Mounting and Commissioning
3.2 Checking Connections
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
324
RTD Box / I/O 2 Extension Module
If you are using an RTD box or the I/O2 extension module for temperature measurement, check their connec-
tions and the transmission parameters, if necessary, such as the bus number, IP address etc.
For more information, see the operating instructions enclosed with the RTD box.
Please observe that sensor input 1 (RTD1) of the RTD box is reserved for input of the ambient temperature or
coolant temperature of the overload protection.
Connection of temperature sensors directly to the device (only 7SK805/7SK806 ):
It is generally possible to connect temperature sensors with 2-wire or 3-wire technology. Siemens recommends
using only the 3-wire technology. When using the 2-wire connection, a jumper must be installed e.g. for RTD 2
between D3 and D5.
Figure 3-21 Example: Connection of the temperature sensors RTD 1 (3-wire connection) and RTD 2 (2-wire
connection) at terminal D1 to D5
RTD-Box to RS485
If a 7XV5662-6AD10 RTD box is connected, check its connections to the interface (port B).
Verify also the termination: The terminating resistors must be connected to 7SK80 (see margin heading „Ter-
mination“).
For more information on the 7XV5662-6AD10, please refer to the enclosed device manual. Check the trans-
mission parameters at the RTD box. In addition to the baud rate and the parity, the bus number is important, too.
When connecting a 7XV5662-6AD10 RTD box, set the following bus numbers at the RTD box: :
• Bus number = 1 for RTD 1 through 6
• Bus number = 2 for RTD 7 through 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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