YD9820 axis vibration transmitter

1Basic parameters

Vibration range: up to 1000μm(p-p)；

● Gap voltage: 9~11VDC

● External probe: coaxial cable interface

● Temperature drift: ≤0.05/℃

● Working temperature: preamplifier;-20～+85℃, probe;-20～+150℃

● Supply voltage:+24VDC,Maximum operating current ≤50mA

Maximum load:750Ω

Frequency response:4.0~4000Hz(±3dB)

● Buffer output: 1~15VDC

● Linear error: ＜1％Fs

● Range:User selected

Explosion proof grade:ExiaII BT6

2Other parameters

● Probe specifications:

Conventional Φ 5mm or Φ 8mm probe

Typical Probe Structure Diagram

image2.1φ8Armored probe

image2.2 F8Reverse installation probe

● Product factory marking

A complete transmitter system should include a front transmitter, probe, and extension cable. Generally, it is required that the transmitter, probe, and extension cable should be matched and used in a one-to-one manner, and should not be misconnected; Our company's transmitters and extension cables of the same specifications and models can be interchanged! On the factory calibration sheet, the complete set of front transmitters, probes, and extension cables are numbered, allowing users to quickly find the corresponding front transmitters, probes, and extension cables for a complete set of sensors.

The model and number of the front transmitter should be prominently displayed on the surface of the front transmitter housing.

The model and number of the probe and extension cable are sealed in a transparent heat shrink sleeve near the high-frequency joint on the cable.

Users can match the system according to the factory calibration results by comparing the various models and numbers indicated on the factory calibration sheet with the labels on the product. It is generally required to perform calibration checks on sensors before use, especially when the usage conditions are different from the factory calibration conditions, and especially when the measured material is different from the calibration material grade indicated on the factory calibration sheet, recalibration must be carried out.

1Gap between probe installation

When installing the probe, the linear measurement range of the sensor and the variation of the measured gap should be considered. Usually, when measuring vibration, the installation gap of the probe is set at the linear midpoint of the sensor.

When measuring displacement, the installation clearance should be determined based on the change in displacement direction. When the displacement changes in the direction away from the probe end, the installation gap should be set at the linear proximal end; On the contrary, it should be set at the linear far end.

Method for adjusting the installation gap of the probe: Connect the probe, extension cable, and preamplifier, power on the sensor system, monitor the output of the preamplifier with a multimeter, and adjust the gap between the probe and the measured surface.

Note:By measuring the output voltage of the preamplifier to determine the installation gap, there may be a false impression that when the probe head has not yet exposed the installation hole, the metal around the installation hole may cause the output of the preamplifier to be equal to the voltage or current output value corresponding to the installation gap.

image1 Correct or incorrect installation distance of probe

2Installation of extension cables

1) The extension cable is one of the main components connecting the probe and the preamplifier. During the use of extension cables, if they are too long or too short, they should not be cut or extended arbitrarily, otherwise it may cause serious sensor out of tolerance or malfunction!

When coiling extension cables, due to the material, it is necessary to avoid cable breakage caused by a small coiling radius.

When selecting, it should be ensured that the sum of the length of the extension cable and the length of the probe cable is greater than the distance from the probe installation location to the preamplifier installation location, and usually the preamplifier is centrally installed on the same side of the machine.

3Installation of transmitter

The requirements for the working environment of a transmitter are much stricter than those of a probe. It is usually installed in a location far away from hazardous areas, and its surrounding environment should be free of corrosive gases, dry, with minimal vibration, and the ambient temperature should not differ much from room temperature. To ensure the safe and reliable operation of the transmitter, a dedicated transmitter installation box should be used.

4Connection of transmitter system

The system connection includes electrical connections between sensor probes, extension cables (if any), transmitters, and monitoring instruments to form a functional measurement system. The probe, extension cable, and transmitter are connected using standard high-frequency connectors, while the transmitter and instrument are usually connected using multi-core shielded cables. The transmitter is connected using a three core shielded cable (one of which serves as a backup), according to16AGInstructions for multi-core shielded cables, usually with the red wire connected to the power supply（+24VEnd), yellow wire connected to signal output（IoutEnd). To avoid confusion and connecting the wrong wires, the color should be consistent when wiring. The shielding layer of the shielded cable needs to be connected to the signal ground at a single point at one end of the monitoring instrument.

