Tank, Silo & Vessel Equalisation Junction Boxes – Multi-Load-Cell Weighing System Components
Equalisation junction boxes are a critical component in any multi-load-cell weighing system, providing the electrical connection point where signals from multiple load cells are combined, trimmed, and balanced before being passed to the weight indicator or controller. Used in tank weighing, silo weighing, vessel weighing, and large-capacity platform scale installations, they ensure that each load cell contributes equally to the overall weight reading — eliminating errors caused by uneven load distribution, structural asymmetry, or minor differences in load cell sensitivity.
Without proper signal equalisation, a multi-load-cell system will produce inaccurate readings even if each individual load cell is correctly calibrated. Our range of equalisation junction boxes includes passive summing boxes with manual corner adjustment potentiometers, active digital junction boxes with electronic trimming, and stainless steel IP-rated enclosures for harsh industrial environments. ATEX-certified models are available for hazardous area installations in Zone 1, Zone 2, Zone 21, and Zone 22 — making our range suitable for chemical processing, pharmaceutical manufacturing, and any application where flammable gases, vapours, or combustible dusts may be present.
All junction boxes are compatible with standard analogue load cells (mV/V output) and are available in configurations supporting 4, 6, 8, or more load cells. Whether you are building a new tank weighing system from scratch or replacing a faulty junction box in an existing installation, our technical team can advise on the correct specification for your application.
Key Features
- Manual corner adjustment potentiometers for precise load cell signal trimming and system balancing
- Active digital junction boxes with electronic corner correction for high-accuracy multi-cell systems
- Stainless steel and IP-rated enclosures for washdown, outdoor, and harsh industrial environments
- ATEX-certified models for Zone 1, 2, 21, and 22 hazardous area installations
- 4, 6, 8, and multi-cell configurations to suit a wide range of tank and vessel weighing systems
- Compatible with all standard analogue load cells (mV/V output)
- Surge and lightning protection options available for outdoor and exposed installations
- Compact, robust construction for long-term reliability in demanding environments
Common Applications
- Tank weighing systems — liquid storage, chemical dosing, and process vessel weight monitoring
- Silo weighing — bulk solids, grain, powder, and aggregate storage monitoring
- Vessel and reactor weighing in chemical and pharmaceutical manufacturing
- Large-capacity platform and floor scale construction using multiple load cells
- Hopper and bin weighing for batching and process control applications
- Hazardous area tank and silo weighing in ATEX-classified zones
All junction boxes are sourced from leading manufacturers and are compatible with our full range of load cells and weight indicators. Contact our technical team for advice on selecting the correct junction box for your load cell configuration, environment, and accuracy requirements.
Frequently Asked Questions
What is an equalisation junction box and what does it do?
An equalisation junction box (also called a summing box or load cell junction box) is an enclosure that connects the signal cables from multiple load cells in a weighing system. It combines the individual load cell outputs into a single signal for the weight indicator, and includes trimming potentiometers or digital correction circuitry to balance the contribution of each load cell — ensuring the system reads accurately regardless of where the load is applied on the platform, tank, or vessel.
Why do I need a junction box for tank or silo weighing?
Most tank and silo weighing systems use three or four load cells positioned under the vessel. Because no installation is perfectly symmetrical — and because load cells have minor sensitivity variations even within the same batch — the signals from each cell must be balanced before they reach the indicator. Without a junction box to equalise these signals, the system will produce errors that vary depending on where the load sits within the vessel. A properly trimmed junction box eliminates this error and ensures accurate, repeatable weight readings.
How many load cells can a junction box support?
Our range includes junction boxes for 4-cell, 6-cell, and 8-cell configurations, with some models supporting additional cells for large or complex installations. The number of cells required depends on the vessel geometry, capacity, and structural design — most tank and silo systems use 3 or 4 load cells, while large platform scales may use 6 or more. Contact our team for guidance on the correct configuration for your application.
What is corner adjustment and why is it important?
Corner adjustment (also called corner trimming or span adjustment) is the process of fine-tuning the signal from each individual load cell so that the system reads the same weight regardless of where the load is placed. This is done using potentiometers inside the junction box, which allow the sensitivity of each load cell channel to be adjusted independently. Correct corner adjustment is essential for accurate weighing in multi-cell systems and should be carried out during commissioning and after any load cell replacement.
Are ATEX-certified junction boxes available for hazardous areas?
Yes. We stock ATEX-certified equalisation junction boxes approved for use in Zone 1, Zone 2 (gas and vapour hazards) and Zone 21, Zone 22 (combustible dust hazards) classified areas. These are required for tank and silo weighing installations in chemical plants, pharmaceutical facilities, fuel storage, and any environment where flammable atmospheres may be present. Contact our technical team before purchasing to confirm the correct zone classification and equipment category for your installation.
