Telemetry derives from the Greek, tele = remote and metron = measure and is now widely used throughout industry as a technique that enables remote measurement and reporting of a wide range of information. In the widest sense of the term, it includes data transferred over hard wired systems but is generally used to refer to wireless methodology using radio or infrared systems.
From its origins in Russia in the early 1930s, the technique has developed vastly over the years, resulting in many highly sophisticated modular systems now available to collect data in a large range of applications. From the motor racing industry, where it has been a key factor for engineers to assess the data in real time and to ensure the cars were in optimum condition for racing, to monitoring threatened wildlife species, telemetry has revolutionised the acquisition of data from remote sources.
Why Wireless DAQ ?
There are many situations where wireless technology has considerable advantages over hard-wired solutions. The examples above are just two scenarios where, without telemetry, the applications would not be feasible. And it’s not just the logistics of the applications that add to the advantages of wireless DAQ. Considerable savings can be made as there are no cable costs or expenses for associated wiring installation that in turn may involve additional building modifications or maintenance issues.
With the development of protocols such as Zigbee, Bluetooth, Wi-Fi and ETSI, systems can be easily set up and engineers can be assured that communication is secure, while performance is not compromised. In the industrial sector, companies, such as LCM Systems who has recently introduced the T24 wireless telemetry system for multiple data acquisition in real time, have built their systems around customised, proprietary communication protocols that guarantee high integrity, error free digital data transmission and these can co-exist with the protocols mentioned above.
When considering wireless systems another thought, once the security issue has been dealt with, is the battery life of the acquisition modules. In remote applications where there is no mains or DC power available, then battery-driven, low power radio units allow data collection over many years with no sustained power, so are considerably more cost-effective than hardwired systems.
Wireless DAQ Systems for Multiple Data Acquisition
Versatility and flexibility are key for multiple data acquisition. Using the T24 as an example, one acquisition module can provide data to multiple output devices and the output devices can accept data from multiple acquisition modules.
In an engineering test laboratory, for example, any strain gauge bridge, voltage or current output sensor can integrate with the T24 acquisition devices to create wireless instrumentation monitoring systems with a direct line of sight range of 120 metres, which can be further extended with the use of antennas and passive repeaters. This means that a wide range of sensors can be wirelessly monitored including load cells, inclinometers, accelerometers, displacement LVDT, pressure, temperature, humidity, pH and shock. Real time results from these multiple inputs can be displayed on either static or hand-held devices.
WDA in the Manufacturing Industry for Lifting Applications and Stock Control
Shackle load cells are used widely in lifting and weighing applications. Safety is of primary importance, as well as reliability and accuracy. In one company, a wireless data acquisition system is being used to aid operations when material is being moved via crane from storage into the production area. The system ensures that the hoists are not being overloaded and transmits data for basic stock control. The T24 system from LCM Systems provided the ideal solution.
In the factory, there are two hoists on the crane, each rated at 25te. These are attached to a shared spreader beam via two TELSHACK-B wireless, telemetry shackle load cells. The spreader beam then has a travelling hoist (rated at 25te) for lifting coils of material into a production area.
In this particular application, the manufacturer wanted to protect each hoist from overloading, provide the operator with a portable display with large digits for visibility, and a printer for basic stock control.
The wireless shackle load cells were wirelessly connected to two T24-RM1 modules. One module was used to provide a voltage free relay output to switch when the load on each individual hoist exceeded 25te. The other module was used to provide a voltage free relay output to switch when the summed load on both hoists exceeded 25te.
A handheld wireless display enabled the operator to view the individual and summed hoist loads. A print button enabled him to print out the current weight on a T24-PR1. A T24-SO was also connected to the T24-HA, and the RS485 output configured to transmit the summed load to a large digit display with 100mm high digits.
Ease of use and installation made the T24 system the perfect choice. WDA not only streamlined operations within the factory environment, but also provided an important safety role by preventing overloading.
Wireless data acquisition has come a long way since its inception and is an invaluable resource for engineers who are looking for high accuracy measurement data from multiple inputs.
Steve Sargeant. LCM Systems Ltd. Unit 15, Newport Business Park, Barry Way, Newport, Isle of Wight. PO30 5GY.
Tel: 01983 249264
UK Press Contact:
Eileen Holmes-Ievers. In Press Public Relations Ltd. St John's Chapel, High Street, Lambourn, Berkshire. RG17 8XL.
Tel. +44 (0)1488 674200