GESTRA NRS 1-40, Original Installation Manual

Page: 17 / 40

17
Note
n
The max. baud rates and cable lengths indicated above are based on empirical values
obtained by GESTRA. In certain cases it may be necessary to reduce the baud rate in
order to ensure troublefree operation.
n
The design of the data cable has a strong influence on the eletromagnetic immunity
(EMC). Take special care when connecting the equipment.
n
If you do not use the control cable assemblies connect the connectors and jacks
for the control cables as indicated in the assignment diagram for sensor connector
unions.
CAN bus voltage supply
To ensure troublefree operation the CAN bus system must be supplied with sufficient voltage.
Please use the following table to check the voltage supply of your bus system.
Control units with
voltage supply
Qty.
x
Power rating per equipment = Sum
x
6 W = W
Please enter data!
Sum 1 = W
Measuring transducers,
transmitters, control units,
operating & display unit URB 1
Qty.
x
Power rating per equipment = Sum
x
3 W = W
Operating & display unit URB 2
x
5 W = W
Please enter data!
Sum 2 = W
If sum 2 exceeds sum 1, the CAN bus voltage must be supplied by a separate, stabilised safety power
supply unit (e.g. SITOP smart 24 V, 2.5 A) with 24 V DC.
The power supply unit must be electrically isolated from dangerous contact voltages, meeting at least
the requirements on double or reinforced isolation acc. to DIN EN 50178 or DIN 610101 or
DIN EN 607301 or DIN EN 60950 (safe isolation).
The power supply unit must be provided with an overcurrent protective device in accordance with
EN 610101.
Attention
If a safety power supply unit (e.g. SITOP smart, 24 V, 2.5 A) is used for the voltage supply
of the CAN bus do not tap the supply voltage from the terminals 1 and 5 of the GESTRA
control devices.
SITOP smart is a registered trademark of Siemens AG, München
Electrical Connection
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