HITACHI LYA220A Analog Input Module

The HITACHI LYA220A is a versatile analog input module that expands the measurement capabilities of Hitachi programmable logic controllers. It features 8 differential input channels that can be individually configured to accept standard industrial analog signals including 4–20 mA current, 0–10 VDC voltage, and thermocouple (J, K, T) types. With 12-bit resolution and built-in cold-junction compensation for thermocouples, the module delivers high-accuracy conversion of field sensor signals into digital values for monitoring and control.

Key Features

• 8 Differential Input Channels: Offers high density and noise rejection, ideal for multi-point monitoring.

• Configurable Input Types: Software-selectable per channel: 4–20 mA, 0–10 V, or thermocouple (J, K, T, E).

• 12-Bit Resolution: Provides 4096 steps of resolution, ensuring fine measurement granularity.

• High Accuracy: ±0.3% of full scale for current/voltage; ±0.5% for thermocouples (excluding sensor error).

• Optical Isolation: 500 VAC isolation between inputs and logic, preventing ground loops and protecting the PLC.

• Digital Filtering: Programmable averaging filter to smooth noisy signals and improve stability.

Technical Specifications

• Number of Channels: 8 differential inputs

• Input Ranges: 4–20 mA (with 250 Ω internal resistor), 0–10 VDC, thermocouple J/K/T/E (range dependent on type)

• Resolution: 12 bits

• Accuracy: ±0.3% FS (current/voltage), ±0.5% FS (thermocouple) at 25°C

• Conversion Speed: 2 ms per channel (typical)

• Input Impedance: 250 Ω (current), ≥ 100 kΩ (voltage), high for thermocouple

• Cold-Junction Compensation: Built-in for thermocouple inputs

• Isolation: 500 VAC channel-to-logic, non-isolated between channels

• Operating Temperature: 0°C to +55°C

• Certifications: CE, UL

Applications

The LYA220A is ideal for process industries such as chemical, pharmaceutical, food and beverage, and water treatment. It connects directly to 4–20 mA pressure transmitters, 0–10 V level sensors, and thermocouples for temperature monitoring. The module provides the critical data needed for PID control loops, data logging, and operator displays within Hitachi PLC systems.

Integration and Configuration

Installation is straightforward: the module plugs into any I/O slot of a Hitachi PLC rack. Using Hitachi's Pro-H or EC Runner software, engineers assign each channel's input type, scaling (engineering units), and filter settings. The module automatically linearizes thermocouple curves and provides cold-junction compensation. Scaled values are available in the PLC's input image table for use in logic or HMI visualization.

Reliability and Environmental Compliance

The LYA220A is constructed with industrial-grade components and tested for immunity to electrical noise, ESD, and vibration per IEC standards. It operates reliably in ambient temperatures up to 55°C and is suitable for installation in control panels without forced cooling. CE and UL certifications ensure compliance with global safety and EMC regulations.

The HITACHI LYA220A analog input module provides a flexible and accurate interface between field sensors and the control system, enabling precise process monitoring and optimization.