-BUS should be terminated correctly.
Termination can be performed with special termination-connectors, offered by Bronkhorst High-Tech B.V.
At the begin of each FLOW-BUS system there always must be a resistor network as showed above.
This begin-terminator needs to be part of your system. Bronkhorst High-Tech offers special begin-termination
connectors with the resistor network.
This handles correct termination but also gives a defined voltage on the RS485-A and -B line for even more
reliability of the FLOW-BUS system.
Bronkhorst High-Tech advises always to use a termination resistor at the end of the bus in your system .
This end-terminator is also offered by Bronkhorst High-Tech and handles correct termination for the
FLOW-BUS.
Black
End
termination
Begin
termination
Red
0Vdc
Connected
modules
0Vdc
Power
supply
RS485-A
RS485-B
RS485-A
RS485-B
FLOWBUS
