Installing the SPI 3
11
MODBUS RTU | SPI 3 | Trebing & Himstedt
Connecting up to a fieldbus device with serial interface (MODBUS
slave)
Note!
To ensure that the SPI 3 functions without errors, you should use a
screened cable for connecting to the serial fieldbus device.
– Ensure that the Sub-D connector for the serial interface uses the pin assignments
shown in »Technical specifications« on page 27 (connect the cable screen to the
case of the sub-D connector).
– Attach the sub-D connector for the serial interface to the serial interface socket
on the SPI 3.
Connecting up to the PROFIBUS
Note!
You should only use commercially available PROFIBUS connectors for
connecting to the bus. We recommend the use of connectors from ERNI and
Siemens.
If the SPI 3 is installed at the beginning or end of the PROFIBUS cable
segment, you should use PROFIBUS connectors which contain an integrated
terminating resistor. We recommend using connectors from ERNI and
Siemens.
To ensure that the SPI 3 functions without errors, you must ground the
screen of the PROFIBUS cable.
– Ensure that the PROFIBUS connector uses the pin assignments shown in
»Technical specifications« on page 27.
– Attach the PROFIBUS connector to the PROFIBUS interface socket
on the SPI 3
and secure the connector with the retaining screws.
Setting the PROFIBUS address
Note!
The SPI 3 only updates its PROFIBUS address during a restart. Set the
PROFIBUS address on the SPI 3 before switching on the power, or turn off
the power briefly after changing the PROFIBUS address.
You should only use addresses between 01 and 99.
– The PROFIBUS address is set with the two rotary switches.
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