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YOKOGAWA LAI143-H53
Product Category: Analog Input Module for Programmable Logic Controllers
Product Overview:
The LAI143-H53 is a 16-channel analog input module designed for the Yokogawa FA-M3 series PLC systems. It accepts 16 channels of 4–20 mA DC current input signals and converts them to digital values for processing by the PLC CPU. The H53 suffix specifies the 16-channel, 4–20 mA input configuration with 12-bit resolution.
Detailed content
Technical Specifications:
| Parameter | Value |
|---|---|
| Number of Channels | 16 channels |
| Input Signal Type | 4–20 mA DC (2-wire) |
| Input Resolution | 12-bit (4096 steps) |
| Conversion Time | 1 ms per channel (scan) |
| Input Impedance | 250 Ω (max) |
| Common Mode Rejection Ratio (CMRR) | ≥ 80 dB |
| Isolation Voltage | 500 V AC (channel-to-channel, channel-to-backplane) |
| Accuracy | ±0.1% of full scale (±0.032 mA) |
| Operating Temperature | 0°C to +55°C |
| Power Supply | 5 V DC (from PLC backplane) |
| Power Consumption | ≤ 1.5 W (typ.) |
| Housing Material | Flame-retardant ABS resin |
| Mounting | DIN rail / PLC backplane insertion |
| Compliance | CE, UL/cUL, C-Tick |
Functional Features:
- 16 independent 4–20 mA input channels with simultaneous sampling capability
- 12-bit A/D conversion provides high-resolution signal digitization
- Channel-to-channel galvanic isolation (500 V AC) prevents ground loop interference
- Built-in common-mode noise rejection (≥80 dB CMRR) for industrial environments
- LED status indicators per channel for diagnostic monitoring
- Hot-swap capable — can be inserted/removed without PLC power-down (backplane design dependent)
Working Principle:
Each of the 16 input channels feeds a precision 250 Ω shunt resistor, converting the 4–20 mA current signal to a 1–5 V DC voltage. This voltage is then sampled by a 12-bit successive approximation A/D converter. The digital value is transferred to the PLC CPU via the backplane bus during each scan cycle. Isolation is achieved through opto-couplers or magnetic isolators between each channel and the backplane.
Key Advantages:
- High channel density — 16 channels in a single module reduces system cost and wiring
- Excellent noise immunity — 80 dB CMRR and 500 V isolation eliminate ground loop issues
- Fast conversion — 1 ms per channel enables real-time process monitoring
- Standardized FA-M3 compatibility — seamless integration with Yokogawa FA-M3 PLC family
- Per-channel LED diagnostics simplify troubleshooting
Applicable Industries:
- Chemical Processing Plants
- Water Treatment Facilities
- Food & Beverage Production Lines
- HVAC & Building Automation
- Batch Processing
- Machinery Control (OEM)
Model Series:
- LAI141 — 8-channel, 4–20 mA
- LAI142 — 8-channel, 0–10 V
- LAI143 — 16-channel, 4–20 mA (this model)
- LAI144 — 16-channel, 0–10 V
Installation Requirements:
- Insert into FA-M3 PLC backplane slot with firm mechanical engagement
- Ensure backplane power is stable at 5 V DC ± 5%
- Use shielded twisted-pair cables for 4–20 mA signal wiring
- Ground the cable shield at the PLC end only (single-point grounding)
- Maintain channel spacing in terminal block — do not mix signal types
Usage Precautions:
- Do not apply voltage signals (0–10 V) to 4–20 mA input channels — will damage the shunt resistor circuit
- Maximum input current: 25 mA — overcurrent will damage the input stage
- Do not exceed 500 V between any channel and backplane ground
- Verify input impedance of field transmitter is ≤ 250 Ω for proper signal development
- Keep away from high-frequency noise sources (VFDs, welders) or use NFLR filters in series
