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Three Key Considerations to Build Reliable Wireless Communications for AGVs and AS/RS

The automated material handling equipment market is expected to grow tremendously in the near future*. While this trend is anticipated, it recently accelerated in the spring of 2020 as a result of two significant driving forces. Namely, the expansion of e-commerce businesses and the social distancing measures imposed on shop floors. In recent years, e-commerce warehouses have become hot property because of the rapidly increasing demand from online shopping. With this surge in demand, efficient and reliable AS/RS systems are crucial to keeping warehouse logistics systems up and running.

In addition to expanding e-commerce business, factory owners are also starting to redesign their shop floors in order to align with social distancing guidelines. Automated guided vehicles (AGVs) are now widely deployed to reduce human contact and increase operational efficiency. With AGVs and AS/RS systems now becoming mainstream, machine OEMs and system integrators are looking to build reliable connectivity platforms to achieve seamless operations in warehouses and factories. Since AGVs and AS/RS are constantly on the move, fast and stable wireless connectivity is a fundamental requirement. The biggest challenge is how to build a reliable wireless communications network for these systems.

In this article, we will highlight some of the key factors machine OEMs and system integrators should be aware of when building robust AGVs and AS/RS systems.

Key Considerations

1. Industrial-grade Designs for Optimal Reliability

On the shop floor, there is a lot of unexpected and often unavoidable electrical interference that can interrupt wireless transmissions or even damage wireless communication devices. Take a motorcycle assembly production line for example. There are multiple pieces of production equipment that can produce unintended electrical potential throughout the workshop. Moreover, in a real environment, there are sometimes ground loops that could have a negative impact on wireless devices. Similarly, the conveyors belts used to move products to the next production stop rely on some kind of motor and drive equipment to generate the belt movement. The electromagnets and electrical currents from this equipment can also negatively affect wireless communications. Last but not least, the wireless devices installed on AGVs and AS/RS equipment endure constant vibration when the vehicle is moving, which can also hinder wireless performance.

Diagram 1: RF and power isolation to protect against EMI

Given these conditions, choosing a robust, industrial-grade wireless solution is a top priority. Wireless clients and APs can be reinforced with RF and power isolation to protect the device against electrostatic discharge damage and sudden inrush currents generated by the motor. They also have a wider operating temperature and feature high ingress protection to ensure that your wireless connections remain stable, even in environments with heavy ambient interference. Through these enhancements, industrial-grade devices are designed to last longer as well.

2. Seamless Wireless Connectivity to Ensure Continuous Operations

In many warehouses, AS/RS equipment moves and fetches goods quickly and efficiently. This is possible through wireless roaming. Roaming technology enables wireless clients to constantly search for and switch to the nearest access point with the strongest signal before the wireless connection goes down. As the vehicles are always mobile, it is essential to evaluate the wireless environment to ensure smooth roaming transitions and seamless connectivity.

In addition, Wi-Fi coverage can also have a direct impact on the quality of wireless connections. Wi-Fi coverage determines how quickly the wireless device can identify nearby APs and thus roam more reliably. Opting for wireless devices with MIMO (multiple-input and multiple-output) capability can further multiply the capacity of a radio link to enlarge Wi-Fi coverage. This subsequently improve wireless performance and eliminates the need to install additional APs.

Lastly, system integrators are often concerned with whether the selected wireless solution supports communication between PLCs and wireless APs/clients. Determining your network communication requirements can help better identify the appropriate WLAN settings for the intended deployment environment. Refer to our white paper on PROFINET Over Industrial WLAN Infrastructure for guidelines and industry best practices.

When selecting wireless communication devices, see if the device can be equipped with millisecond-level roaming technology, consider external antennas for more flexible deployment and to achieve broader Wi-Fi coverage, and follow configuration guides from the device provider.

Diagram 2: Sufficient Wi-Fi coverage and roaming technology to ensure seamless wireless connections

3. Built-in Security Features and Management Software to Enhance Network Security

Nowadays, network security is an increasingly prominent topic. People sometimes neglect how easily basic network management can pose cybersecurity risks to the whole network. For instance, if wireless clients can connect to APs without any form of authorization or authentication mechanism, this kind of unwarranted access may cause network breaches and even shut down the AGV and AS/RS systems. It is highly recommended to secure all wireless communication devices after configuration and to deny unauthorized devices access to the wireless network, creating an additional layer of network security.

To help better manage wireless network security, it is a good idea to consider using management software to visualize the network environment and control the security of all node connections.

Diagram 3: Utilize management software that can prevent unauthorized networking nodes from connecting

Moxa’s Solution

Moxa has helped machine OEMs and system integrators worldwide to augment their AGVs and AS/RS systems for optimal reliability and efficiency. Moxa’s AWK Series AP/bridge/client solutions combine a rugged design with high-performance Wi-Fi connectivity to deliver secure and reliable wireless connectivity. With the MXview network management software and AeroMag technology, customers can easily configure, manage, maintain, and troubleshoot their network. Visit our microsite, The Missing Piece for Your AGVs and AS/RS Systems, to learn more.