Instruction manual

SITRANS TW
126 A5E00054075-05
Installation and commissioning
6.3 Electrical connection
• The electrical connection (1-4, figure 2, page 83) is made by four removable
screw-type connectors. The maximum cable cross section is 2.5mm². The wires
may not be stripped more than 10 mm. Solid wire or strands with end ferrules
must be used.
• Cables carrying dangerous voltages and cables carrying safe voltages must be
laid separately or doubly insulated.
• The pin assignment for input, outputs and power supply is shown in figure 19,
page 127. The different versions for the input wiring of the sensor are shown in
Chapter 6.4, page 129.
• In devices with “intrinsically safe” type of protection, the blue cable housing must
be mounted tight on the input plug on completing installation as a strain relief for
the input cables.
• There is no need to pay attention to polarity when connecting the power supply
to terminals 13 and 14. The device is reverse polarity protected.
• Terminal 12 must be connected to the PE conductor for safety reasons.
• The power supply plug (terminal 12 to 14) may never be plugged in or removed
when the power is switched on. The device must be protected by a mains switch
close by which is appropriately labeled.
WARNING
The specifications of the examination certificate valid in your country must be
observed.
Laws and regulations valid in your country must be observed for the electrical
installation in explosion hazardous areas. In Germany these are for example:
- Working reliability
- Regulations for installing electrical equipment in hazardous areas DIN EN
60079-14.
A distance of 50 mm must be kept between the connections of the intrinsically
safe circuit and the non intrinsicallysafe connections by isolated assembly or
partitions (use the supplied blue cable housing for input plug).
The potential of the input circuit related to the PE conductor must be limited to
50V if the device is supplied from the mains.
A PE conductor must be connected to the device. The following points should be
considered in the electrical installation of the PE conductor:
- The PE conductor terminal may be a potential source of danger if not installed
properly.
The specifications of the EC test certificate must be observed when connecting
sensors, leads and devices for use in Ex areas. The specifications regarding
permissible external capacitances, inductances and the permissible values for
U
m
*) must be observed in particular.
*) U
m
is the maximum voltage (AC or DC) which, according to EN 50020, may be applied to non-
intrinsically safe connecting parts without affecting the intrinsic safety.