October, 2016
www.us-tech.com
Industrial USB Connectors: Universal at Last?
By Nicolas Prou, Product Manager, USB Connectors, Würth Elektronik eiSos O
riginally designed for the consumer market, the universal serial bus (USB) rapidly became a standard in the field.
Now, with the launch of USB 3.1, the technology is ready for industrial appli- cations. USB completely replaced many other ports on computers in consumer markets, thereby eliminating a wide variety of different connectors and cables. In industrial applications, USB has become an increasingly popular way to transfer measurement data, connect mobile devices, or to install software updates on machines. Why then is there not widespread use of USB in industrial settings? Besides restrictions in specifica-
tions, USB has had an image problem. USB connectors are considered cheap accessories for undemanding applica- tions, and not considered a robust industrial connector. This is not entirely unjustified; many products have had quality problems and the price pressure on universal connectors has been extremely high. Frequently, the raw materials
used were not well-matched to the demands of the application, which led to problems with solderability, and consequently, to weaknesses in the locking mechanism and overall dura- bility. Not only did the materials play an important role, but also the mechanical design of the connector. Insertion and withdrawal forces could have a negative impact. In the worst cases, the connector de stroyed the socket during insertion and with- drawal.
EMC Problems with USB Because of its symmetrical data
transmission, USB should be quite resistant to interference. In the case of the inductive interference effect (magnetic field), the twisting of the wires compensates for the interfer- ence. Theoretically, as a result of symmetrization of the partial induc- tances, the interference influences compensate each other. Practically, this interference immunity can be compromised, which has led to USB being considered unsuitable for some applications. The reason often lies in the lack
of symmetry of the inputs and out- puts of the USB controller, or simply in the poor quality of the modules. For example, the interface design (receptacle and housing) could be inadequate. Poor ground reduces the shield attenuation of the cable, and the filters may be poorly grounded. The USB cable could be asymmetri- cal, poorly shielded and have an inad- equate ground connection. The cable deteriorates signal quality, radiates signal harmonics and may have insufficient shielding to protect it from external sources of interference. Only those developers in the
industry who anticipated that the controller or the cable used by the end user may not be sufficiently pro- tected from interference and looked into additional EMC protection were able to circumvent this problem. Manufacturers and developers that ignored the EMC issue by leaning too heavily on the theoretical properties of USB connectors found all kinds of
problems during use. Those who considered USB to be unsuitable
should rethink their decisions in light of the addi- tional advantages of USB 3.1. First, doubling the data rate to 10 Gbps is a powerful argument on its own. Significantly increased power, from 9 to 100W, is also extremely attractive for industrial applications. This allows for even more applications: The power supply can also be reversed — i.e. from the client to the host. Also, USB 3.1 does away with the
tedious poking that comes with insert- ing the USB connector the right way
Size and pin comparison of USB 2.0-only and USB 3.1 C-type versions. Continued on page 59
Page 57
Replaces 3 or more wet tantalum capacitors in parallel or series
Superior capacitance retention at -55ºC
Less weight and requires less space
Rugged stainless steel case withstands up to 80g’s
Glass-to-metal seal prevents dry-out for exceptionally long life
Your Mission-critical applications require SlimPack performance
MLSH Slimpack is designed to meet the most demanding military and aerospace applications. It’s the world’s only hermetic aluminum electrolytic capacitor with a glass-to-metal seal. Slimpack delivers extremely high capacitance at ultra-low temperatures. Energize your next idea with MLSH Slimpack.
cde.com/MLSHSlimpack
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100