YOKOGAWA NFAI143-H00 Analog Input Module

YOKOGAWA NFAI143-H00 Analog Input Module

Product Overview

YOKOGAWA NFAI143-H00 is a 16 channel isolated analog input module developed by Yokogawa Electric in Japan specifically for the industrial automation field. It belongs to Yokogawa's classic Centum VP/VX series distributed control system (DCS) I/O module family. As the "data acquisition hub" in industrial control systems, the core function of this module is to accurately convert continuous analog signals (such as current and voltage signals) output by on-site sensors and transmitters into digital signals, and then transmit them to the Centum VP/VX controller through the system bus for processing and logic control, providing reliable data support for real-time monitoring and precise regulation of industrial production processes.

The NFAI143-H00 module, with its design advantages of high precision, high reliability, and strong anti-interference ability, has undergone rigorous industrial environment adaptability testing and can operate stably in harsh industrial scenarios such as high temperature, high interference, and high dust. It is widely used in key industrial fields such as chemical, power, metallurgy, and petroleum refining. It should be noted that the module has been officially discontinued, and its replacement model is NFAI143-H50. The replacement model further optimizes communication performance and environmental adaptability while maintaining the compatibility of the original core functions.

Core technical parameters

The technical parameters of NFAI143-H00 module have been accurately calibrated to ensure measurement accuracy and operational stability in industrial scenarios. The specific detailed parameters are as follows:

（1） Input parameters

-Channel configuration: 16 independent analog input channels, with electrical isolation design between channels, isolation voltage ≥ 500V AC, effectively avoiding signal crosstalk between channels;

-Support signal types: compatible with industrial standard analog signals, including 4-20mA, 0-20mA current signals, 0-10V, 2-10V voltage signals, can directly match the signal output formats of mainstream industrial field equipment such as pressure transmitters, temperature transmitters, flow sensors, etc;

-Input impedance: When a current signal is input, the impedance range is 270 Ω (20mA input) to 350 Ω (4mA input); When the voltage signal is input, the impedance should be ≥ 1M Ω to ensure that it will not have a load impact on the on-site transmitter signal;

-Allowable input range: The maximum allowable input current is ≤ 24mA. When it exceeds the range, the module has overcurrent protection function to avoid internal circuit damage.

（2） Accuracy and Resolution

-Resolution: 16 bit high-precision analog-to-digital conversion (ADC), capable of fine sampling of analog signals, with a minimum distinguishable signal increment as low as 1/65536 of full scale, ensuring precise capture of small signal changes;

-Measurement accuracy: ± 0.1% full scale (FS), temperature drift ≤ 0.005%/℃ within the working temperature range of -10 ℃ to 70 ℃, effectively reducing the impact of environmental temperature changes on measurement accuracy;

-Data update cycle: 10ms/channel, can quickly complete the cyclic acquisition and conversion of 16 channel signals, meeting the response requirements of real-time monitoring in industrial production processes.

（3） Power supply and power consumption

-Power supply voltage: Designed with a wide voltage input, supporting 12VDC to 36VDC power supply, with a rated power supply voltage of 24VDC (± 10% fluctuation), suitable for industrial site standard 24VDC power supply systems;

-Power consumption parameters: When powered by 24VDC, the maximum current consumption is ≤ 540mA, and the power consumption is ≤ 15W; when powered by 5VDC auxiliary power, the maximum current consumption is ≤ 230mA. Low power design can reduce the overall energy consumption of the system.

（4） Environmental adaptability parameters

-Working temperature: -10 ℃ to 70 ℃, can adapt to temperature changes in most industrial plants, outdoor control cabinets and other environments;

-Storage temperature: -20 ℃ to 85 ℃, meeting the requirements of low and high temperature environments during storage and transportation;

-Relative humidity: 10% to 90% RH (non condensing), to avoid circuit short circuits or insulation performance degradation caused by humid environments;

-Protection level: IP50, which can effectively prevent dust intrusion and has a certain splash proof ability, suitable for non outdoor scenarios installed in control cabinets.

