Sensor Temperature; Heater Plate (Dynamic Oil Sampling System) - GE Hydran M2-X Instruction Manual

Hydran* M2-X Instruction Manual
• Sensor temperature: A thermistor is included within the sensor to measure
its temperature.
Note: The Hydran M2-X also measures the heater plate temperature using
thermistors mounted inside the heater plate; see Section 2.5.
2.4.3

Sensor Temperature

For the recommended operating temperature range of the sensor, see the
technical specifications in Appendix A. The sensor temperature is controlled by the
dynamic oil sampling system of the heater plate (see Section 2.5). The external
factors that affect the sensor temperature are:
• Ambient air temperature surrounding the Hydran M2-X.
• Oil temperature behind the valve on which the Hydran M2-X is mounted
Note: A system fault alarm condition is detected when the sensor temperature is
outside the operating limits. For more information, see Section 3.3.2.6 and Section 6.3.

2.5 Heater Plate (Dynamic Oil Sampling System)

The Dynamic Oil Sampling (DOS) system uses controlled heating and passive
cooling to stimulate oil movement in front of the sensor to ensure a representative
sample is supplied to the sensor at all times.
Heating is achieved using heating resistors mounted on the internal side of the
heater plate. The heating power is controlled by a time-proportioning algorithm.
This algorithm modulates the temperature around the desired set point. For more
information, see Section 3.2.4.
Note: Detection of an open thermistor shuts the heating power off.
Note: The dynamic oil sampling system temperature is limited to 50°C (122°F). A
thermal fuse with an 80°C (176°F) rating is located on the base plate and a FUI located
on the power supply board to provide protection against any fault from the control
circuitry
MA-029 Rev. 1.0, 30-Jul-18
Page 33