Safety notes
ASCII | 3964R | RK512
4
Safety notes
Safety notes for the planning stage
Observe the general rules for PROFIBUS components when planning the SPI 3 installa-
tion.
Please observe the following to avoid risk to personnel and damage to equipment and to
ensure that the SPI 3 functions correctly:
Safety regulations
– Observe the guidelines in the VDE 0100 regulations for hand-
ling electrical components,
– Observe the applicable safety and accident prevention reg-
ulations.
Assembly personnel
The SPI 3 must only be installed or de-installed by qualified techni-
cal personnel with appropriate electrotechnical qualifications.
PROFIBUS standard
Observe the guidelines in the PROFIBUS standard EN 50 170.
Bus cable
Bus wiring should only take place using special screened, twisted
pair PROFIBUS cable. The high data transfer rates can only be
guaranteed with the correct cable type.
Cable lengths
Refer to the manual for the DP master for information on maximum
cable lengths for PROFIBUS.
Terminating resistors
Terminating resistors must be used if the SPI 3 is installed at the
beginning or end of the PROFIBUS cable segment. In this case,
you should use PROFIBUS connectors which contain an integrat-
ed terminating resistor. We recommend you to use connectors
from ERNI and Siemens. If the bus is incorrectly terminated, this
can lead to errors in data transfer or to damage to other stations on
the bus.
Bus connectors
You should only use commercially available PROFIBUS connec-
tors for connecting the bus. We recommend you to use connectors
from ERNI and Siemens.
Cable screen
Screened cables are less sensitive to interference due to electro-
magnetic fields. With screened cables, the interference currents
are led to ground through the screening rail, which is electrically
connected to the case. To ensure that the interference currents
which flow through the screening do not themselves interfere with
other devices, it is important to provide a low impedance connec-
tion to the protective ground. Observe the following rules for the
screens of the PROFIBUS cable and the serial interface cable:
– The braiding of the screening should have a degree of cov-
erage of more than 80 %.