（5） Physical parameters

-Installation method: Standard DIN rail installation, compatible with 35mm DIN rail, easy and secure installation, convenient for system integration and later maintenance;

-Dimensions: 40mm (width) x 78mm (height) x 110mm (depth), compact size design can save installation space inside the control cabinet;

-Weight: Approximately 150g, lightweight design reduces the load-bearing pressure of the guide rail and facilitates dense installation of multiple modules.

Core product features

（1） Full channel isolation design, excellent anti-interference ability

The module adopts dual electrical isolation technology between channels and between channels and systems, with an isolation voltage of up to 1500V AC (1-minute withstand voltage test), which can effectively suppress electromagnetic interference (EMI), electrostatic interference (ESD), and common mode interference in industrial sites. In strong electromagnetic environments such as chemical and electrical engineering, interference signals generated by frequency converters, high-voltage equipment, etc. can be avoided from affecting the accuracy of analog signal acquisition, ensuring the stability and accuracy of data transmission. At the same time, isolation design can prevent the risk of on-site equipment failure (such as short circuit, overvoltage) from being transmitted to the control system, enhancing the safety of the entire automation system.

（2） High precision data acquisition, stable measurement performance

Equipped with a high-performance 16 bit ADC chip, combined with Yokogawa's patented signal conditioning circuit and linearization algorithm, high-precision measurement of ± 0.1% FS is achieved. The module is equipped with multiple digital filtering modes (such as low-pass filtering and sliding average filtering), and users can flexibly configure filtering parameters according to the on-site signal noise situation, effectively filtering high-frequency interference signals and improving signal stability. In addition, the module has good long-term stability, with an annual drift of ≤ 0.01% FS, reducing maintenance costs caused by frequent calibration.

（3） Modular and flexible configuration, adapting to multiple scenarios

Adopting standardized modular design, not only is installation convenient, but it also supports seamless compatibility with other I/O modules (such as analog output modules and digital input/output modules) of the Centum VP/VX system. It can be flexibly combined into I/O systems of different scales according to industrial control requirements. The module supports remote parameter configuration through Yokogawa PRM (Plant Resource Manager) tool, including input signal type, measurement range, filtering strength, disconnection detection threshold, etc. Parameter adjustment can be completed without disassembling the module on site, greatly improving debugging and maintenance efficiency. At the same time, the module supports the HART communication protocol (corresponding functions need to be enabled) and can achieve bidirectional communication with the HART smart transmitter. It can not only collect measurement data, but also remotely read the transmitter status, diagnose fault information, and configure transmitter parameters.

（4） Improved protection mechanism significantly enhances reliability

Built in multiple safety mechanisms such as overcurrent protection, overvoltage protection, and reverse connection protection: When the input current exceeds 24mA, the overcurrent protection circuit quickly starts and cuts off the input circuit; When the power supply voltage is abnormal (such as overvoltage, reverse connection), the protection circuit can prevent internal chip damage. In addition, the module has a fault self diagnosis function, which can monitor its own working status in real time (such as power failure, ADC failure, communication failure), and upload fault information to the controller, making it easy for operation and maintenance personnel to discover and handle problems in a timely manner. For signal abnormal scenarios, the module supports two fault output modes: HOLD (maintain pre fault output value) or SETV (output preset safety value). Users can independently set them by channel to ensure that the system can maintain a safe operating state in case of a fault.

Function and Working Principle

（1） Core functions

-Analog signal acquisition and conversion: Receive analog signals output by on-site sensors and transmitters, convert them into digital signals through internal ADC chips, and achieve precise conversion from analog to digital;

-Signal preprocessing and filtering: conditioning (such as amplification, level conversion) and digital filtering of the collected raw signal to remove noise interference and optimize signal quality;

-Data transmission and communication: The processed digital signals are transmitted to the Centum VP/VX controller via Yokogawa Vnet/IP or ESB bus, while supporting bidirectional communication with the controller to receive configuration instructions and fault query instructions;

-Fault diagnosis and alarm: Real time monitoring of the module's own status and input signal status. When a fault is detected (such as signal disconnection, overcurrent, power abnormality), an alarm is immediately triggered and a fault code is uploaded;

-HART communication (optional): Communicate with HART smart devices to achieve dual functions of measurement data acquisition, device parameter configuration, and status diagnosis.

