A&D AD-4401 Multi-Function Weighing Indicator

Overview

The A&D AD-4401 Multi-Function Weighing Indicator is an industrial-grade digital controller engineered for high-precision dynamic and static weighing applications in regulated manufacturing environments. Based on strain gauge load cell signal conditioning and advanced sigma-delta A/D conversion architecture, the AD-4401 delivers stable, low-noise measurement performance under variable mechanical and electromagnetic conditions. Its core function is real-time mass monitoring and closed-loop process control — particularly suited for checkweighing, loss-in-weight (LIW) feeding, gain-in-weight batching, and static verification workflows across food, pharmaceutical, chemical, and component assembly lines. With a native sampling rate of 100 Hz and internal resolution of 1 part in 1,000,000, the unit supports traceable weight determination at sub-milligram sensitivity when paired with compatible 0.3 µV/d load cells. The device operates as a standalone controller or integrates into higher-level SCADA/MES systems via standardized serial and analog I/O.

Key Features

• Compact DIN-rail mountable housing with IP65 front-panel rating — certified for dust-tight and low-pressure water jet resistance per IEC 60529.
• Dual-stage A/D architecture: high-resolution sigma-delta converter (1:1,000,000 internal) coupled with user-selectable display resolution up to 1:16,000 for optimized readability without sacrificing data fidelity.
• Fuzzy logic-based automatic drop compensation and refill correction — dynamically adjusts target offsets based on historical discharge behavior and material flow consistency.
• Eight programmable operational modes: Static Weighing, Checkweighing, Loss-in-Weight Feeding, Gain-in-Weight Batching, Percent Weighing, Counting, Check Counting, and Peak Hold — each configurable via front-panel keys or remote command set.
• Comprehensive self-diagnostic suite: continuous validation of I/O states, analog input integrity, A/D conversion linearity, power supply stability, and optional module presence (e.g., OP-03 RS-422/485 interface).
• Built-in cumulative logging: non-volatile storage of total batch count and gross accumulated weight — retained across power cycles and accessible via serial query or front-panel recall.

Sample Compatibility & Compliance

The AD-4401 interfaces exclusively with analog output load cells compliant with OIML R60 (C3/C4 accuracy classes) and NTEP Certificate No. 12-012X (for legal-for-trade use in North America). It accepts standard ±10 mV/V full-scale signals and supports excitation voltages from 5 V to 15 V DC. All firmware and calibration procedures adhere to ISO/IEC 17025 metrological traceability requirements when executed using A&D-certified calibration weights and documented SOPs. The unit meets EMC Directive 2014/30/EU (EN 61326-1) and Low Voltage Directive 2014/35/EU (EN 61010-1), and its analog and digital outputs are designed for interoperability with PLCs and HMIs certified to UL 508 and IEC 61131-3. While not intrinsically safe, it may be deployed in Zone 2 hazardous locations when installed with appropriate barrier systems.

Software & Data Management

Configuration and calibration are performed locally via the front-panel keypad and high-contrast fluorescent display with dual-line, 16-character alphanumeric readout. Remote setup and real-time monitoring are supported through ASCII command protocol over RS-232 (current-loop or TTL), RS-422/485 (multi-drop topology, up to 10 units on one bus), or BCD parallel interface. Optional analog 4–20 mA output provides scalable process feedback to DCS systems without requiring protocol translation. Firmware updates are delivered via A&D’s proprietary AD-Config utility (Windows-based), which logs all parameter changes with timestamps and user IDs — supporting audit readiness for GLP, GMP, and FDA 21 CFR Part 11 compliance when used with validated system configurations and electronic signature controls. Data export is limited to ASCII-formatted weight streams; no embedded database or cloud connectivity is provided.

Applications

• Pharmaceutical tablet/capsule checkweighing stations meeting USP & EP weight variation requirements.
• Loss-in-weight gravimetric feeders for polymer extrusion and powder coating lines.
• Automated ingredient dispensing in food processing where recipe accuracy must be maintained within ±0.1% of target mass.
• Static verification of filled containers prior to case packing — integrated with reject mechanisms via dry-contact outputs.
• Component counting in electronics assembly using calibrated reference samples and statistical outlier detection.
• Batch reconciliation in chemical blending operations where cumulative weight tracking supports material balance reporting.

FAQ

What load cell types are compatible with the AD-4401?
The AD-4401 supports standard analog load cells with mV/V output (typically 2–3 mV/V or 10 mV/V full scale), requiring excitation voltage between 5 V and 15 V DC and compliance with OIML R60 C3/C4 specifications.
Does the AD-4401 support Ethernet or USB connectivity?
No. Communication is limited to RS-232 (current loop or voltage level), RS-422/485, BCD parallel, and 4–20 mA analog outputs. Ethernet or USB interfaces are not available as standard or optional modules.
Can the AD-4401 store calibration records internally?
It retains calibration coefficients and zero/span settings in non-volatile memory but does not store dated calibration logs, certificates, or operator entries — external documentation is required for ISO/IEC 17025 compliance.
Is the AD-4401 suitable for use in cleanroom environments?
Yes, provided the IP65-rated front panel remains unobstructed and environmental particulate levels remain within ISO Class 8 (100,000) limits; however, the unit itself is not rated for ISO Class 5 or higher cleanrooms due to lack of sealed internal airflow management.
How many devices can be connected on a single RS-422/485 bus?
Up to 10 AD-4401 units may be daisy-chained on one RS-422/485 network using the OP-03-4401 interface option, with termination resistors installed at both ends of the bus.