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TOP ELECTRONIC PRESSURE SENSOR FOR SMS TENSIOMETERS - SKM 850

The SKM 850 pressure sensor is built for field use and has a 0 to -999 HPa (mbar) measuring range.

The SKM 850 sensor has its own temperature correction (-10°C /+50°C).

The sensor is light (85 grs) and small. You can easily take it with you to your field.

The SKM 850 sensor is compact, waterproof and is built for outdoor as well as indoor use.

The SKM 850 sensor will be strongly fixed to any tensiometer.

The SKM 850 sensor exists in two versions : diffrential voltage (ref. SHM 850T) or current loop output (SKM 850C2).

You can choose between ordering the sensor alone or fixed to a tensiometer (all lengths are possible).

Key Advantages

LOW PRICE
TEMPERATURE COMPENSATION
QUICK : immediate placing on any tensiometer tube
MONITORING by connection to a data logger

Disadvantages
Measurements more sensitive to temperature than with the SKT 850 model

TECHNICAL CHARACTERISTICS

Measuring range : 0 Hpa to -999 Hpa.
Accuracy : better than 1% of full scale.
Pressure sensor : differental pressure type with integrated temperature compensation.
Offset : factory calibrated (SKM 850C2 sensor only ; each sensor is delivered with an individual calibration certificate).
Measuring principle : by piercing the needle case on the upper part of the tensiometer. The case can be placed on any existing tensiometer (manufactured by SDEC France or any other manufacturer).
Also fixable : on a combined tensiometer & lysimeter tube, ref. TENSIONIC (let us know when ordering).
Fastening system : simply pushed on the top of the tensiometer tube (needle trough silicone stopper).
Output: On cable across nickel stuffing box.
Power supply : direct current; +6 to +15 Volts. Protection : the sensor is electronically protected against polarity reverse (SKM 850C2 model).
Temperature compensation : -10°C to +50°C.
Sensor case : Polycarbonate box (black colour).
Dimensions : Ø = 40 mm.
Weight : 85 grammes.
Operating temperature : -5°C à + 50°C.(with anti-freeze).
Storage temperature : -20°C à + 60°C.(without water inside sensor).

Ask for a quotation

SKM 850 Qty
Cable length (standard 2m) Qty
SMS tensiometer tubes :
Length (depth + 10cm) Qty
Qty
Anti-algae STM 21310 (20cc)
Qty

The standard set

The SKM 850 is delivered alone. The tensiometer tubes, SMS type (ref. SMS 2000, SMS 2000S), must be ordered separately

You also need

. Tensiometer tubes. You can choose between the standard tensiometer tubes (ref. SMS) and themicrotensiometers with flexible tubes, or the combinedlysimeter & tensiometer, ref. Tensionic. . Anti-algae liquid, ref. STM 21310 to avoid algae developpement.

Is the measurement taken in air or water ?

The tensiometer tube is full of water but there is some air captured underneath the stopper. The part which is connected to the pressure sensor is meant to measure the air pressure in the tube and must therefore dip into this air and not into water.

How is the sensor powered ?

By the battery supply of the datalogger.

Is there a risk of air leak ?

No, the silicon stopper is selfsealing. The SKM 850 sensor can be left on the tube for as long as you need without consequences on the air pressure in the tube.

Which type of output should I choose ?

You can choose between a differential voltage or current loop output. This choice depends on you data logger input. Usually, for cable length lower than 50 m, we recommend the choice of a voltage output (requires a stabilized power supply). For cable length longer than 50 m, you must choose a current loop output (suitable for cables of hundreds of meters).