Temperature Detection Via Rtd Boxes; Description - Siemens SIPROTEC 4 7SJ61 Manual

Functions

2.14 Temperature Detection via RTD Boxes

2.14 Temperature Detection via RTD Boxes
An RTD box 7XV5662 with 12 measuring sensors in total can be used for temperature detection and are recog-
nized by the input/output device.
Applications
•
In particular, the thermal status of motors, generators and transformers can thus be monitored. Rotating
machines are additionally monitored for a violation of the bearing temperature thresholds. The tempera-
tures are measured by RTD Resistance Temperature Detectors in different locations of the protected
object and forwarded to the device via a 7XV5662 RTD box.

Description

2.14.1
RTD Box 7XV5662
The RTD box 7XV5662 is an external device mounted on a DIN rail. It features 12 temperature inputs and one
RS485 interface for communication with the protection device. The RTD box detects the coolant temperature
of each measuring point from the resistance value of the temperature detectors (Pt 100, Ni 100 or Ni 120)
connected via two- or three-wire cable and converts it into a digital value. The digital values are made avail-
able at a serial interface.
Communication with the Protection Device
The protection device can employ with a RTD-box 7XV5662 via its service port (port C).
Therefore, up to 12 temperature measuring points are available in this way. For greater distances to the
protection device the communication via fiber optic cables is recommended. Alternative communication struc-
tures are shown in Appendix
Processing Temperatures
The transmitted raw temperature data is converted to a temperature in degrees Celsius or Fahrenheit. The
conversion depends on the temperature sensor used.
For each temperature detector two threshold decisions can be performed which are available for further
processing. The user can make the corresponding allocations in the configuration matrix.
Each temperature sensor issues an alarm in case of a short-circuit or interruption of the sensor circuit or if a
sensor is configured but not assigned. Additionally, a group indication is generated across all 6 temperature
sensors of the RTD box (14101
Fail: RTD-Box 1 is generated for RTD1 to RTD6 or 267 Fail: RTD-Box 2 for RTD7 to RTD12.
The following figure shows the logic diagram for temperature processing.
The manual supplied with the RTD-box contains a connection diagram and dimensioned drawing.
182
C Connection Examples dargestellt.
Fail: RTD ). In case of communication malfunctions, the fault indication 264
SIPROTEC 4, 7SJ61, Manual
C53000-G1140-C210-6, Edition 05.2016