Analog Output; Heating System - GE Hydran 201 i Instruction Manual

Chapter 2 • Hydran 201Ti Intelligent Transmitter
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 201Ti.
• The oil temperature behind the valve on which the H201Ti is mounted.
Note: This temperature is always lower than the oil temperature at the top of the
transformer tank.
• The thermal regulation of the H201Ti's temperature.
Regardless of the oil or ambient temperature, the H201Ti 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 H201Ti'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.
2-14 Rev. 6, March 2011 Part 17997