15
Electrical Connection
– continued –
Note
n
The specified max. baud rates and cable lengths are based on empirical values
obtained by GESTRA. In certain cases it may be necessary to reduce the baud rate in
order to ensure operational safety.
n
The type and design of the data cable has a strong influence on the electromagnetic
compatibility (EMC) of the equipment. 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 plug-in unions.
CAN bus voltage supply
To ensure the troublefree operation of the CAN bus system make sure that the voltage supply for all bus
devices is sufficient.
Please use the following table to check the voltage supply of your bus system.
Control units with
voltage supply
Qty.
x
Power output per item
=
Sum
x
6 W
=
W
Please enter data.
Sum 1
=
W
Sensor, transmitter, control
units, operating & display unit
URB 1
Qty.
x
Power consumption per item
=
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 supply the CAN bus with 24 V DC coming from a separate and stabilized safety
power supply unit (e. g. SITOP Smart 24 V 2.5 A).
The power supply unit must be electrically isolated from dangerous contact voltages and must meet 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, Munich
