The „smart“ junction box for Loadcells
nothing really new happens during the last years in the business of static weighing.
A weighing system is still consisting of one or more loading assemblies, a junction box for signal summing and an electronic unit to display the weight value and transfer the weight information to the PLC system.
Hense Wägetechnik GmbH offers a comprehensive support for the installation of weighing equipment. The Hense service engineers figured out, that a number of typical installation errors are often repeated in the praxis.
false connection of the 4 – 6 wires between the load cells and the junction box
the Load Cells are out of balance
cable break or bad connection at the terminals
In the praxis the service engineers often ask the customer to measure the single load
cell signals with a multimeter (voltage meter). For this reason it is nessecary to disconnect the load cells and measure the exitation voltage and the individual mV signals of each load cell. Under the line this is a very time consuming process…
To make things easier, Hense Wägetechnik has developed a „smart“ solution called “intelligent junction box”.
The intelligent junction box is powered via the load cell amplifier and does not require
a separate supply voltage. For this reason the junction box can be used in place of a standard junction box.
The following parameter are continuosly monitored and display:
Over- and underload of load cell signals (adjustable)
Cable break and contact faults
Exitation voltage to load cells
Load deviation on load cells
The bright OLED graphical display show system errors and fault conditions with the facility to view individual load cell outputs, average load cell outputs and exitation voltage. A „healthy“ volt free relay contact is available for external connections. All fault messages are transmitted via the on board CAN bus interface. The load cell signal can be transferred via conventional 4 or 6 wire connection to the amplifier. Alternative a save 2-wire CAN bus connection is used for a distance up to 200m and more. If more than 4 load cells or one silo should be monitored, the CAN bus allows to establish a 2 – wire network with multiple junction boxes.
To complete the system, Hense Wägetechnik GmbH offer a high precision load cell amplifier, which is able to communicate with the „intelligent“ junction box. The load cell Amplifier „Target 260” receives the CAN bus information and shows the weight and fault information in the bright display. Errors are stored in the memory of the intelligent junction box and the “Target 260” electronic.
This diagnostic function helps to isolate the source of the error within a short time period. The “Target 260” amplifier can be supplied for wall or table, panel or DIN – rail mounting. A stainless steel enclosure is available as an option.
The following output signals are available: 0(4) – 20mA/ 0 – 10V/ 0 – 5V / 3 voltage free relay contacts /USB interface or serial interface RS 232.
Optional interface: Profibus DP and Profinet…