March 2016

Five Points to Help You Evaluate Your Wireless Devices in AMH Systems

Automated material handling (AMH) systems, which include the AS/RS (automatic storage and retrieval systems) and AGVs (automated guided vehicles), are modern-day “conveyer belts” that play a key role in manufacturing facilities and warehouses around the world. These machines have taken the manufacturing industry by storm and are here to stay. However, behind every successful AMH installation is a powerful wireless solution that provides the synergy between the machines and humans.

Let’s go through the following five challenges and see how your wireless devices measure up with respect to suitability for AS/RS and AGV systems:

Challenge 1: Wireless Roaming Performance

• Is wireless roaming performance affecting your operational efficiency?
• Are the number of APs and clients deployed at your site more than you can handle, resulting in undesirable results?
• Do you have to tolerate system downtime because of seconds-long client handover times?

Poor roaming performance can lead to low productivity and lack of efficiency. The client devices installed on AMH systems should be equipped with the latest wireless technology that can help them roam from one AP to another with very low or nil handover time. In addition, to avoid system downtime, it is absolutely essential to maintain throughput to ensure that tasks already in progress are completed. The current industry benchmark for client-handover time is in the order of milliseconds.

Challenge 2: 802.11n Support and/or Compliance

• Are your wireless devices built on 802.11n wireless standards?
• Is it possible to enable your wireless devices for 802.11n features?

Wireless devices based on or in compliance with the 802.11n wireless standard have the following advantages:

  • Multiple frequency support—2.4 GHz and 5 GHz in comparison with 802.11bg or 802.11a-only technology
  • High bandwidth and data-streaming
  • MIMO antenna support to overcome multipath effects and increase signal coverage and reception.
  • These capabilities are the most sought after when choosing wireless devices for critical industrial applications. MIMO technology that can support multiple transmission streams is a key factor in maximizing wireless network coverage in environments such as warehouses.

    Challenge 3: Electrical Interference Protection

    • Are you facing disruption of wireless connectivity in your AMH system that can be attributed to inrush current?
    • Are the antennas or antenna extensions installed on the vehicles or shuttles prone to electrostatic discharge (ESD) from other objects, or are they affected by airborne electrostatic particles?

    Wireless devices installed in AMH systems can come in contact with ESDs from the environment or inrush current from other equipment sharing the same power source, resulting in disruption of the wireless connections or in extreme cases causing damage to the devices. A typical solution that system integrators use is to install additional power and antenna isolators on the devices. However, this could be a costly affair if you have to install these isolators on hundreds of devices. Devices with built-in power and RF isolators are the most effective solutions in this scenario.

    Challenge 4. Vibration Protection

    • Are your wireless devices that are mounted on vehicles and shuttles protected against extreme vibration resulting from the horizontal, vertical, or lateral movement of the equipment?

    The vehicles and shuttles installed in AMH systems are constantly on the move. Prolonged exposure to extreme vibrations can lead to broken parts, loose components, and eventually, complete failure of devices. The wireless devices mounted on these moving platforms should be provided with mechanisms to deal with continuous vibration. A wireless device that is built in compliance with the IEC 60068-2-6 standard has complete protection against severe onboard vibration.

    Challenge 5: Protection Against Severe Environmental Conditions

    • Are your devices protected against severe environmental conditions?
    • Does the performance of your wireless device degrade with constant exposure to high or low temperatures, or constant exposure to dust and water?

    Since AMH systems often operate in harsh industrial environments, which include cold-storage warehouses with sub-zero temperatures, the wireless devices installed on AMH system equipment must be able to withstand a wide temperature range of -40 to 75°C and be protected against the ingress of dust and water.

    To learn more about these critical points download our whitepaper.

    Moxa's Solutions

    Moxa’s AWK-A series devices provide all the basic building blocks of a reliable, high-performance mobile Wi-Fi network and a solution that is tailor-made for AS/RS and AGV markets. The AWK-A series devices come with the following features to ensure reliable Wi-Fi systems for your mobile applications:

  • Turbo Roaming technology for seamless roaming with millisecond-level handover time
  • 2 x 2 MIMO technology to maximize Wi-Fi availability
  • Power and RF isolation for disturbance-free Wi-Fi connections
  • Adherence to IEC 60068-2-6 standards for protection against severe onboard vibration
  • Wide operating temperature range from -40 to 75°C
  • To learn more about our AS/RS and AGV solution, visit our microsite.

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