Safety notes
6
Trebing & Himstedt | SPI 3 | MODBUS RTU
Safety notes
Safety notes for the planning stage
Observe the general rules for PROFIBUS components when planning the SPI 3
installation.
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 handling electrical
components,
–
Observe the applicable safety and accident prevention
regulations.
Assembly personnel
The SPI 3 must only be installed or de-installed by qualified
technical personnel with appropriate electrotechnical
qualifications.
PROFIBUS standard
Observe the guidelines in the PROFIBUS standard IEC
61158.
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 PROFIBUS norm 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 integrated terminating resistor. We recommend
use of 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
connectors for connecting the bus. We recommend using
connectors from ERNI and Siemens.
Cable screen
Screened cables are less sensitive to interference due to
electromagnetic 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 connection to the
protective ground. Observe the following rules for the
screens of the PROFIBUS cable and the serial interface
cable:
