Overview
The SBW-644 series field-installed temperature transmitter is a two-wire transmitter (that is, a pair of wires is both the power supply line and the signal transmission line). The two-wire display meter has a strong load capacity and a non-linear correction circuit. It can measure the temperature of various media in the range of -200 to 1800 ℃ in the industrial process, and convert the temperature signal into a temperature signal. The linear 4-20mADC current output signal is sent to the display, adjustment and recording instrument, PLC or DCS system for distributed control.
Main technical indicators
1. Basic accuracy: ±0.5﹪(including cold junction temperature compensation)
2, working voltage: 24VDC
3. Load capacity: when the power supply voltage is 24V, the load is 0～250Ω;
4. The influence of ambient temperature: for every 10℃ change, the error is less than ±0.1﹪ of the calibration range
5. Maximum power supply voltage variation range: ±0.05﹪
6. Maximum load change impact: ±0.05﹪
Ambient temperature: -25℃～+70℃
Relative humidity: ﹤85﹪
Environmental vibration frequency: ﹤60Hz Displacement amplitude: ﹤0.14㎜
Notes:
1. Transmission The power supply of the device must be less than 36VDC, and the high-voltage city power must not be connected to the loop.
2. For the loop composed of the transmitter, the total load resistance should be within the working range specified in the instruction manual.
3. For transmitter modules of different specifications, the display screens cannot be interchanged.
4. When the installation environment is poor (poor air flow, high temperature), please use a high-temperature environment integrated temperature transmitter. Use a heat sink to reduce the working environment temperature and improve reliability.
5. Severe impacts such as impacts and knocks are strictly prohibited during transportation, installation, and use of the transmitter.
6. The calibration of temperature transmitter is a work with high technical requirements. For non-professionals and instruments without calibration, please do not adjust the two potentiometers casually, which will cause the accuracy to decrease or even fail to work normally.
7. During calibration, since the two potentiometers affect each other, the zero and full scale must be adjusted repeatedly. The calibration work is not completed until the accuracy requirements can be met.
Analysis of common faults
1. When the output current of the transmitter is about 27.3mA, the thermal resistance is short-circuited.
2. There is no current output, it is a wiring error.
Selection reference
1. What kind of pressure the transmitter should measure
First determine the maximum value of the measured pressure in the system, generally speaking, you need to choose A transmitter with a pressure range that is about 1.5 times larger than the maximum value. This is mainly because in many systems, especially in water pressure measurement and processing, there are peaks and continuous irregular up and down fluctuations. Such instantaneous peaks can destroy the pressure sensor. Continuously high pressure values or slightly exceeding the maximum value of the transmitter's calibration will shorten the life of the sensor, and doing so will also reduce the accuracy. So a buffer can be used to reduce the pressure glitch, but this will reduce the response speed of the sensor. Therefore, the pressure range, accuracy and stability should be fully considered when selecting a transmitter.
2. What kind of pressure medium?
Viscous liquids and mud will block the pressure interface. Will solvents or corrosive substances damage these media in the transmitter? Materials in direct contact. The above factors will determine whether to choose a direct isolation membrane and a material in direct contact with the medium.
3. How much accuracy the transmitter needs?
The accuracy is determined by nonlinearity, hysteresis, non-repeatability, temperature, zero offset scale, and temperature influence. But it is mainly caused by non-linearity, hysteresis, and non-repeatability. The higher the accuracy, the higher the price.
4. The temperature range of the transmitter
Usually a transmitter will calibrate two temperature ranges, one of which is the normal operating temperature, and the other is the temperature compensation range , The normal operating temperature range refers to the temperature range when the transmitter is not damaged under working conditions, and may not reach its application performance indicators when the temperature compensation range is exceeded.
The temperature compensation range is a typical range smaller than the operating temperature range. Working within this range, the transmitter will definitely achieve its due performance indicators. The temperature change affects its output from two aspects, one is the zero drift, and the other is the full-scale output. For example: +/-X%/℃ of full scale, +/-X%/℃ of reading, +/-X% of full scale when out of temperature range, +/-X% of reading when in temperature compensation range Without these parameters, it will lead to uncertainty in use. The change in the output of the transmitter is caused by pressure changes or temperature changes. Temperature effects are the most complicated part of understanding how to use a transmitter.
5. What kind of output signal do I need to get?
MV, V, mA and frequency output digital output, the choice of output depends on a variety of factors, including transmitters and system control The distance between the monitor or monitor, whether there is "noise" or other electronic interference signals, whether an amplifier is needed, the position of the amplifier, etc. For many OEM devices with a short distance between the transmitter and the controller, the mA output transmitter is the most economical and effective solution.
If you need to amplify the output signal, it is best to use a transmitter with built-in amplification. For long-distance transmission or strong electronic interference signals, it is best to use mA-level output or frequency output.
If you are in an environment with high RFI or EMI indicators, in addition to choosing mA or frequency output, you must also consider special protection or filters.
6. What kind of excitation voltage is selected?
The type of output signal determines what kind of excitation voltage is selected. Many transmitters have built-in voltage regulators, so their power supply voltage range is relatively large. Some transmitters are quantitatively configured and require a stable operating voltage. Therefore, the operating voltage determines whether to use a sensor with a regulator. When selecting a transmitter, the operating voltage and system cost should be considered comprehensively.
7. Do you need an interchangeable transmitter?
Determine whether the required transmitter can adapt to multiple use systems. Generally speaking, this is very important, especially for OEM products. Once the product is delivered to the customer, the cost for the customer to calibrate is quite large. If the product has good interchangeability, even changing the transmitter used will not affect the effect of the entire system.
8. The transmitter needs to maintain stability after working overtime.
Most transmitters will have "drift" after overwork, so it is necessary to understand before buying The stability of the transmitter, this kind of advance work can reduce all the troubles that will occur in future use.
9. The package of the transmitter
The package of the transmitter is often easy to overlook its frame, but this will gradually expose its shortcomings in future use. When purchasing a transmitter, you must consider the future working environment of the transmitter, how the humidity will be, how to install the transmitter, and whether there will be strong impact or vibration.
10. What kind of connection is used between the transmitter and other electronic devices?
Is it necessary to use a short-distance connection? If a long-distance connection is used, do I need to use a connector?
Characteristic analysis
Characteristics of analog type
●High precision
●The range and zero point are continuously adjustable outside
●Good stability performance
●Positive migration up to 500%, negative migration up to 600%
●Two-wire system
●Adjustable damping and durability Pressure
●Solid sensor design
●No mechanical moving parts, less maintenance
●Lightweight (2.4kg)
●Full series of unified structure, strong interchangeability
●Miniaturization (166mm total height)
●The diaphragm material that contacts the medium is optional
●Single Anti-overpressure strength
●Low-pressure cast aluminum alloy shell
Characteristics of intelligent type:
●Super measuring performance, used for pressure, differential pressure, liquid Position and flow measurement
●Digital accuracy: +(-)0.05%
●Analog accuracy: +(-)0.75%+(-)0.1%FS
●Full performance: +(-)0.25FS
●Stability: 0.25% for 60 months
●Turndown ratio: 100:1
● Measurement rate: 0.2S
●Miniaturized (2.4kg) all stainless steel flange, easy to install
●Process connection is compatible with other products to achieve the best measurement
●The only sensor in the world that adopts H alloy sheath (patented technology), which achieves excellent cold and thermal stability
●Intelligent transmitter with 16-bit computer
●Standard 4-20mA, with digital signal based on HART protocol, remote control
●Support for upgrading to fieldbus and technology based on field control.
This information is illegally duplicated from 41021653