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2 Functions
2.32
RTD-Box
Up to 2 thermoboxes with a total of 12 measuring points can be used for temperature
detection and evaluated by the protection device. In particular they enable the thermal
status of motors, generators and transformers to be monitored. Rotating machines are
additionally monitored for a violation of the bearing temperature thresholds. The tem-
peratures are measured in different locations of the protected object by employing
temperature sensors (RTD = Resistance Temperature Detector) and are transmitted
to the device via one or two 7XV566 thermoboxes.
2.32.1 Functional Description
Interaction with the
The ambient or coolant temperature can be fed via the thermobox to the overload pro-
Overload Protec-
tection function of the device. For this purpose the required temperature sensor must
tion
be connected to sensor input 1 of the 1st thermobox (corresponds to RTD 1).
RTD-box 7XV56
The thermobox 7XV566 is an external device mounted on a standard DIN rail. It fea-
tures 6 temperature inputs and one RS 485 interface for communication with the pro-
tection device. The thermobox 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 a two- or three-wire line and converts it to a digital value. The digital
values are made available at a serial port.
Communication
The protection device can communicate with up to 2 thermoboxes via its service port
with the Protection
(port C).
Device
Up to 12 temperature measuring points are in this way available. For greater distances
to the protection device, a fibre optic link is recommended. Possible communication
structures are shown in the appendix.
Temperature Evalu-
The transmitted temperature raw values are converted to a temperature in degrees
ation
Celsius or Fahrenheit. The conversion depends on the temperature sensor used.
For each measuring point two thresholds decisions can be performed which are avail-
able for further processing. The user can make the corresponding allocations in the
configuration matrix.
An alarm is issued for each temperature sensor in the event of a short-circuit or inter-
ruption in the sensor circuit.
The following figure shows the logic diagram for temperature processing.
The manual supplied with the thermobox contains a connection diagram and dimen-
sioned drawing.
192
7UM61 Manual
C53000-G1176-C127-3
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