5. The influence of the tested material on the measurement results

1) Sensor characteristics(This refers to sensitivity)It is related to the resistivity and permeability of the tested object. When the tested object is a magnetic material (such as ordinary steel, structural steel, etc.), due to the simultaneous existence of magnetic and eddy current effects, and the magnetic effect is opposite to the eddy current effect, it is necessary to offset some of the eddy current effect, which reduces the sensitivity of the sensor; When the measured object is a non-magnetic or weakly magnetic material (such as copper, aluminum, alloy steel, etc.), due to the weak magnetic effect, the eddy current effect is relatively strong, so the sensitivity of the sensor is high.

Copper:14.9V/mm

aluminium14.0V/mm

stainless steel(1Cr18Ni9Ti)：10.4V/mm

45Steel No.:8.2V/mm

40CrMosteel: 8.0V/mm（Factory calibration materials）

Note:Before leaving the factory, the sensor system is calibrated using 40CrMo material specimens by default. Only the tested material of the same series as it can be recalibrated according to the steps described in Section 1 of Chapter 3 when the composition of the tested material differs significantly from that of 40CrMo. Otherwise, it may cause significant measurement errors.

Because the shafts of most steam turbines, blowers, and other equipment are used40CrMoThe sensor system is made of materials or materials that are close to it, therefore40CrMoThe material undergoes factory calibration and is suitable for most measurement objects.

2）The influence of residual magnetic effect on the surface of the measured object on the measurement results

The residual magnetic effect formed during material processing, as well as uneven quenching, uneven hardness, and uneven crystal structure, can all affect the characteristics of sensors,API670The standard recommends that the residual magnetic field on the surface of the tested object should not exceed0.5Micro Tesla. When higher measurement accuracy is required, the actual measured object should be used for calibration.

3）The influence of surface coating on the measurement results of the tested object

The sensitivity of sensors will vary with different coating materials. If the coating is uniform and the thickness is greater than the depth of eddy current penetration (calculated according to the section on the influence of the measured body size mentioned above). Re calibrate the sensor according to the coating material, which will not affect its use.

4）The Influence of High Frequency Coaxial Cable

High frequency coaxial cables are also a major factor affecting the electrical performance of eddy current sensors.

Due to the sensor operating at high frequencies (oscillation frequency of approximately)1MHzTherefore, the frequency attenuation, temperature characteristics, impedance, length, and other factors of high-frequency coaxial cables have become factors that affect the performance of sensors! For this reason, traditional eddy current displacement sensors are high-frequency coaxial sensors

5）Cables cannot be interchanged

Our company has adopted optimized design of the preamplifier circuit and probe, solving the problem of interchangeability between the probe and the preamplifier. That is to say, using our products, the probe and preamplifier of sensor systems with the same coaxial cable length can be freely interchanged, and the interchangeability error is less than1%.

6）The influence of external magnetic field

The main principle of eddy current sensors is the eddy current effect, so the influence of external magnetic fields should be fully considered in engineering applications!

For external static magnetic fields, due to the constant strength of the static magnetic field, the direction and eddy current magnetic field may exhibit various conditions. Once the direction of the external static magnetic field is determined, its interference with the eddy current magnetic field is also certain. So in practical engineering applications, the influence of static magnetic fields can be measured through on-site experiments to determine changes in sensor sensitivity, which can be eliminated through subsequent circuits or software algorithms.

For external alternating magnetic fields, such as large excitation machines, frequently started large motors, starters, etc., the direction and intensity of the magnetic field may not be a definite value, so the impact of the generated alternating magnetic field on the eddy current magnetic field is also alternating! Therefore, in engineering applications, eddy current sensors should be kept as far away from the range of alternating magnetic fields as possible, or magnetic field shielding measures should be taken to minimize the impact.