SITRANS LH100, transmitter for hydrostatic level

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The pressure transmitter SITRANS LH100 is a submersible sensor for hydrostatic level measurement.

The pressure transmitter measures the liquid levels in tanks, containers, channels and dams. The SITRANS LH100 pressure transmitters are available for various measuring ranges and with explosion protection as an option.

A junction box and a cable hanger are available as accessories for simple installation.

Область применения

SITRANS LH100 pressure transmitters are used in the following branches, for example:

Shipbuilding
Water/waste water supply
For use in unpressurized/open vessels and wells

Дизайн

The pressure transmitter has a built-in ceramic sensor which is equipped with a Wheatstone resistance bridge.

These pressure transmitters are equipped with an electronic circuit fitted together with the sensor in a stainless steel housing. In addition, the connecting cable contains a vent pipe which is equipped with a humidity filter to prevent the build-up of condensation.

The diaphragm is protected against external influences by a protective cap.

The sensor, the electronics and the connecting cable are housed in an enclosure with small dimensions.

The pressure transmitter is temperature-compensated for a wide temperature range.

Функции

SITRANS LH100 pressure transmitter, mode of operation and connection diagram

On one side of the sensor (1), the diaphragm (5) is exposed to the hydrostatic pressure which is proportional to the submersion depth. This pressure is compared with atmospheric pressure. Pressure compensation is carried out using the vent pipe (3) in the connecting cable. The vent pipe is equipped with a humidity filter which prevents the build-up of condensation in the vent pipe.

The hydrostatic pressure of the liquid column acts on the diaphragm of the sensor and transmits the pressure to the Wheatstone resistance bridge in the sensor.

The output voltage of the sensor is applied to the electronic circuit where it is converted into an output current of 4 to 20 mA.

The protective conductor connection/equipotential bonding (4) is connected to the enclosure.

Интеграция

It is generally recommended that the connecting cable of the SITRANS LH100 transmitter is connected to the junction box, which can be ordered separately, and secured with the cable hanger, also available separately. The junction box has to be installed near the measuring point.

If the medium is anything other than water, it is also necessary to check compatibility with the specified materials of the transmitter.

Junction box 7MF1572-8AA, open, schematic diagram

Measuring point setup, generally with junction box 7MF1572-8AA and 7MF1572-8AB cable hanger

Чертеж

SITRANS LH100 pressure transmitter, dimensions in mm (inch)

Junction box, dimensions in mm (inch)

Cable hanger, dimensions in mm (inch)

Особенности

Compact design
Simple installation
Small error in measurement (0.3 %)
Degree of protection IP68

