Control & Automation Equalisation Junction Boxes – Multi-Cell Signal Conditioning for Process Weighing
Equalisation junction boxes are an essential component in any multi-load-cell process weighing system, combining and balancing the individual signals from multiple load cells before passing a single, accurate weight signal to the digital weight transmitter or PLC input. In control and automation applications — where the weight signal drives automated valve control, batching sequences, inventory management, and process alarms — the quality and stability of that signal is critical. A correctly specified and trimmed junction box eliminates the corner load errors and signal imbalances that would otherwise introduce inaccuracy into the control loop, regardless of how well-calibrated the individual load cells are.
Our range covers passive summing junction boxes with manual corner adjustment potentiometers for standard process weighing installations, and active digital junction boxes with electronic corner correction and digital output for high-accuracy or remotely configured systems. Stainless steel and IP-rated enclosures are available for outdoor, washdown, and corrosive process environments, and ATEX-certified models are available for Zone 1, Zone 2, Zone 21, and Zone 22 hazardous area installations — making our range suitable for chemical processing, pharmaceutical manufacturing, fuel storage, and any process environment where flammable gases, vapours, or combustible dusts may be present.
Junction boxes in our range support 4, 6, 8, and multi-cell configurations and are compatible with all standard analogue load cells (mV/V output). Whether you are building a new process weighing system or replacing a faulty junction box in an existing installation, our technical team can advise on the correct model for your load cell count, environment, and accuracy requirements.
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 process weighing systems
- 4, 6, 8, and multi-cell configurations for process vessels and platforms of all sizes
- Stainless steel and IP-rated enclosures for outdoor, washdown, and corrosive process environments
- ATEX-certified models for Zone 1, 2, 21, and 22 hazardous area process installations
- Surge and lightning protection options for outdoor and exposed process installations
- Compatible with all standard analogue load cells (mV/V output)
- Compact, robust construction for long-term reliability in demanding process environments
Common Applications
- Tank and silo weighing systems feeding weight data to PLCs and SCADA platforms
- Automated batching and dosing — multi-cell vessel weighing for ingredient addition control
- Reactor and process vessel weighing in chemical and pharmaceutical manufacturing
- Hopper and bin weighing integrated with production line automation
- Loss-in-weight and gain-in-weight process control systems
- Hazardous area process weighing in ATEX-classified chemical and pharmaceutical plants
All junction boxes are sourced from leading manufacturers and are compatible with our full range of load cells, digital weight transmitters, and process controllers. Contact our technical team for advice on junction box selection, load cell compatibility, and installation guidance for your process weighing system.
Frequently Asked Questions
Why is an equalisation junction box needed in a process weighing system?
In a multi-load-cell process weighing system, each load cell produces a slightly different output signal due to minor variations in sensitivity, even within the same batch of cells. Without equalisation, these differences cause the system to read different weights depending on where the load is distributed across the vessel — a significant source of error in batching and inventory applications. The junction box trims the signal from each load cell channel using potentiometers or digital correction circuitry, so that all cells contribute equally to the combined output. This corner correction is essential for accurate, repeatable weight measurement in any multi-cell system.
What is the difference between a passive and an active digital junction box?
A passive junction box uses manual potentiometers to trim the signal from each load cell channel — simple, reliable, and cost-effective for most process weighing applications. An active digital junction box uses electronic circuitry to perform corner correction digitally, often with remote configuration via software, and may include additional features such as individual cell monitoring, fault detection, and digital output. Active junction boxes are preferred for high-accuracy applications, systems where remote calibration is required, or installations where individual load cell health monitoring is important for process integrity.
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 process installations. Most tank and silo weighing systems use 3 or 4 load cells, while large platform scales and multi-point vessel installations may use 6 or more. Contact our team for guidance on the correct configuration for your vessel geometry and load cell arrangement.
Can junction boxes be used in outdoor or washdown process environments?
Yes. We stock IP65, IP67, and IP68-rated junction boxes in stainless steel and GRP enclosures suitable for outdoor process installations, washdown environments, and corrosive atmospheres. For outdoor installations subject to lightning or electrical surge risk, models with integrated surge protection are available. Confirm the IP rating, enclosure material, and environmental requirements for your installation when enquiring — our team can advise on the appropriate specification.
Are ATEX-certified junction boxes available for hazardous area process installations?
Yes. We supply ATEX-certified equalisation junction boxes approved for Zone 1, Zone 2 (gas and vapour hazards) and Zone 21, Zone 22 (combustible dust hazards). These are required for process weighing installations in chemical plants, pharmaceutical facilities, fuel storage, and grain handling environments. Contact our technical team before specifying equipment to confirm the correct zone classification, equipment category, and gas group for your installation.
