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ICP DAS’s Wireless Monitoring Solution for Overhead Cranes in Bicycle Painting Production Lines

Using ICP DAS‘s M-7000 series I/O modules and RFU series wireless modem, customers can bridge the communication between overhead cranes and PLCs on the ground through the radio frequency (RF) to control overhead cranes in bicycle painting production lines remotely.


The customer is a manufacturer of rail-type overhead cranes. The factory has custom-made overhead cranes for the bicycle painting lines, namely monorail type cranes, which are used for hanging bicycle frames and then painting them by spraying. In order to avoid the formation of heavy metals due to abrasive and debris generated during sandblasting of workpieces, which can pose a health hazard to the operator, as well as to save time in arranging the crane communication line, the customer hopes to use a wireless method for remote control of cranes.

The problem encountered by the original ZigBee equipment

In the past, the customer has used ZigBee wireless equipment in the planning of the production facilities, but found that after starting the overhead crane, there is a delay or interruption in communication, due to which the overhead crane could not stop in the correct position. This is because the ZigBee communication technology uses the most common operating frequency of 2.4GHz, which has caused interference between the overhead crane motors and the ZigBee modules.

This case study illustrates how ICP DAS‘s RFU-433 wireless controlling solution helps customers to control the overhead crane of a bicycle painting production line without signal interruption during the controlling process.

The on-site picture of the overhead crane

ICP DAS’s wireless control solution for overhead cranes

The structure of this solution can be divided into two parts: the upper side of the overhead crane and the ground side. The programmable logic controller (PLC) on the ground side transmits the control signal to the RFU-433 wireless modem through RS-485 (Modbus RTU). Through the 433MHz wireless frequency band of the ISM (Industrial Scientific Medical) band, the signal is transmitted to another RFU-433 wireless modem on the overhead crane. Then, the signal is sent to the M-7055-NPN-G eight-channel isolated DI/DO module to control the operation of the overhead crane. The structure of this solution is as follows:

The M-7055-NPN-G eight-channel isolated DI/DO module can capture signals from up to eight devices. The maximum load current of each digital output channel is 700 mA; at the same time, the module provides configurable power-on and safety value functions. M-7055-NPN-G modules were placed on overhead cranes to control their on/off.

The RFU-433 wireless data converter can convert RS-232/RS-485 to 433MHz ISM frequency band. Within the line of sight (LoS), it provides a transmission distance of up to 1000 meters at a radio signal transmission rate of 9600 bps. In order to overcome the interference that may be encountered in harsh environments, the wireless transmission baud rate of the RFU-433 can be adjusted to a minimum of 650 bps to enhance the anti-noise and anti-jamming capabilities. In addition, users can adjust 16 wireless channels and 8 group IDs to avoid mutual interference between two adjacent RFU-433 networks, thereby distinguishing and controlling them. In this case, the customer uses an RFU-433 wireless modem on the ground to transmit control commands from a PLC to another RFU-433 wireless modem on an overhead crane over the 433MHz ISM frequency band, which then sends the data to the M-7055-NPN-G eight-channel isolated I/O module via RS-485 (Modbus RTU) to control the on/off function of overhead cranes.


  • ICP DAS‘s remote I/O modules support different communication protocols and various I/O signal types, including analog and digital I/O signals such as current, voltage, strain, temperature, and others. They are equipped with dual “Watchdog” functions, which can turn the control system into a safe state in the event of an abnormal situation. In addition, they also have isolation and overvoltage protection to ensure that they operate with higher reliability.

  •  The RFU-433 wireless modem can effectively solve complex wiring problems. In some industrial areas with harsh environments and complex wiring, wireless transmission can be used to reduce the cost of labor and wiring materials, as well as to facilitate troubleshooting.

  • The 433MHz ISM frequency band provided by the RFU-433 wireless modem can effectively avoid signal interference, and features favorable cost, low power consumption, long transmission distance, and good diffraction performance.

  • The RFU-433 wireless modem is easy to set up. Most settings can only be made by turning a knob and a DIP switch; this greatly simplifies system maintenance as well as the replacement of RFU-433 devices if required.

ICP DAS's wireless communication products

There are many types of wireless networks, and each technology has its own uses. ICP DAS offers a variety of products related to wireless applications, which can convert the serial communication and Ethernet of industrial devices to 3G/4G/5G, Wi-Fi, LoRa, NB-IoT, and other wireless transmission methods. They can easily handle communications applications over large areas as well as field challenges where wiring is difficult due to terrain. In addition to RF wireless communication products, ICP DAS‘s products related to ZigBee, LoRa, and NB-IoT wireless communication are also widely used.

