YOKOGAWA ALR121-S00

Description

Product Description: Signal Conditioner YOKOGAWA ALR121-S00

The YOKOGAWA ALR121-S00 is a high-precision, single-channel signal conditioner from Yokogawa’s acclaimed ‘UTAdvanced’ series, designed for advanced loop control and signal interfacing in demanding industrial processes. This unit acts as a critical interface between field sensors/transmitters and the control system, providing isolation, conversion, and conditioning of analog signals to ensure data integrity and system safety. Engineered for reliability, the YOKOGAWA ALR121-S00 is a key component in modernizing control loops and enhancing measurement accuracy. For detailed technical manuals and configuration guides, visit the product page: YOKOGAWA ALR121-S00. Implementing the YOKOGAWA ALR121-S00 into a control loop provides robust noise immunity and electrical isolation, safeguarding sensitive DCS or PLC inputs.

Key Parameters

• Function: Isolating Signal Conditioner / Converter. It typically accepts a standard process input signal (e.g., 4-20 mA from a field transmitter) and provides an isolated, conditioned output (e.g., a replicated 4-20 mA, or a voltage signal) to the control system.
• Isolation: Features high-performance three-port isolation (input, output, power supply). This breaks ground loops, suppresses electromagnetic interference (EMI), and protects downstream control equipment from high-voltage transients originating in the field.
• Input/Output Signals: The specific model ALR121-S00 defines its signal types. The ‘S00’ suffix typically indicates a standard model, often for a 4-20 mA input to 4-20 mA output configuration. Other variants support thermocouple, RTD, voltage, and frequency inputs.
• Accuracy and Stability: Delivers exceptional accuracy (e.g., ±0.05% of span) and long-term stability, which is crucial for precise measurement and control in critical processes like reactor temperature or product composition.
• Power Supply: Operates on a standard DC voltage range (e.g., 20-55 V DC) common in industrial control panels.
• Configuration: Earlier UTAdvanced models like the YOKOGAWA ALR121-S00 may be configured via DIP switches and a precision potentiometer on the front face, allowing for span and zero adjustment without a PC.

Advantages and Features
The core advantage of the YOKOGAWA ALR121-S00 is its ability to deliver pure, reliable signal integrity in electrically noisy industrial environments. Its high-density isolation prevents measurement errors caused by ground potential differences and protects expensive control system cards from damage. The module’s high accuracy and linearity ensure that the true process variable is faithfully represented in the control system. Its rugged, modular design allows for easy installation on a DIN rail and supports high-density mounting in marshalling cabinets. For instrument engineers, the YOKOGAWA ALR121-S00 represents a trusted, maintenance-free solution for critical signal interfacing.

Application Case Studies in Various Fields

• Critical Temperature Control: Isolating and conditioning a 4-20 mA signal from a reactor temperature transmitter in a pharmaceutical or fine chemical plant, ensuring the control system receives an accurate, noise-free signal for a critical batch process.
• Flow Meter Integration: Connecting a pulse/frequency output from a turbine or Coriolis flow meter to a control system’s analog input card via the YOKOGAWA ALR121-S00, which converts the frequency to a stable 4-20 mA signal.
• Legacy System Integration: Modernizing a control loop by interfacing a new smart transmitter (with HART) to an older DCS that only accepts basic analog inputs, using the conditioner for isolation and signal compatibility.
• Noise-Sensitive Measurements: Installing the YOKOGAWA ALR121-S00 in a loop measuring very low-level signals (e.g., from pH or conductivity analyzers) in a water treatment plant to eliminate interference from variable frequency drives (VFDs) and motors.
• Hazardous Area Interfaces: Providing intrinsic safety interfaces (when used with an associated safety barrier) for field instruments located in classified zones.

Comparison with Competing Products
The YOKOGAWA ALR121-S00 competes with signal conditioners from specialized manufacturers like Moore Industries, Phoenix Contact, Weidmüller, and Pepperl+Fuchs. Its main competitive strengths are Yokogawa’s brand reputation for measurement excellence, the product’s proven field reliability, and potentially superior accuracy specifications. Compared to lower-cost, generic isolators, the YOKOGAWA ALR121-S00 offers higher performance, better long-term stability, and more robust construction. For users with a Yokogawa-centric control environment, it ensures a consistent level of quality and simplifies the procurement of spare parts.

Selection Suggestions and Important Precautions

1. Confirm Exact Signal Types: Verify that the YOKOGAWA ALR121-S00 model is configured for your specific input signal (e.g., 4-20 mA, TC type) and required output signal. The ‘S00’ is a base code; always check the full datasheet for the exact ordering code matching your need.
2. Verify Isolation Specifications: For applications with high ground potential differences or severe noise, confirm the isolation voltage rating (e.g., 1500 V AC) of the module is adequate.
3. Plan for Calibration: While highly stable, the YOKOGAWA ALR121-S00 may require initial calibration and periodic verification as part of the plant’s metrology program. Ensure you have the procedure and equipment.
4. Consider Environment and Density: Ensure the ambient temperature of the cabinet is within the operating range. When mounting multiple units densely, consider heat dissipation; leave recommended space between modules.
5. Follow Proper Wiring Practices: Use shielded, twisted-pair cables for both input and output connections. Ground the shield at one end only (typically at the field or system side, not both) to maximize noise rejection. Never use the YOKOGAWA ALR121-S00 to bypass intrinsic safety barriers unless it is specifically certified for such use. Always source from authorized distributors to guarantee authenticity. Document the configured ranges and calibration dates for each unit in the loop folder.

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