GE Hydran 201i, Инструкция по эксплуатации

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Chapter 2 • Hydran 201T
i
Intelligent Transmitter
2-14 Rev. 6, March 2011 Part 17997
The sensor signal is in microvolts (µV). It is first divided in two scales; then, these two
signals go through the analog/digital converter and finally the two digital values are read
by the microprocessor. The two scales are:
• Low scale, which ranges from 0 to 4,000 µV.
• High scale, which ranges from 0 to 40,000 µV.
The thermistor signals are in ohms (

; 3,000

at 25 °C). These two signals also go
through the analog/digital converter and are then read by the microprocessor.
2.5.2 Analog Output
The isolated (up to 2,000 V RMS) analog 4–20 mA current output can supply a load
ranging from 0 to 500

(10 V maximum). It is used with a SCADA system.
For details on how to use the analog output, see Appendix G; for wiring details, see
Table D-6 on page D-3.
2.6 HEATING SYSTEM
The recommended operating temperature range of the Hydran 201 sensor is 15 to 65 °C (59
to 149 °F). The sensor temperature is a function of:
• The ambient air temperature surrounding the Hydran 201T i .
• The oil temperature behind the valve on which the H201T i is mounted.
Note: This temperature is always lower than the oil temperature at the top of the
transformer tank.
• The thermal regulation of the H201T i ’s temperature.
Regardless of the oil or ambient temperature, the H201T i is designed (heating and passive
cooling) to maintain the sensor temperature between 25 and 45 °C (77 and 113 °F), if the
set-point (
Temp SetPoint parameter in the Temperature;DynOil Sampl submenu; see
Section 4.5.3 on page 4-17) is set to the recommended temperature of 35 °C (95 °F).
The H201T i ’s microprocessor measures the temperature and controls the heating power. A
fail alarm is triggered (if on; see the FaultTrig. parameters in Section 4.5.7.3 on page 4-24)
when the sensor temperature is outside the operating limits.