Allen-Bradley 1756-2WS Dual Channel Weigh Scale Module Hardy

Product Overview

The Allen-Bradley 1756-2WS (developed in collaboration with Hardy Process Solutions) is a high-precision, dual-channel weigh scale module designed for direct integration into the flagship ControlLogix PLC platform. This specialized single-slot coprocessor card interfaces directly with strain-gauge load cells, eliminating the need for independent external weight transmitters. Weighing 0.5 kg (1.1 lbs), the module provides high-speed, 16-bit internal resolution weight tracking directly to the controller backplane, making it an ideal solution for fast-acting batching, heavy tank level tracking, and automated filling applications.

Core Technical Advantages

• Integrated Dual-Scale Architecture: Features two completely independent weighing channels capable of driving up to eight 350-ohm load cells (four cells per channel) simultaneously for multi-vessel process management.
• Advanced C2® Electronic Calibration: Supports electronic sensor matching, enabling automated system calibration via software parameters without handling dangerous, heavy physical test weights on the factory floor.
• WAVESAVER® Mechanical Filtering: Embedded hardware algorithms successfully suppress plant-floor floor vibrations, industrial shock waves, and plant piping resonance to deliver rock-steady weight data under tough conditions.

Technical Specifications

Installation & Engineering Guide

• Chassis Placement Protocol: Leveraging hot-swappable architecture, the 0.5 kg hardware frame can be firmly slid into any open slot of a standard ControlLogix chassis. Guide the module along the plastic alignment tracks until the rear circuit contacts lock tightly into the active backplane.
• Field Scale Termination: Wire your load cell bridge cables directly into the dedicated removable terminal housing. To ensure total structural noise cancellation through the Wavesaver filter system, keep low-level millivolt lines away from variable frequency drives (VFDs) and high-current conduits.
• Software Data Configuration: Add the 1756-2WS module directly inside Studio 5000 via its custom Add-On Profile (AOP). From the tag configuration screens, engineers can select selectable digital averaging rates (from 1 to 255 samples) and assign Net, Gross, or Rate-of-Change measurement tracks to local control routines.

Technical FAQs

Q1: Why is the Allen-Bradley 1756-2WS module co-branded with Hardy Instruments?
A1: The module was engineered using Hardy's patented process weighing technology—including WAVESAVER and C2 electronic calibration—and packaged into a native ControlLogix card format to let users track raw scale processes directly inside the PLC environment.

Q2: How does the module handle real-time material flow calculations?
A2: The onboard processor automatically evaluates the weight data change vector over time to generate a direct Rate-of-Change value. This allows the PLC to track instant loss-in-weight or gain-in-weight flow rates without using heavy CPU calculation blocks.

Q3: Does the 0.5 kg module framework require external power injection to drive eight load cells?
A3: No. The card draws under 1 Amp from the 5 VDC ControlLogix backplane slot to internally generate the regulated 5 VDC bridge excitation voltage needed to power up all eight connected field sensors.