（2） Working principle

1. Signal input stage: The analog signal (such as 4-20mA current signal) output by the on-site sensor/transmitter is connected to the corresponding channel terminal of the module through a shielded cable. The channel isolation circuit isolates the input signal from the internal circuit of the module and other channel signals to prevent interference and risk conduction;

2. Signal conditioning stage: The input signal is amplified and level matched by a signal conditioning circuit to adjust the signal to the optimal sampling range of the ADC chip, while also filtering out some low-frequency interference;

3. Analog to digital conversion stage: The conditioned analog signal is sent to a 16 bit ADC chip, which completes signal sampling and digital conversion at a cycle of 10ms/channel, converting the analog signal into the corresponding digital quantity;

4. Data processing and transmission stage: The digital signal is filtered and linearized by the internal microprocessor of the module to eliminate signal noise and nonlinear errors, and then transmitted to the Centum VP/VX controller through the system bus;

5. State monitoring and feedback stage: The microprocessor monitors the power supply status, ADC working status, and channel signal status in real-time. If any abnormalities are detected (such as signal disconnection or overvoltage), a fault code is immediately generated and uploaded to the controller, while executing the preset fault output strategy (HOLD/SETV).

Core precautions

-Power supply specifications: A stable 24VDC power supply must be provided to the simulated on-site power terminals of the power module, and the voltage fluctuation of the power supply must not exceed the range of 12-36VDC, otherwise it may cause abnormal or damaged module operation; It is strictly prohibited to connect AC power to the module power terminal. Before connecting, it is necessary to confirm that the power polarity is correct;

-Requirements for the use of safety barriers: This module does not support the connection of Zener safety barriers. In intrinsic safety application scenarios (such as explosion-proof Zone 2), isolated safety barriers that meet explosion-proof level requirements must be selected, and the safety barriers must be installed in the safety zone. The safety barrier parameters need to be matched with the module and on-site equipment, meeting the matching principles of Uo ≤ Ui, Io ≤ Ii, Po ≤ Pi, Co ≥ Ci+Cc, Lo ≥ Li+Lc, to ensure intrinsic safety performance;

-Shutdown Replacement Explanation: The module has been discontinued. When building a new system or replacing an old module, it is recommended to use the replacement model NFAI143-H50. When replacing, it is necessary to confirm the compatibility between the replacement model and the original system (such as communication protocol, installation size, wiring method) to avoid system integration failures; When repairing old modules, priority should be given to purchasing original spare parts or choosing a professional industrial automation equipment maintenance service provider;

-Maintenance and Calibration: It is recommended to conduct a comprehensive calibration of the module every 12 months to ensure measurement accuracy; During daily maintenance, it is necessary to regularly check whether the module wiring terminals are loose, whether the shielding layer is well grounded, clean the dust inside the control cabinet, and ensure smooth heat dissipation of the module; It is strictly prohibited to use a megohmmeter to directly test the insulation strength between module terminals. If the insulation performance of the system needs to be tested, all wiring must be disconnected first;

-Fault handling specifications: When a module malfunctions, the power supply and signal input should be disconnected first, and then the fault should be investigated to avoid live operation causing the fault to expand; Troubleshooting can be done by reading the fault code using the PRM tool and locating the cause of the fault (such as power failure, channel failure, communication failure) in conjunction with the manual. After completion of the troubleshooting, parameter calibration and communication testing need to be performed again;

-Cable laying requirements: Intrinsic safety side wires and non intrinsic safety side wires should be laid separately in the cable tray and not mixed together; It is strictly prohibited to lay other power lines inside the intrinsically safe wiring conduit. It is recommended to use blue as a label for intrinsically safe wires for easy identification and maintenance.