FT8511 series magnetostrictive liquid level gauge

The FT8511 series magnetostrictive level gauge is based on the principle of magnetostriction and is a two-wire intrinsic safety level gauge. It is used for accurate and reliable process level measurement and tank capacity measurement and control in the measurement and control fields of petroleum, petrochemical, chemical, food, and other industries.

　　measuring principle

The magnetostrictive sensor is the core of the magnetostrictive liquid level monitoring system, and the core sensitive element of the sensor (magnetostrictive wire) has the characteristics of high strain value and strong electrical (magnetic) mechanical wave conversion ability, which can convert small magnetic vector changes into mechanical waves. The sensor consists of two parts: a stainless steel rod (with built-in magnetic extension wire) and a floating ball (with built-in rare earth permanent magnet). When the electric pulse generated by the pulse generator in the electronic component is transmitted along the magnetostrictive wire inside the steel pipe, the electric pulse current simultaneously generates a circular magnetic field perpendicular to the magnetostrictive wire and propagates along the magnetostrictive wire at the speed of light.

When the electric pulse ring magnetic field meets the inherent magnetic field of the float, the two magnetic fields interact, generating instantaneous torque and forming a mechanical torque wave pulse on the magnetostrictive line. The mechanical torque wave is transmitted back to the electronic component at a certain speed. Electronic components pick up pulses, and by measuring the time difference between the emitted electrical pulse and the returned torque wave pulse, the height or level of the measured liquid surface can be accurately calculated.

　　characteristic

Modular design: Instrument sensors and electronic units can be interchangeable and universal, facilitating spare parts and maintenance.

Detachable installation: Suitable for various application scenarios, easy to control and observe.

Can be used in conjunction with external float type float level gauges: more diverse applications.

HART communication: Comes with industrial field two-wire 4-20mA HART communication.

On site button calibration: It can directly calibrate high and low liquid levels through the two buttons at the top of the unit, which is convenient and fast to use.

　　Typical applications

Finished oil storage tank

Gas station oil tank

Process tank leakage detection

Various chemical reagents

Water and sewage treatment

Other high-precision liquid level detection

　　performance index

Measurement equipment level: CAT I level, transient rated voltage 1500V, cannot be used for levels other than CAT I level

Output: 4-20mA HART protocol, software adjustable current output direction

Measurement method: can be set as level/distance measurement method by software

Power supply: 12-35VDC; Requirement for intelligent communication: power supply of 15-35VDC

Power: less than 0.5W

Accuracy: ≤ 0.1% FS or 1mm (whichever is greater)

Resolution: ≤ 0.04% FS or 0.4mm (whichever is greater)

Repeatability: ≤ 0.04% FS or 0.4mm (whichever is greater)

Linear correction: Software selectable 10 point nonlinear correction (if necessary)

Temperature effect: 0.1%/10 ℃ (18 ℉)

Load resistance: Output circuit load resistance capacity of 600 Ω at 24VDC

Environmental temperature: T5: -40 to+70 ℃ (-40 to 158 ℉); T6: -40 to+60 ℃ (-40 to 140 ℉) (The influence of medium temperature on ambient temperature cannot exceed the instrument's requirements for ambient temperature)

Response time:<2 seconds

Delay: Adjustable from 1 to 90 seconds (software adjustable)

Range: 0-5m (hard pole), 0-20m (soft cable)

Dead zone: Upper dead zone ≤ 1/2 of the float height,

Dead zone pole type: one floating ball height; Cable type: 250mm~450mm

Maximum process temperature: -40 to+400 ℃ (see probe performance indicators for details)

Maximum process pressure: 10MPa (see probe performance indicators for details)

Split cable length: The longest split cable is 3 meters

Electrical interface: M20X1.5 (optional 3/4 "NPT)

Process connection: NPT thread installation (standard, optional BSPT), flange installation (optional)

Explosion proof rating: ExiaIIBT5/T6 Ga and Exd IIBT5/T6 Gb

Protection level: Compliant with IP67 protection standard

Certification: CMC, PCEC/NEMSI. For other certifications, please consult the manufacturer

　　Probe indicators

Note: When the user selects the FS48 sensor and uses a temperature>120 ℃, it is best to use a high-temperature resistant insulation bracket, such as a modified phenolic resin (electric wood) material insulation bracket

