Fast images in industrial applications: USB, FireWire
The rising resolution and sampling rates of modern digital visual display systems are also inevitably accompanied by the rapid increase in the data quantities to be transmitted. Fast bus systems which find application for similar data quantities available in the consumer sector were taken from the industry particularly for this purpose. Here the typical representatives are bus systems such as FireWire (1394a and 1394b), USB (2.0), as well as Gigabit Ethernet or CameraLink.
All these bus systems need special cables, which are offered in the consumer sector by numerous manufacturers at knocked-down prices. Many of these frequently preassembled cables are developed and manufactured only for static laying or minor mechanical stressing.
Costly production losses would be inescapable, if such cables were used in industrial applications with all the known parameters such as chemicals, electro-magnetic and mechanical load, etc.
These are not only "genuine" downtimes such as wire breakage or short circuits of the litz wires, but errors can be noticed gradually through alteration of the capacitive features with a reduction of the possible transmission rates and increased dampening. The use of substandard materials and a deficient mechanical structure in fiber optic cables can lead to murkiness of the fibers and thus also to reduced data rates.
A genuine troubleshooting in bus cables is possible only with very expensive equipment and lots of time. Depending on the position of the damage, the errors may also occur only sporadically during operation and cannot be found once the facility stops.
The good experiences in thousands of applications with classic field bus systems, e.g. Profibus, Interbus, DeviceNet, etc., and the desire of many customers for comparable cables also for the above-mentioned high-speed bus systems led igus® to develop an own cable series, among others, with the following cable types:
The main focus in the development was on mechanically stable cable designs in order to grant the capacitive, inductive and optical features over a high number of cycles. In the mechanical structure of the shields as well, a long service life was aimed at by material selection and special manufacturing processes.
In the industrial environment, it is not only the electrical and mechanical features that play a role, but also the resistance to a great variety of media such as oils, coolants or the like. The seasoned outer jacket material TPE has already proved its durability in many thousands of applications in other igus® cables.
All cables are subject to ample tests in the igus® laboratory; as there is no existing conclusive test procedure, the igus® engineers chose a very pragmatic method.
Several industrial cameras traversed on a fast linear motor at a speed of 2 m/s, an acceleration of 5 m/s2and a travel of 600 mm, while the bus cables moved continuously in the used e-chain® systems.
1
Stranded strain relief elements
2
Gel-filled, armored fiber sheath
3
Gusset-filling, pressure extruded PUR jacket
Test rig:
10 m CFBUS.055 FireWire (1394a)
tested in an e-chain® of the B10.015.125 series with over 6 million movements with a FireWire 1394a camera.
10 m CFBUS.066 (USB 2.0)
tested in an e-chain® of the B10.015.100 series with over 3.5 million movements with a USB 2.0 camera.
10 m CFLG.2HG.MF. 50/125
tested in an e-chain® of the B10.015.075 series with over 3 million movements with a Fire-Wire 1394b camera with optical output.
Despite the long cable lengths, particularly in USB and FireWire, no adverse effects on the picture quality could be determined even according to this stroke rate. This non-scientific, but practice-oriented test distinctly proves the industrial capability of these high-speed bus cables. This test is not complete and is continuing.