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China, Chinese 100% Original Brand New Rosemounte 644 Smart Temperature Transmitter1 Industrial Products Supplier Manufacturer Details, price list catalog:
China Industrial Products Supplier Manufacturer List Catalog
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Kerui (Weifang) Automation Equipment Co., Ltd.
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Product DescriptionProduct DescriptionRosemount 644 Temperature TransmitterThe Rosemount 644 Temperature Transmitter represents a cornerstone of modern industrial process measurement. As a product of Emerson Electric Co., a global leader in automation technology, the 644 embodies decades of field-proven experience, engineering excellence, and a commitment to reliability. This paper provides a comprehensive technical overview of the Rosemount 644, delving into its design philosophy, hardware architecture, advanced features, configuration methodologies, communication protocols, application scenarios, and the tangible benefits it delivers across various industries. Aimed at engineers, technicians, and procurement specialists, this document serves as a detailed reference for understanding why the 644 remains a preferred choice for accurate, reliable, and intelligent temperature measurement.Temperature is arguably the most critical process variable measured in industrial settings. From ensuring product quality in chemical reactors to maintaining safety in furnace operations and optimizing efficiency in power generation, precise temperature control is paramount. While temperature sensors like Resistance Temperature Detectors (RTDs) and thermocouples are the primary sensing elements, their raw signals (resistance change or millivoltage) are weak, susceptible to noise, and non-linear. This is where the temperature transmitter plays an indispensable role.1. Core Technical Principles1.1 Fundamentals of Temperature Measurement and Signal ConversionThe Rosemount 644 operates on the fundamental principle of converting a physical temperature input into an electrical signal that can be processed and transmitted. This process begins with a temperature sensor—such as a resistance temperature detector (RTD), thermocouple (T/C), millivolt (mV) sensor, or ohmic sensor—being placed in the process environment to measure temperatureFor RTDs, the sensor's resistance changes linearly with temperature. The Rosemount 644 excites the RTD with a constant current, measures the resulting voltage drop (which is proportional to resistance), and converts this voltage into a temperature reading using established calibration curves (e.g., Callendar-Van Dusen constants for Pt100 RTDs). For thermocouples, the sensor generates a millivolt signal based on the Seebeck effect, where a voltage is produced between two dissimilar metals joined at two points (the measuring junction and the reference junction). Once the temperature is measured, the transmitter converts this digital temperature reading into a standardized output signal—typically 4-20 mA DC for analog communication, or a digital signal for protocols like HART, Foundation Fieldbus, or PROFIBUS PA.1.2 Advanced Signal Processing TechnologyA key differentiator of the Rosemount 644 is its advanced signal processing capabilities, which ensure accurate and stable measurements even in noisy industrial environments. The transmitter employs a high-resolution analog-to-digital converter (ADC) to convert the sensor's analog signal into a digital format with exceptional precision.One of the most notable signal processing features is the transmitter's ability to perform sensor drift compensation. Over time, temperature sensors may experience drift due to aging, exposure to harsh conditions, or mechanical stress. The Rosemount 644 continuously monitors the sensor's performance and can issue warnings when drift exceeds a predefined threshold, allowing for proactive maintenance before measurement accuracy is compromised. Additionally, the transmitter supports sensor matching, where it is calibrated specifically for a particular sensor to eliminate errors associated with sensor-to-sensor variations.2. Key Features and Functional Advantages2.1 High Measurement Accuracy and StabilityAccuracy is the most critical performance metric for any temperature transmitter, and the Rosemount 644 excels in this regard. Its key accuracy specifications include:Analog Accuracy: ±0.03% of span, ensuring precise analog signal output.Digital Accuracy: For Pt100 RTDs, ±0.15°C (±0.27°F), representing exceptional precision in digital temperature measurement.Ambient Temperature Effect: For Pt100 RTDs, 0.003°C/1.0°C, meaning minimal measurement error due to changes in ambient temperature.Stability: ±0.1% of span per year, ensuring consistent performance over time without frequent recalibration.These accuracy specifications are achieved through a combination of high-quality components, advanced signal processing, and rigorous calibration during manufacturing. The transmitter's stability is particularly valuable in industries where long-term measurement consistency is critical, such as pharmaceuticals and semiconductor manufacturing.2.2 Advanced Diagnostic CapabilitiesThe Rosemount 644 is equipped with a comprehensive suite of diagnostic features that enable proactive maintenance, reduce