How to Choose a Strain Gauge Load Monitor
Radiolink load monitor on a crane
Load monitoring devices, also called load cell sensors or tension monitors, measure the force exerted by the load on equipment, structural members or other components subjected to the load. Electronic load and tension monitoring devices find application across a broad spectrum of industry. One example is on construction cranes to assure the load – such as I-beams or fresh-mixed concrete – does not exceed the capacity of the crane. Another application is measuring the strain on wires strung between pylons or insuring that structural components on aircraft are balanced and safe to fly.
Load cells such as the Straightpoint Loadlink and Radiolink equipment available from Tovatech can also be used as crane scales and thus are employed for tension monitoring and weighing.
How a Strain Gauge Load Monitor Works
Using the Straightpoint load and tension monitor and a building crane as the application, the device is positioned between two lifting shackles on the crane lifting cable. Typically its location will be just above the hook that attaches to the load (such as I-beams being lifted from ground level). As tension – or strain – is applied during the lifting operation the device monitors the weight.
The Loadlink model shows the weight on an integral digital LED readout. If distances make this impractical there is an optional battery-powered handheld display and controller connected by cable to the load monitor. Operators can program the tension monitor for taring, weighing units, peak holding for both testing and weighing operations, and for offset adjustment.
As its name implies the Radiolink model communicates wirelessly to a remote display and control unit placed, for example, in the cab of the lifting crane.
Construction safety personnel are aware of the crane and lifting cable weight limits. If the weight approaches these limits an alarm will sound. Similarly, it is important to be aware of the safety factor details found in the spec sheets for load and tension monitors. This gives a margin in case the load is much greater than the operator intended. For example, a safety factor of 5:1 means that the load cell can safely handle 5 times the maximum capacity and was tested to ensure that this is the case. Note: This has nothing to do with the capacity of the crane or lifting equipment. The safety factor’s function is to protect your investment in the load and tension monitor.
Three things to Look for in a Strain Gauge Load Monitor
- Lifting capacity. Loadlink models are available in capacities from 5500 pounds to 275 tons; Radiolink models from 2200 pounds to 275 tons
- Accuracy: Both of these models are accurate to within ±0.3% of applied load
- Record-keeping capability
Other important features and benefits:
Loadlink
Unique adjustable audible setpoint alarm alerts you to unsafe overloads
Compact size for minimal headroom loss, portable, versatile
Powered by standard 9 volt batteries that are long lasting–easy to replace
Nema 4X / IP 65 protection means weatherproof for rugged, outdoor applications
Peak hold function facilitates both testing and weighing applications
Overload counter records a history of lifts to monitor unsafe and improper use
Uses standard Crosby fittings, the highest industry standard for quality and safety
Accurate to ± 0.3% of applied load Superior accuracy to avoid unsafe overloads
Industry leader in safety rating tested 3 times at 2 x the safe working load
Remote output for connection to accessories
Radiolink
Unique 6 digit hexadecimal addressing system ensures no interference so the recorded data is correct
Nema 4X / IP 65 protection weatherproof for rugged, outdoor applications
Peak & trough hold function facilitates both testing and weighing applications
Powered by standard AA alkaline batteries that are long lasting – easy to replace
Uses standard Crosby fittings, the highest industry standard for quality and safety
Accurate to ± 0.3% of applied load to avoid unsafe overloads
Industry leader in safety rating – tested 3 times at 2 x the safe working load
License free – low power radio frequency can be used out of the box with no certifications required
Remote output from base station for connection to a PC to download of data for accurate records
Manufactured from traceable materials guarantees safety through manufacturing process accuracy
Contact the scientists at Tovatech for information on load and tension monitoring equipment.
