Cranes and pendants
On a crane, Wi-Fi rides a runway of moving steel and shares 2.4 GHz with radio remotes that answer to their own standard, so design the runway coverage and the spectrum plan together.
A crane is a machine that drives through its own coverage. The bridge, the trolley and the load are steel, they travel the full length of the runway, and they stand between your access points and everything beyond them.
Most cranes also carry a radio you do not own: the operator’s remote. Wi-Fi has to work beside it, never in its place.
What it carries
A machine on rails, with data to share. OSHA defines an overhead crane as a movable bridge carrying a hoisting mechanism along an overhead fixed runway, and a gantry crane as the same idea with the bridge carried on legs that run on rails. A crane’s drives keep records the plant wants. One crane drive maker’s app reads signal monitors, run trends, and an event history of 400 alarms, 400 faults and 5,000 runs1 over Wi-Fi, from up to 100 feet away, on a network whose name and password you can set. That is one more network on your runway. Put it in the inventory.
Control and video at the big end. At container terminals, automated gantry cranes run on software or under a worker in a remote location, and remotely operated cranes use cameras and sensors to move containers. One cellular vendor’s planning figures for a remote-controlled ship-to-shore crane give up to 20 cameras and about 200 Mbps of video, against under 600 kbps of control data2, with control carried over automation protocols such as PROFINET. The vendor wrote them to sell 5G. Read them as the shape of the load: heavy video up, light control both ways.
Wi-Fi inside a rail. Some crane Wi-Fi never reaches open air. One conductor-rail supplier sells a slotted waveguide for crane travel that runs IEEE 802.11n/ac/ax at 5 to 7 GHz3, carries PROFINET, PROFIsafe and EtherNet/IP beside video and audio, and lists ship-to-shore, rubber-tired gantry and process cranes as uses. Ask the crane builder which medium carries control before you design around it.
Anti-collision may never touch Wi-Fi. Cranes on a shared runway must know where the others are. One radio remote maker sells a laser system for several cranes on the same runway, with warning and stop outputs at preset distances. One radar positioning maker’s system exchanges every crane’s position between the units on its own 24 GHz radio4, and claims no impact on existing Wi-Fi. Where position data does ride your network, treat it as control.
The pendant, gone wireless. OSHA calls a crane run from a pendant on the floor floor-operated, and a crane run by any method other than pendant or rope, from outside the cab or pulpit, remote-operated. NIST lists pendants to control cranes and machine tools among typical factory radio uses. Trade coverage describes crane remotes hopping in the license-free 900 MHz and 2.4 GHz bands5. These are their own systems. Wi-Fi shares the air with them.
What it needs from the network
Coverage over the whole travel. The link has to hold at both ends of the runway, with other cranes parked in the path and a load on the hook.
A loss-of-signal rule that is not yours. OSHA requires that a remote-operated crane stop any motion whose control signal becomes ineffective. The 2005 edition of ASME B30.2 says the same, and adds that losing the remote signal must not demagnetize a lifting magnet. ASME issued the current edition on August 24, 20226, and it still carries a recommended lever layout for radio crane control transmitters. These rules decide what the crane does when its control signal goes. Your network decides how often that happens.
A standard that stops at the remote. IEC 62745 sets requirements for cableless control systems, such as radio or infrared, between operator control stations and the machine’s control system. It does not deal with cableless communication between parts of a machine that are not operator control stations, and it does not specify protocols, frequencies or bandwidth. IEC lists a stability date of 20267, when the text is due to be reconfirmed, revised or withdrawn. The standard behind the remote says nothing about your channel plan. Your Wi-Fi cannot add to the remote’s stop function. It can only make the remote’s link drop more or less often.
A timeout in writing. For anything the crane sends over Wi-Fi, get the timeout from the crane builder. The loss of comms guide lists the questions, and the Timing Budget holds your measured gap against the answer.
How wireless fails it
The crane shadows its neighbor. One industrial Wi-Fi vendor’s blog describes a 100 m hall with two cranes on one runway8. One access point in the middle risked very low or no signal when both cranes sat near one end, with the nearer crane’s steel in the path. NIST notes that when a large object blocks the direct path, the link may be lost. See moving metal.
