Comem Dti And Edti; Operating Principle - ABB Comem DTI Instruction Manual

TRANSFORMER COMPONENTS
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2. Comem DTI and eDTI

2.1 Operating principle

The Comem DTI family are devices which use PT100 temperature
probes for constant monitoring of transformer temperatures in 4
points: three on the transformer winding columns and one on the
machine's magnetic circuit.
If the transformer malfunctions, causing its temperature to rise,
Comem DTI unit generates an alarm signal. If the temperature
reaches danger levels the unit generates a second intervention
level. Moreover, a switch can manage the fan.
Comem eDTI version has one port of serial communication RS485
which allows the connection of the measurement data, control
and programming of the device to acquisition system (PC, PLC,
SCADA, etc.). Modbus RTU is the protocol used (see specific
manual for instruction).
A Windows software is available for a management of the device
with complete function of control, storing data and recording
alarm. In addition, it is available an analogue settable output 0-20
mA or 4-20 mA with scale FROM -30°C to +200°C.
The devices type Comem DTI and Comem eDTI allow the control
and the visualization of temperature read with probe type RTD
PT100.
For each channel of measure are available two levels (alarm and
trip) that actives the commutation of the relative output relay for
signaling at distance or for disabling the machine under control.
In the front panel there are a double three-digit display that
shows the temperatures, the status of the alarm of the
measurement channels and five buttons for the programming.
The instrument can control the ventilation, storing maximum
values and trip alarms.
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