FT8511 wiring diagram

The FT8511 series liquid level gauge belongs to the intrinsic safety type instrument. When installed in hazardous environments, certified safety barriers need to be added to its power supply circuit. Both single and double barriers can be used, but the connection method is different. The system wiring diagram in Figure 4.5 shows examples of single barrier installation and double barrier installation. Please consult our company or our agent for certified safety barrier products. Please refer to the instructions for the use of safety barriers for grounding requirements. The maximum impedance of cables, loads, and safety barriers under 24VDC power supply is 600 Ω. The level gauge is powered by a certified safety barrier, and the requirements for the safety barrier of this level gauge are:

Uo=28VDC

Io=93mA

Po=0.65W

Co=0.6uF

Lo=15mH

The safety parameters of the instrument are as follows:

Ui=30V

Ii=99.01mA

Pi=0.74W

Ci=2nF

Li=50uH

The wiring of the explosion-proof on-site system does not require safety barriers, but all cables are required to be in explosion-proof tubes.

In the instrument current loop, it should be ensured that the load on the instrument power supply side is greater than 250 ohms. If necessary, a 250 ohm resistor should be directly added to the power supply side to facilitate smooth communication.

　　Installation requirements for FT8511

The installation, use, and maintenance of the product should comply with the relevant provisions of the product installation, commissioning, and use instructions, GB50257 "Code for Construction and Acceptance of Electrical Equipment in Explosive and Fire Hazardous Environments", GB3836.15 "Electrical Equipment for Explosive Gas Environments Part 15: Electrical Installation in Hazardous Areas (excluding Coal Mines)", and GB3836.13 "Electrical Equipment for Explosive Gas Environments Part 13: Maintenance of Electrical Equipment for Explosive Gas Environments".

When installing instruments, they should be kept as far away as possible from vibration sources, high temperature environments, corrosive air, and any places that may cause mechanical damage. If the requirements cannot be met, please replace the instrument with a new component. The ambient temperature should be between -40 and 70 ℃ (-40 and 158 ℉).

The instrument installation area requires lightning protection devices to prevent lightning strikes.

It is prohibited to use single component ambient temperature sulfurized sealant inside the instrument casing. This substance often contains acetic acid, which will corrode electronic components. Special two-component sealant (non corrosive) should be used.

The instrument casing is equipped with grounding terminals, and users should ensure reliable grounding during installation and use. When used for non-metallic cans, a standard ground should be provided on site and cannot be connected to the power ground.

The electrical interface should be equipped with cable sealing joints with a protection level of IP65 that meet the requirements of GB4208 standard to ensure reliable sealing and prevent damage to the instrument electronic unit caused by water ingress or other corrosive gases.

Do not disassemble the sensor or loosen the sealing nut to avoid probe leakage.

The installation of sensors should avoid material flow or inlet/outlet ports. If there are no other installation locations, protective covers or partitions should be added.

The installation of threads or flanges should be firmly connected to the container, reliably sealed, and have good electrical contact. Except for the connection, other parts of the sensor should not come into contact with the container to ensure the normal movement of the float.

During the installation of the probe, there should be no ferromagnetic materials within a range of 200mm from the probe.

When the user selects the FS48 sensor and the operating temperature is>120 ℃, it is best to use a high-temperature resistant insulation bracket.

When installing hard rod sensors, the installation space should be considered, with a distance of at least 200mm from the tank wall. Cable sensors should be straightened after installation, with a distance of at least 300mm from the tank wall to avoid the float hitting the wall.

In situations where there is significant mixing, airflow, and material flow fluctuations inside the test container, in addition to avoiding direct mechanical damage to the sensor, indirect mechanical damage such as long-term fatigue of the sensor material should also be considered. Therefore, it is recommended to install protective measures such as bottom support or ground anchor fixation for the sensor.

Instruments installed according to explosion-proof standards must be equipped with explosion-proof stuffing boxes or explosion-proof steel pipe sealing joints certified by GB3836.1 and GB3836.2 explosion-proof standards for electrical interfaces.

The instrument circuit installed according to intrinsic safety standards must be equipped with safety barriers certified by GB3836.1 and GB3836.4 explosion-proof standards.

The ripple of 24VDC power supply shall not exceed 100mV.

The instrument connection cable shall comply with the requirements of IEC60245/60227 standard. It is recommended to use armored shielded 3-core cables with an outer diameter of no more than 12mm. The cable conductor material is copper, and the cross-sectional area of the conductor is 0.13-2.1mm2 (AWG14-26). The insulation strength of the cable is 1500V. Long distance unshielded cables cannot be used in parallel with AC power cables.

When using and maintaining on site, the principle of "no opening with power on" must be followed, and it is recommended to shut off the power for 10 minutes before operation.

　　FT8511 Typical Installation