KT-550 Moisture & Temperature Transmitter

Unique Features Specification Application Moisture in Oil Unique Features

• Reliable

• • Patented product, compatible with various oils
  • Sensor lifespan up to 10 years
  • High efficiency: <5mA@24Vdc
  • Unique grounding protection and signal sampling unit

• Accurate

• • Imported sensing chip, unique temperature compensation algorithm
  • Water activity accuracy: ±2%; temperature accuracy: ±0.3°C
  • Traceable calibration certificate from national metrology institute

• Robust

• • IP66 protection, full stainless-steel body
  • Reverse polarity protection, industrial isolation
  • Wide power input: 9–36VDC

• Easy to Use

• • G1/2” BSP standard interface, easy installation
  • Local digital output and calibration port
  • Built-in calibration curves for various oils

Specification

Temperature
Measuring range	-40 … 120 °C
Accuracy (@25°C)	±0.3°C
Resolution	0.1°C
Water Activity
Measuring range	0 … 1aw
Accuracy	0…0.6: ±0.02aw;
	0.6…1: ±0.03aw
Resolution	0.001aw
Dissolved Water (calibrated per oil type)
Measuring range	0…2000ppm or customized
Accuracy	±10% or 10ppm (whichever is greater)
Resolution	1ppm
Dielectric Constant
Measuring range	1…6
Accuracy	±0.1
Resolution	0.001
Free/Emulsified Water
Measuring range	0…10% or customized
Accuracy	±0.5 %
Resolution	0.10%
General
Mechanical interface	G1/2” ISO
Signal output	RS485 MODBUS RTU
Ambient temperature	-40 … +80 °C
Allowed oil temp	-40 … +80 °C
Probe pressure	20bar (customized on request)
Probe material	316 & 304 stainless steel
Protection class	IP65
Power supply	10–28V DC
Supply current	<20mA@DC24V
Transmitter weight	200g
Total package weight	270g
Package dimensions	172*117*53 mm (carton)
Connector	GX16, 5-pin
Cable	4-core, 2 m, UL20866 4×22AWG
EMC standards	EN61326-1, EN61000-3, EN61010 Class B

Application

• Oil fields, oil refining
• Wind, hydro, thermal, nuclear power, power transmission
• Engineering machinery
• Aviation, marine
• Railway, highway transportation
• Iron and steel, metallurgy
• Oil storage, fuel stations
• Industrial production lines

Applicable Oils：

• Lubricating oil
• Hydraulic oil
• Gear oil
• Engine oil
• Fuel oil
• Insulating oil
• Turbine oil
• Various light oils, heavy oils, etc.

Moisture in Oil

1. Water Activity (aw, 0…100%)

The ratio of actual moisture content to saturated moisture content in oil at the current temperature (range: 0…1 aw).

• 0 aw: no water in oil
• 1 aw (100% RH): dissolved water is saturated; free water will precipitate.

1. Dissolved Water (ppm, Parts Per Million)

Mass or volume ratio of dissolved water in oil.

• Mass ratio: mg/kg
• Volume ratio: μl/L

According to GB/T7600-2014, the unit is mg/L. Conversion: 58 ppm × 0.86 g/ml = 50 mg/L (0.86 g/ml = oil density).

1. Free Water & Emulsified Water (%)

Forms when dissolved water reaches saturation (aw=1). Expressed in % (e.g., 2% = 2 parts water in 100 parts oil-water mixture).

Dissolved Water

Water present at the molecular level. Related to base oil type, additives, and temperature. Oil appears clear before saturation.

Free Water

Formed when dissolved water precipitates (due to cooling) or external water intrudes. Water droplets sink to the tank bottom.

Emulsified Water

Formed when free water is intensely agitated or sheared, creating micro-droplets suspended in oil. Oil turns cloudy/white and causes severe system damage.

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