Mounting and Commissioning
3.2 Checking Connections
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
309
RTD Box / I/O 2 Extension Module
If you are using RTD boxes or the I/O 2 extension module for temperature measurement, please check their
connections and transmission parameters such as bus number, IP address etc.
For further information, please refer to the operating manual of the RTD boxes.
Please observe that detector input 1 (RTD1) of the first RTD-box is assigned for ambient or coolant temperature
of the overload protection.
Connection of temperature sensors directly to the device (only 7SK805/7SK806 ):
In principle, 2-wire or 3-wire connection of temperature sensors is possible. Siemens recommends, however,
to use only 3-wire connections. When using 2-wire connections, short circuit links must be used e.g. for RTD 2
between D3 and D5.
Figure 3-21 Example: connection of temperature sensor RTD 1 (3-wire connection) and RTD 2 (2-wire con-
nection) to clip D1 to D5
RTD-Box to RS485
If one or two 7XV5662-xAD RTD-boxes are connected, check their connections to the port (port B).
Verify also the termination: The terminating resistors must be connected to 7SK80 (see margin heading „Ter-
mination“).
For further information refer to the operating manual of 7XV5662-xAD. Check the transmission settings at the
temperature meter. Besides the baud rate and the parity the bus number is also important.
For connection of RTD-box(es) proceed as follows:
• For connection of 1 RTD box 7XV5662-xAD: Bus number = 0 (to be set on 7XV5662-xAD).
• For the connection of 2 RTD boxes 7XV5662-xAD: bus number = 1 for the 1st RTD box (to be set on
7XV5662–xAD for RTD 1 to 6), bus number = 2 for the 2nd RTD box (to be set on 7XV5662-xAD for RTD 7
to 12).
Termination
The RS485 interface is capable of half-duplex service with the signal A/A' and B/B' with a common relative po-
tential C/C' (GND). Verify that only the last device on the bus has the terminating resistors connected, and that
the other devices on the bus do not. The jumpers for the terminating resistors are on the interface module
RS485 or on the PROFIBUS RS485. The terminating resistors can also be connected externally. In this case,
the terminating resistors located on the module must be disabled.
In case ofa bus extension, it must be ensured that only the last device on the bus has the terminating resistors
connected, and that the other devices on the bus do not.
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