downtime, and enhance operational safety. These diagnostics can be categorized into three levels:Advanced Diagnostics: Include sensor drift warning, thermocouple aging detection, and minimum/maximum temperature tracking. Sensor drift warning monitors the sensor's performance over time and issues an alert when drift exceeds a user-defined threshold. Thermocouple aging detection identifies degradation in thermocouple performance due to prolonged exposure to high temperatures or corrosive environments.Predictive Diagnostics: The Hot Backup? feature, available with dual-sensor configurations, continuously monitors the performance of both primary and secondary sensors. If the primary sensor fails or drifts beyond acceptable limits, the transmitter automatically switches to the secondary sensor, ensuring uninterrupted temperature measurement. This predictive capability is critical in applications where process interruption could result in significant financial losses or safety hazards.SpecificationOperating Temperature Range-40°C to 85°C (-40°F to 185°F)Storage Temperature Range-50°C to 100°C (-58°F to 212°F)Humidity Range0-100% relative humidity, non-condensingIP RatingTypically IP66 or IP68, indicating complete protection against dust ingress (IP6X) and protection against water ingress (IPX6: protection against powerful water jets; IPX8: protection against prolonged submersion in water)Vibration ResistanceComplies with IEC 60068-2-6, capable of withstanding vibration frequencies from 10 Hz to 500 Hz with amplitudes up to 0.75 mm.Shock ResistanceComplies with IEC 60068-2-27, capable of withstanding shock impulses up to 50 g for 11 ms.Company ProfileKeRui (Weifang) Automation Equipment Co. Ltd. Has maintained a cooperatve relationship with Rosemount for 15 years, and our purchase quantity has reached 20,000 units.We supplied the tuning fork level gauge to the Rosemount factory and have been well received by the Beijing factory. We have cooperated with Yokowaga and maintained a cooperative relationship for 8 years, and our purchase quality has reached 7000 units.The companies we have cooperated with:1. Awarded "Outstanding Supplier by Yanchang Petroleum in 20082. In December 2012, our company was awarded the "Excellent Equipment Service Award" for the expansion project of units 6 and 7 of the Guangdong Guohua Yuedaishan Power Plant3. Awarded "Outstanding Supplier by Yaxing Group in 20134.200 transmitters for Haihua Group's ethylene debottlenecking transformation project in 2015.5. In 2018, we were rewarded as a National Nuclear Power Instrumentation Industry Measurement and Testing Alliance member.6.160 transmitters and 20 electric autuators for the Shandong Laigang Yongfeng Steel expansion project in 20197.In 2022, Jinneng Chemical (Qingdao) Co., Led/ Jinneng 2x450,000 tons/ year high-performance polypropylene project (newly built) equipped 460 transmitters from our company.8. In 2022, Shandong Qinghe Chemical Technology Co., Ltd.s hydrogen peroxide method epoxy propane device and supporting hydrogen peroxide device expansion project used 253 pressure transmitters.9.In 2022, the Wanhua Chemical HTN project NPG installed 320 transmitters and 50 sets of valve positioners.CertificationsOur ServiceOEM / ODM servicesTo meet the user diversified requirement, Holykell have established a set of customer service and technical support system with OEM / ODM order as the center, and responded and Handle the customer's requirements in a timely manner to ensure accurate delivery time and product quality.Order servicesFastest reply:Professional sales engineers 7/24 online servicesPayment terms:T/T ,Western union, Paypal, Credit Card, L/C othersFast delivery: within 24 hours release the cargo (normal spec.), Customized 7-12 days after payment . MAINTENANCE & AFTER-SALES SERVICESCustomer Feedback: Sales engineers and technical engineers will be one-on-one service for you to exclude all obstacles when use our sensors.Warranty period: 12 monthsProduct life-long maintenance: Holykell can provide you with the maintenance of the whole life of the sensorsPackaging & ShippingFAQQ1: How long will it take you to give me the reply?A: We will reply to you as soon as we see the informationQ2: What is the delivery time?A: Our delivery time is within 3- 7 days after we get your payment; for large qty mass orders, the time should be confirmed again for youQ3: How about your package? A: Do not worry about the package. We have a lot of experience in packing, and all our packages are wooden case packages.Q4: How about the payment terms?A: You can choose T/T.Q5: Do you provide samples? A: Yes, we have materials in stock to help you get the samples as soon as we can.Q6: What is the MOQ?A:1PC.Q7: Can I get a lower price if I order large quantities? A: Yes, cheaper prices with larger orders.Q8: Why choose us?We have a perfect customization, not only to provide you with quality products, but also to have a professional customer service team available at any time to provide you with support. We pay more attention to establishing a long-term cooperative relationship with you to achieve continuous business growth.Q9: How can we guarantee quality?We have strict requirements on the quality of our products, and we will conduct a final inspection of our products when we ship them.
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