USB’s universal appeal

Perhaps the most common computer connector you will find today is the USB port that adorns every type of computer hardware, including printers, keyboards, cell phones, cameras, flash drives, games, and an increasing amount of industrial equipment. USB stands for universal serial bus, and universal it is, with more than 2 billion devices using the connectors and communication protocol.

08/01/2007


Perhaps the most common computer connector you will find today is the USB port that adorns every type of computer hardware, including printers, keyboards, cell phones, cameras, flash drives, games, and an increasing amount of industrial equipment.

USB stands for universal serial bus , and universal it is, with more than 2 billion devices using the connectors and communication protocol. The current version, USB 2.0, from April 2000, specifies how data is sent up and down the cable.

The standard USB cable has four conductors: two carry power (5 V dc, 500 mA max.) and two, as a twisted pair, carry data. The protocol can support a network of up to 127 devices through one port on the host by using USB hubs. USB cables have a maximum length of 5 m and can be extended by using daisy-chained hubs. The host device, a computer typically, communicates with devices connected directly or via the network. The host communicates via one of three protocols within USB 2.0, depending on the nature of the device and its communication needs:

  • Interrupt—Small amounts of data over an extended time period, as does a computer keyboard.

  • Bulk — A large block of data all at once, such as a printer or digital camera download. Data moves in 64-byte chunks and is verified.

  • Isochronous—Communicates streaming data in real time, audio, video, etc., where there is no error correction.


Agilent U2000 Series of power sensors from Agilent Technologies Inc. are said to offer fast and easy setup with plug-and-play USB connectivity. www.agilent.com

When a host finds a device on the network, either after powering up or when the device is inserted hot, it assigns an address and chooses the appropriate communication protocol. All devices do not communicate at the highest speed. Some that transfer less data use 12 or 1.5 Mbps when that is adequate.

In industrial applications, USB is used in the same types of applications as older serial communication platforms, such as RS-232 and RS-485. While USB has largely displaced older serial protocols in the IT world, for industrial applications the progress is mixed.

“We are seeing more USB on devices,” says Ed Nabrotzky, general manager, Woodhead Industrial Communications. “It’s the coming de facto configuration.” He attributes this to USB’s ease of hooking up, auto recognition, and connecting hot. Technicians prefer USB to more cumbersome RS-232 techniques, however the biggest limitation may be the short cable length.

Others aren’t so ready to change. “For process automation systems, we see limited application of USB communication,” says Todd Stauffer, process automation marketing manager, Siemens Energy & Automation Inc. “USB is used primarily for communicating with printers, although Ethernet is a more prevalent choice, particularly for networked architectures. Serial communication using RS-232 is still a mainstay for process automation, but as PC technology continues to advance, it is becoming harder to find PCs with built-in serial ports, particularly those that might be used to perform configuration tasks.” There are PC adapters which can be plugged into a PC’s USB port allowing it to access the controller’s (MPI/DP) configuration ports if required.

Like Ethernet, USB began as an IT product and has been adapted to industrial uses. Hardened connectors and cabling are available from various sources that permit locking. Some manufacturers use the same locking devices that surround Ethernet connectors to protect USB connectors. Locking methods can be proprietary, however, so check for compatibility.



Author Information
Peter Welander is process industries editor. Reach him at PWelander@cfemedia.com .




The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Women in engineering; Engineering Leaders Under 40; PID benefits and drawbacks; Ladder logic; Cloud computing
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Controller programming; Safety networks; Enclosure design; Power quality; Safety integrity levels; Increasing process efficiency
This article collection contains several articles on how advancements in vision system designs, computing power, algorithms, optics, and communications are making machine vision more cost effective than ever before.
Featured articles highlight technologies that enable the Industrial Internet of Things, IIoT-related products and strategies to get data more easily to the user.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Mobility as the means to offshore innovation; Preventing another Deepwater Horizon; ROVs as subsea robots; SCADA and the radio spectrum
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Women in engineering; Engineering Leaders Under 40; PID benefits and drawbacks; Ladder logic; Cloud computing
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Controller programming; Safety networks; Enclosure design; Power quality; Safety integrity levels; Increasing process efficiency
This article collection contains several articles on how advancements in vision system designs, computing power, algorithms, optics, and communications are making machine vision more cost effective than ever before.
Featured articles highlight technologies that enable the Industrial Internet of Things, IIoT-related products and strategies to get data more easily to the user.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Mobility as the means to offshore innovation; Preventing another Deepwater Horizon; ROVs as subsea robots; SCADA and the radio spectrum
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Women in engineering; Engineering Leaders Under 40; PID benefits and drawbacks; Ladder logic; Cloud computing
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Controller programming; Safety networks; Enclosure design; Power quality; Safety integrity levels; Increasing process efficiency
This article collection contains several articles on how advancements in vision system designs, computing power, algorithms, optics, and communications are making machine vision more cost effective than ever before.
Featured articles highlight technologies that enable the Industrial Internet of Things, IIoT-related products and strategies to get data more easily to the user.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Mobility as the means to offshore innovation; Preventing another Deepwater Horizon; ROVs as subsea robots; SCADA and the radio spectrum
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me