Steel that reflects as well as blocks. A measurement study of fixed industrial links lists gantry cranes among the moving objects whose reflections can be comparable to or stronger than the line-of-sight path. Those were fixed links. Devices that never move feel the crane too.
A long, narrow cell. A runway is a corridor with a moving steel wall across it. One automation vendor pitches leaky cable for spaces that are long and narrow or obstructed by machines and pillars. Few access points along the runway mean long cells with weak edges. Many mean more roams.
Roams at the same spots, every trip. A crane client roams wherever cells meet along the runway. NIST warns that hand-off between access points can be too slow. Each roam is a gap, and how to measure a roam gap shows how to time one.
Contention with the remotes on 2.4 GHz. Under FCC rules, a 2.4 GHz hopper must use at least 15 channels9, and adapting its hop set around busy channels is permitted, not required. In Europe, the harmonised standard for the band makes the maker declare whether the equipment is adaptive or non-adaptive, and holds a non-adaptive hopper at 10 dBm EIRP or more to a medium utilization of 10%10. One crane maker’s 2014 press release claims its remote checks whether a channel is free and hops to avoid interference, with up to 40 systems working close together11. Those are claims. A hopper landing on your channel shows up as retries. Wi-Fi that fills the band can cost the remote its link, and a remote that loses its link stops the motion it controls. See Bluetooth and frequency-hopping radios.
Weather, for gantry cranes outside. Outdoor runways add long links, wet snow and moving stacks; see outdoor yards and ports.
Design implications
Give the spectrum plan one owner. NIST says licensed frequencies should be strongly considered where safety is an issue, such as lifting with overhead cranes, because exclusive use minimizes the probability of interference. In unlicensed bands, it suggests approval from an internal governance board. List the remotes, the drives’ own networks, any anti-collision radio and the Wi-Fi together. Keep crane Wi-Fi off 2.4 GHz where remotes work. Where it cannot move, ask the remote maker for its hop set and band options.
Run the path along the runway. A radiating cable or a slotted waveguide keeps the crane a short, steady distance from its antenna for the whole travel. NIST files radiating coaxial cable among tailored solutions for unique requirements. See radiating cable.
Point a link down the runway. NIST notes that directional antennas perform better when the direction of transmission is fixed, and a runway fixes it. In the two-crane hall, the vendor aimed directional antennas covering 80 to 90 m from one end, and the first crane relayed to the second over a separately named network on its own channel.
Bridge the crane, not each device. One client bridge, with the controller, drives and cameras behind it, gives you one radio to place and watch. See workgroup and client bridges.
Give control a second path. NIST recommends path redundancy where RF characteristics change. A runway full of moving steel qualifies. See redundant radio paths.
Queue video below control. In the vendor’s port figures, video outweighs control by more than 300 times. Mark it lower.
How to validate
Ride the full runway, moving. Log the crane’s client end to end at production travel speed, with each other crane parked at each end in turn, with and without a load. Record every gap and roam, and time each gap the same way.
Watch the fixed clients too. Log devices near the runway while the bridge passes.
Capture 2.4 GHz with the remotes in use. Record a spectrogram through a working shift.
Hold the worst gap against the shortest timeout. Write the runway tests into your acceptance test plan, and repeat them after any change to the cranes, the remotes or the channel plan.
A runway surveyed with the crane parked is a survey of the roof. Survey it with the crane moving and every remote in use.
About this page
Built from 20 sources: 7 standards bodies and labs, 3 regulators and government sources, 1 research paper or thesis, 8 vendor documents and 1 other source. Researched and drafted with AI assistance. How pages are made
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Cite this page
Plain
Ben Rutter. "Cranes and pendants." OT Wireless, published October 8, 2026. https://otwireless.com/applications/cranes-and-pendants/
APA 7
Rutter, B. (2026, October 8). Cranes and pendants. OT Wireless. https://otwireless.com/applications/cranes-and-pendants/
BibTeX
@misc{rutter2026cranesandpendants,
author = {Rutter, Ben},
title = {{Cranes and pendants}},
year = {2026},
howpublished = {\url{https://otwireless.com/applications/cranes-and-pendants/}},
organization = {OT Wireless},
}