PMD85Electronic differential pressure liquid level measurement system

Equipped with metal measuring film or ceramic sensor, intelligent overload resistance, and functional monitoring,HARTCommunication,Multi point linearity and temperature compensation.

Working principle

PMD85Used for measuring the liquid level, volume, or mass of liquids in pressurized tanks. The system consists of two sensors and oneComposed of a transmitter. One of them

Sensors are used for static pressure measurement (high pressure), with two sensors used forTop pressure measurement (low pressure). Based on the above two digital quantities or simulations

Measurement pressure value, transmitter calculationgetLiquid level value (electronic differential pressure). The process pressure causes the metal process isolation diaphragm of each sensor to form

Change, inside the overall sensorFill the liquid to transmit pressure to the circuit resistance bridge (semiconductor technology). Measurement and pressure related bridge transmissionElectricity generation

Pressure,And perform subsequent calculations.

Technical features

Compared to traditional differential pressure measurement systems with pressure taps or capillaries, electronic differential pressure measurement systems eliminate the following:Question:

L eliminates measurement bias caused by changes in medium temperature or ambient temperature, suitable for long-term exposure to vacuum (negative)Liquid level measurement under working conditions.

Eliminating condensation and blockage in the pressure tapping tube.

L saves the cost of high insulation measures required to prevent freezing of the pressure tapping tube (in terms of installation energy).

Eliminating the frequent leakage of pipelines and connecting parts in traditional measurement systems.

High repeatability and long-term stability.

lEach sensor has high reference measurement accuracy: up to±0.075%Platinum type: ±0.05%

The liquid level measurement system has been simplified, thereby improving product applicability and reliability.

The new electronic differential pressure measurement system structure and design minimize safety risks to the greatest extent possible.

Due to the shortened installation time and maintenance downtime, as well as reduced spare parts requirements, the overall cost for users has been loweredOperating costs of the body.

lEnsure that the overload resistance can reach the nominal pressure10times

Compared with diaphragm sealing systems with capillaries, the thermal effect is significantly reduced.

Technical parameters

Measurement range ·Minimum measurement range:-10KPa~+10KPa；Maximum measurement range:-0.1MPa~1MPa

Accuracy ·The comprehensive error (including linearity, repeatability, and hysteresis) is better than0.1%

·Reference measurement accuracy of each sensor: up to the set range±0.1%

Long term stability·Better than every year0.1%F.s

Allowtemperature ·medium temperature （-40～150）℃

·Environmental temperature（-40～85）℃

·storage temperature（-40～85）℃

Temperature influence·be relative to25℃ every10KPa≤0.05%(or higher requirements agreed upon)

Allow environmental humidity ·100%RH

Damping ·0~40SContinuing Adjust

Signal output·4-20mALinear output two-wire beltHARTCommunication protocol

Start time·3SNo preheating required

Vibration impact·2g 1000HZ±0.05%g

Impact resistance·50g 11mesc

Power supply impact·≤ Output range0.005%V

Load characteristics ·Corresponding power supply voltage impedance50Ω~1000Ω (see figure)

Power supply ·Non hazardous area:12~45V DC

·Ex iaExplosion proof zone:12（13）~30 VDC

Sensor range ratio ·10:1Continuously adjustable zero point and reversible100%migrate

Electromagnetic compatibility characteristics ·Compliant withIEC801standard

Installation location impact ·Non horizontal installation generates<0.25KPaZero point error,Calibration can be obtained by adjusting the zero point without affecting the measurement accuracy

Electrical connection ·M4Screw grounding terminal is suitable for0.5~1.5mmEquipped with cable sealing shell suitable for outer diameter6~8mm

Process connection materials ·Stainless steel304Or special requirements agreed upon

Contact with medium ·Sensor corrugated diaphragm: stainless steel316 96%Alumina ceramics

Partial materials·Ceramic sensor sealing ring: Fluororubber or special requirements agreed upon

Not connected to the medium·Shell: Die cast aluminum strip with epoxy resin coating

Touch some materials ·Stainless steel nameplate304Intermediate liquid silicone oil or anaerobic oil in sensors

·Fasteners made of stainless steel

On site monitor ·Five digit digital LCD display

Explosion proof grade ·explosion-prooftypeEx dⅡC T5； Intrinsically safe typeEx iaⅡC T5

outline structure

Transmitter structure

Sensor casing

Load characteristics

Electrical connection

Instrument installation

Installation bracket

Order Selection Table