Using wireless load cells for weighing and force measurement applications has many advantages over cabled load cell connections. Not only because of being wireless but in some cases is more economical than running conduit, digging trenches, or installing wire trays for the load cell cables. Going wireless also opens the options to easily connect various types of sensors in the same network.
This article is going to focus on the T24 series product range. Check out our article wireless weighing for a brewery highlighting other wireless weighing products.
In the following section we’ll detail what products are available to complete a wireless sensor network.
Products for Wireless Load Cell Applications
Wireless Base Station: T24-BSD
Every T24 2.4GHz (not Bluetooth load cells) system requires a base station to setup / calibrate your load cell or sensor wireless network.
Wireless Sensor Transmitters: T24-ACMi
There are options for various sensors such as load cells, temperature, pulse, pressure transducers, and analog signals 0-10VDC or 4-20mA.
The T24-ACMi uses 2 AA batteries, model T24-ACM operates on 2 D-cell batteries or an external 5-18VDC source.
These transmitters have a wireless range of up to 800 meters (line of sight) under ideal conditions.
Wireless Receivers & Output Devices
Receiving the sensor’s data and outputting a usable signal is what the various output modules are used for.
The T24-AO1i outputs 0-10VDC or 4-20mA, useful for communicating with an analog input to a PLC.
The T24-GW1 is a Modbus gateway for the T24 transmitters, receiving data from various load cell transmitters and transmit a RS485 Modbus RTU to a PLC.
The T24-SO is a serial output module used to send data to a printer, or a scoreboard.
Free Wireless Software for use with T24 2.4GHz Products
T24 Toolkit Software
Used to set up and calibrate the load cell transmitters, built in spectrum analyzer to perform radio traffic site audits.
Load cell logging software, view up to 100 sensors and log the data to a .csv file for further manipulation.
Center of Gravity Software
Module built in to the T24-LOG100 software allows calculating and monitoring in real-time the X&Y axis CoG center of gravity of an object.
Bluetooth Load Cell Transmitter: B24
The B24 connects a strain gage load cell wirelessly via Bluetooth to your smart phone or tablet. Bluetooth compared to the T24 products is less expensive but also has a much shorter transmission distance. The B24 has both IOS and Android apps for viewing the data from the force sensor.
Choose the Correct Technology – 2.4GHz vs Bluetooth
Firstly you have to choose if Bluetooth or a 2.4GHz system is correct for the application. This is simple, if you need more than about 20 meters range choose the T24 2.4GHz products (up to 800 meters line of sight range). Another factor to consider is what do you want to do with the load cell or other sensor’s data. The B24 Bluetooth transmitter is simple to use using a smart phone or tablet to view the data. If you want to do more than just view the readings T24 products are the answer.
If you picked the B24 Bluetooth load cell transmitter, the B24 and a load cell are all you need to have a complete system.
If the T24 2.4GHz products is your solution keep reading, in the next section we’ll dive deeper in to the T24 product range.
Choose the Correct T24 Transmitter
There are two main transmitters for various signal inputs offered in the T24 line. The T24-ACM (operates on 2 D-cell batteries or external 5-18VDC source), and the T24-ACMi (powered by 2 AA batteries). With the D-cell battery option you can get approximately 1 year battery life (1 reading per second) or the AA battery version has about 5 months battery life (1 reading per second).
Other than the power requirements both transmitters settings are identical. You can sample the data at a quicker rate than 1 hertz but it does shorten the battery life.
Using the associated receivers or handheld displays you can put the transmitters in sleep mode, this will greatly increase the battery life when the load cell readings are not needed.
There are multiple antenna options for either transmitter, the standard is an internal antenna. We find this antenna sufficient for most applications achieving a range of up to 500-800 meters clear line of sight to the receiving device in most cases.
Choosing the Correct T24 Receivers & Output Devices
To complete a network for wireless load cells you need to have the appropriate T24 receiving devices.
Using only a base station like the T24-BSD is the least expensive method of viewing and data logging the data from a load cell or other type of sensor using the various free software available.
The wireless handheld T24-HS load cell display works well with applications only needing a portable visual display of the weight. Such as crane scales, tension link, and shackle load cells fitted with the T24 2.4GHz wireless transmitters. Or a simple project as weighing items for shipping weights, like a shipping container or large piece of equipment using compression load cells under the support points of the object being weighed.
Options for receivers like the T24-GW1 Modbus gateway, and the T24-AOi analog output devices are mainly used when communicating with a PLC / HMI system. These models are convenient to interface with PLCs using industry standard outputs like RS485 Modbus, or 0-10V and 4-20mA signals.
Also available is the T24-PR1 wireless printer, T24-LD1 wireless scoreboard large digit display, T24-RM1 relays output module.
The SS-GT24-A Ethernet to cloud device used to capture data from the T24 wireless transmitters and transmit to the cloud for viewing and storing load cell and other types of sensor data remotely via a computer connected to the web.
Wireless Load Cell Project Examples
The Load Cell Systems wireless Safe Crane System shown uses two load pin load cells connected to T24-ACM load cell transmitters. The signal is received by the T24-GW1 Modbus gateway that outputs the RS485 Modbus RTU data to a PLC. The PLC is connected to an industrial HMI that displays the real-time weight on each crane hook. We used built in spectrum analyzer from the T24-BSD base station to choose the least used radio channel available in a high-traffic radio communication environment.
This system is also for an overhead crane. The load cell fits underneath the nut that holds the crane hook in place. The load cell is connected to a T24-ACM-SA wireless load cell transmitter. There is a T24-SO serial output device sending RS232 ASCII data to the large LED scoreboard. There is T24-RM1 relay that collects the load data from the crane hook load cell and has 2 setpoints used for overload and slack detection on the crane. Also shown is a T24 base station used to setup and calibrate the wireless system.
Wireless Load Cell Systems Conclusion
Cutting the load cell cable is not always a bad thing. For many applications it is not possible or feasible to run sensor cables to their receivers. Going wireless is the solution for these projects. With the various sensor inputs available for the transmitters and wide range of receivers making a sensor or load cell wireless network is easy.
As always we recommend contacting a specialist at Load Cell Systems to discuss your unique requirements. You can contact us here, or call 607-426-1467 to talk to an expert.