ZigBee builds on the physical layer and media access control based on the IEEE 802.15.4 standard carried over a low-powered, short-distance wireless personal area network (WPAN). It is ideal for automatic control and distributed systems for medium to long distances (from 10 to 700 meters). ZigBee devices are easy to use, have strong anti-interference performance, and guarantee favorable cost and high security. ICP DAS has developed ZigBee series products such as signal converters, repeaters and bridges, protocol analyzers, Modbus data concentrators, and I/O modules and sensors, which are often used in industrial control, environmental data acquisition, parking lot positioning, automation buildings, smart home, and other fields. Related application cases include Smart Aquaculture Solution. Due to the long distance between the fish pond and the control center, data is transmitted via ZigBee ZT-2550 and ZT-2551 wireless transmission modules. This solution not only increases the aquaculture industry’s production capacity, but also helps manage production risks and reduces production costs, allowing the aquaculture industry to move towards digitalization and sustainability.

ICP DAS provides ZigBee communication modules with various functions, such as ZT-2055-IOP (Pair Connection) with one-to-one I/O Pair-connection function, and ZT-2055-IOG (Pair connection for the group) with one-to-many I/O Pair-connection function. The MDC-211-ZT is a ZigBee data concentrator, providing multiple communication interfaces, including Ethernet, ZigBee, RS-232, and RS-485, which can easily transmit different data types back to the control center.

LoRa wireless transmission is a spread spectrum modulation method with low power consumption, and its most significant advantage is the ability to transmit signals over long distances. In line-of-sight propagation, the transmission distance can reach 1.5 kilometers. ICP DAS‘s LRA-900 is a Modbus RTU to LoRa wireless data converter, which provides a transmission distance of 1.5 kilometers with a wireless baud rate of 10,000 bps in line-of-sight propagation. In order to overcome the interference that may be encountered in harsh environments, users can adjust the LRA-900 wireless transmission baud rate to a minimum of 250 bps to enhance noise and interference protection capabilities. In addition, LRA-900 has the characteristics of an adjustable wireless channel and group ID, which can effectively avoid mutual interference during data transmission between two adjacent LRA-900s. The LRA-900 wireless data converter has also been successfully used in the application of “Smart Epidemic Prevention in Hospitals with ICP DAS‘s LoRa Wireless Modem for Mobile Robot.”

The NB-IoT (Narrowband Internet of Things) is a wireless IoT protocol using low-power wide area network technology, featuring wide coverage, favorable pricing, and low network bandwidth requirements. It is often used for non-real-time power-saving equipment with a small number of packet transmissions, such as temperature and humidity sensors, smart water meters, and air quality monitoring devices.


The customer uses ICP DAS‘s wireless monitoring solution to monitor overhead cranes in bicycle painting production lines. The transmission is carried out in the 433 MHz wireless frequency band, eliminating the hassle of physical wiring and signal interference in the past. Remote control of production lines protects on-site personnel from heavy metal hazards during the sandblasting process.

In response to the digital transformation era, ICP DAS provides various wireless solutions to meet different application fields’ needs, so that factories with complex wiring can seamlessly adopt digitalization and create a complete industrial IoT system.

Related products:

M-7055-NPN-G 8-ch Isolated DI and 8-ch Isolated DO Module
RFU-433 433 MHz RF Wireless Modem
ZT-2550 RS-232/RS-485 to ZigBee Converter (ZigBee Coordinator)
MDC-211-ZT ZigBee Modbus Data Concentrator
ZT-2055-IOP ZigBee I/O Pair-connection Module (ZigBee Coordinator)
ZT-2055-IOG ZigBee I/O Group (Pair-connection) Module
LRA-900 LoRa Wireless Modem
GRP-540M-NB Ethernet/Serial to NB-IoT Gateway with GPS
RTU-540P-NB NB-IoT Remote Terminal Unit with GPS

ICP DAS View All

ICP DAS was established in 1993 and strongly focuses on innovation and the enhancement of industrial automation technology. ICP DAS continuously endeavors to develop a comprehensive selection of products ranging from remote I/O controllers, distributed I/O modules, I/O data acquisition boards, programmable automation controllers, industrial communication modules, web-related products, motion control systems, SCADA/HMI software to automation solutions for applications critical to energy management, motion automation, smart factories, intelligent buildings, and smart cities. Our ambition is to provide a wide range of high-quality products and versatile applications, together with prompt and efficient services, that can be implemented to assist in the continued success of our clients worldwide.

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