Junction Boxes 101

Precision and reliability are paramount in test and measurement. As systems become more intricate, junction boxes become increasingly significant, incorporating various sensors, such as load cells, transducers, and multi-axis sensors, with instrumentation for efficient signal management.

Junction boxes offer a versatile solution for consolidating connections, optimizing signal quality, streamlining setups for measurement testing programs in the lab, and monitoring the performance of components, products, and equipment.

What are Junction Boxes?

Junction boxes are enclosures designed to serve as centralized hubs for controlling connections. In test and measurement, these boxes function as tools between sensors and instrumentation, providing a secure and organized space for electrical systems and components, signal conditioning, and protection against environmental factors.

In its most basic form, a junction box provides a convenient method for connecting multiple load cells to a single indicator. The junction box applications enable individual load cell cables to be wired into the junction box, and then a single cable connects the junction box to the instrumentation.

Junction boxes are intermediaries between the sensor and the display or indicator, making maintenance much more manageable. Consolidating connections simplifies installation and troubleshooting, reducing downtime and maintenance costs.

Junction boxes minimize noise and interference by providing a controlled environment for signal management, leading to more accurate measurements.

Interface Junction Boxes

Junction boxes accommodate various sensors and instrumentation, offering system expansion and modification flexibility. These instrumentation devices are standard in weighing applications where more than one load cell supports a tank, silo, or scale. The individual load cell cables are wired into the junction box, and then a single cable connects the junction box to the instrumentation. Our multi-function weight transmitter junction box has a compact design and signal-conditioning functions.

JB104SS 4-Channel Stainless Steel Junction Box

The model JB104SS junction box connects to and trims up to four load cells per board. It may also be combined with additional junction boxes through the expansion port on the main board to connect multiple junction boxes. This will allow the summing of more than four load cells if needed. The JB104SS is a small 4×6.5×1.75—for installations where space is limited. The standard configuration is for two to four load cells and provides a 20% trim range.

• Stainless steel, NEMA Type 4X enclosure
• Jumpers enable trimming
• Breather vent
• Conformal coated circuit board.
• Number of cells: two, three, or four single cells
• Expansion port

JB1100 4-Channel Advanced Signal Conditioning Transmitter Indicator and Junction Box

The JB1100 instrument is ideal for PLC systems requiring load cell weight data. Interface’s Advanced Signal Conditioning Transmitter Junction Box offers maximum control without the additional cost or space required of a traditional weight indicator. This multi-function weight transmitter junction box has a compact design with signal-conditioning functions. This product can be an independent or dependent four-channel instrument. The JB1100 allows for the direct reading and diagnosis of each individual connected load cell or summed as a whole.

• Four independent scales or four load cell inputs
• Red LED display (13mm) and six LEDs show active functions
• Configurable calibration and setup
• Calibration using linearization points
• Diagnostic information via serial port
• Analog Output Standard Opto isolated, 16-bit 0-20 mA, 4-20 mA, 0-5 VDC, and 0-10 VDC
• 12-24 VDC Power and comes with a 120VAC Power Supply

Four Advantages Using Junction Boxes

#1 Reduction of Clutter: Junction boxes simplify connections of multiple sensors to a single instrument, saving space and improving control.

#2 Signal Conditioning: Many junction boxes incorporate signal amplification, filtering, and linearization, ensuring optimal signal quality before transmission to instrumentation.

#3 Protection: Junction boxes shield sensitive electrical connections from dust, moisture, and contaminants, enhancing system reliability and longevity. This is ideal for use in outdoor settings or exposed environments.

#4 Calibration and Adjustment: Some junction boxes offer sensor calibration and zero adjustment provisions, allowing for fine-tuning in the field.

Junction Box Use Cases

Inventory Management

Using a weight-based inventory management system controls costs and improves operations. Interface suggests installing MBI Overload Protected Miniature Beam Load Cells under each corner of the inventory shelves. A JB104SS 4-Channel Stainless Steel Junction Box connects to each load cell and to a WTS-AM-1E that wirelessly transmits the sum weight to the WTS-BS-1-HA Wireless Handheld Display for multiple transmitters and the WTS-BS-6 Wireless Telemetry Dongle Base Station when connected to the customer’s PC. Results are displayed, logged, and graphed in real-time. Get more information.

Treadmill Force Measurement

When a project requires the ability to measure the ground reaction forces (GRFs), they also want to measure and study the runner’s foot-strike patterns at different speeds. They also want to be able to record and graph the runner’s contact time, aerial time, and lower limb acceleration. Multiple of Interface’s SSB Sealed Beam Load Cells can be installed under a metal platform inside the treadmill. The runner’s foot-strike pattern data are picked up and displayed when the SSBs are connected to the JB104SS 4-Channel Stainless Steel Junction Box.  The total amount of force is shown through the 480 Bidirectional Weight Indicator. Read more.

Weighing Control System for Barrels of Crude Oil

Interface’s solution supports a weighing system used to Interface’s amounts of crude oil, which secures four SSB Sealed Beam Load Cells at the bottom of a metal platform. The load cells will measure the force applied by the weight of the barrels of crude oil. All four SSBs connect to a JB104SS 4-Channel Stainless Steel Junction Box connected to the 480 Bidirectional Weight Indicator. When combined, the accurate weight display assists in easy management. See the application note.

Garbage Bin Measurement System

A garbage disposal company assesses the load capacity of its garbage truck bins using a force measurement system to alert them when bins reach maximum capacity. Interface’s solution is to customize four SSB Sealed Beams under the garbage box body with customer-required capacity installed on either side by the customer with truck manufacturer guidance. This ensures they follow the transportation departments and the manufacturer’s safety requirements. When trash piles up inside the box body, it will push more force down onto the SSB Sealed Beam Load Cells. When maximum load capacity is reached, the results are reviewed and displayed in real-time when connected to the 4850 Battery Powered Bluetooth Weight Indicator. Get more details.

This versatile device combines a junction box with advanced signal conditioning capabilities and a built-in display. It is ideal for applications involving load cells, transducers, and strain gages, offering features like:

• Excitation Voltage: Supplies power to sensors.
• Signal Amplification and Filtering: Optimizes signal quality.
• Linearization: Corrects non-linear sensor output.
• Digital Display: Provides real-time measurement readings.

To find the right solution for your project, use the Interface Guides.

Junction boxes play a vital role in modern test and measurement systems by providing a centralized platform for signal management. Their ability to consolidate connections, condition signals, and protect against environmental factors enhances accuracy, simplifies installations, and improves system reliability. From industrial weighing to multi-axis force measurement support, junction boxes are invaluable in achieving precise and dependable results in various applications.