Технические данные

Pressure transmitter SITRANS LH100 (submersible sensor)
Mode of operation
Measuring principle	piezo-resistive
Input
Measured variable	Hydrostatic level
Measuring range	Max. permissible operating pressure
0 ... 3 mH₂O (0 ... 9 ftH₂O)	1.5 bar (21.8 psi) (corresponds to 15 mH₂O (45 ftH₂O))
0 ... 4 mH₂O (0 ... 12 ftH₂O)	1.5 bar (21.8 psi) (corresponds to 15 mH₂O (45 ftH₂O))
0 ... 5 mH₂O (0 ... 15 ftH₂O)	1.5 bar (21.8 psi) (corresponds to 15 mH₂O (45 ftH₂O))
0 ... 6 mH₂O (0 ... 18 ftH₂O)	1.5 bar (21.8 psi) (corresponds to 15 mH₂O (45 ftH₂O))
0 ... 10 mH₂O (0 ... 30 ftH₂O)	3.0 bar (43.5 psi) (corresponds to 30 mH2O (90 ftH2O))
0 ... 20 mH₂O (0 ... 60 ftH₂O)	5.0 bar (72.5 psi) (corresponds to 50 mH₂O (150 ftH₂O))
0 ... 0.3 bar	1.5 bar
0 ... 0.4 bar	1.5 bar
0 ... 0.5 bar	1.5 bar
0 ... 0.6 bar	1.5 bar
0 ... 1 bar	3.0 bar
0 ... 2 bar	5.0 bar
Output
Output signal	4 ... 20 mA
Measuring accuracy	According to IEC 60770-1
Error in measurement at limit setting including hysteresis and reproducibility
Measuring range
0 ... 3 mH₂O (0 ... 9 ftH₂O or 0 ... 0.3 bar)	0.5% of full-scale value (typical) 1.0% of full-scale value (maximum)
for all other measuring ranges	0.3% of full-scale value (typical) 0.6% of full-scale value (maximum)
Effect of ambient temperature
Measuring range	Zero and span
3 mH₂O (9 ftH₂O or 0.3 bar)	0.45 %/10 K of full-scale value
4 ... 6 mH₂O (12 ... 18 ftH₂O or 0.4…0.6 bar)	0.45 %/10 K of full-scale value
> 6 mH₂O ( > 18 ftH₂O or > 0.6 bar)	0.3 %/10 K of full-scale value
Long-term stability
Measuring range	Zero and span
3 mH₂O (9 ftH₂O or 0.3 bar)	0.4% of full-scale value/year
4 ... 6 mH₂O (12 ... 18 ftH₂O or 0.4…0.6 bar)	0.25% of full-scale value/year
> 6 mH₂O ( > 18 ftH₂O or > 0.6 bar)	0.2 % of full-scale value/year
Rated conditions
Ambient conditions
Process temperature	-10 ... +80 °C (14 ... 176 °F)
Storage temperature	-40 ... +80 °C (-40 ... +176 °F)
Degree of protection according to IEC 60529	IP68
Design
Weight
Pressure transmitter	≈ 0.2 kg ( ≈ 0.44 lb)
Cable; maximum cable length 100 m (330 ft)	0.025 kg/m (≈ 0.015 lb/ft)
Electrical connection	Cable with 3 conductors, vent pipe and integrated humidity filter
Material
Seal diaphragm	Al₂O₃ ceramic, 96%
Enclosure	Stainless steel, mat. no. 1.4404/316L
Gasket	FPM (standard) EPDM (optional)
Connecting cable	PE-HD (standard) PE-LD (in the case of versions with EPDM seal, suitable for drinking water applications)
Auxiliary power
Terminal voltage on pressure transmitter U_B	10 ... 33 V DC 10 ... 30 V DC for transmitter with intrinsic safety explosion protection
Certificates and approvals
Drinking water approval (ACS)	applied for
Drinking water approval (WRAS)	1403525
EAC	№ TC RU C-DE.ГБ05.В.00732 OC НАНИО «ЦСВЭ»
Underwriters Laboratories (UL)	2014-11-17 - E344532
The device is not subject to the pressure equipment directive (PED 2014/68/EU)
Explosion protection
Intrinsic safety "i"	IECEx SEV 14.0003 SEV 14 ATEX 0109
Marking	II 1 G Ex ia IIC T4 Ga

Junction box
Application	for connecting the transmitter cable
Design
Weight	0.2 kg (0.44 lb)
Electrical connection	2 x 3-way (28 to 18 AWG)
Cable entry	2 x Pg 9
Enclosure material	polycarbonate
Vent pipe for atmospheric pressure
Screw for cable strength cord
Rated conditions
Degree of protection according to IEC 60529	IP65

Cable hanger
Application	for mounting the transmitter
Design
Weight	0.16 kg (0.35 lb)
Material	Galvanized steel, polyamide

Дальнейшая информация

Determination of the measuring range for media with a density of ≠ 1000 kg/m³ (medium ≠ water)

Calculation of the measuring range:

p = ρ x g x H

with:

ρ = density of medium

g = local acceleration due to gravity

H = maximum level

Example:

Medium: Diesel fuel, ρ = 850 kg/m³

Acceleration due to gravity: 9.81 m/s²

Start-of-scale: 0 m

Maximum level: 6.0 m

Cable length: 10 m

Calculation:

p = 850 kg/m³ x 9.81 m/s²x 6.0 m

p = 50 031 N/m²

p = 500 mbar

Transmitter to be ordered:

7MF1572-1FA11

Plus, if required, junction box 7MF1572-8AA and cable hanger 7MF1572-8AB