Physically Extend instruNet USB — 100 meters from computer

You can now physically extend a USB Device using a 3rd Party USB Extension Hardware System. These extend USB via an Ethernet Cable, CAT 5/6/7 Cable, or Fiber.

GW Instruments performed the following tests:

• using the “WeMe USB 2.0 Extender” with an i600 and found it worked fine with no degradation in i600 performance
• using both a 30m and 60m Ethernet cable (it claims to support 100m)

Most importantly, this product has an external power supply at the far end which provides power to the USB device. Additionally, the WeMe Extender does not transfer ground across the Ethernet cable such that a jumper wire between the i60x ground and the device under test ground was needed to establish a ground connection.

GW Instruments states that whilst there are other products on the market that extend USB using fiber to support greater distances; they come at a higher cost.

Furthermore, xtender products do not necessarily use the Ethernet protocol and are almost always not compatible with Ethernet routers, even though they might use Ethernet wire/cable/connector hardware (i.e. they are not true Ethernet). As such, avoid extenders that do not include an external power supply or do not support USB 2.0 High Speed (480MBPs).

WeMe USB 2.0 Extender Testing

GW Instruments tested two i600 devices where one was attached directly to the computer and one was extended 60m via a WeMe USB 2.0 Extender. instruNet World (recommended Software) showed both i60x so that GW Instruments were able to digitize normally as though both devices where attached directly to the computer. In the latency test, GW Instruments digitized 2 waveforms, one from each i60x, whilst feeding the same 100Hz square wave into both i60x. GW Instruments then looked at the latency between when each waveform made a high to low transition, and saw a 180 μSec delay between the two waveforms at a constant sample rate. The 180 μSec delay is probably due to a variety of factors, including the:

• extender
• computer
• and Windows Operating system

This test involved: 5000 samples/scan, 1 scan, 150ks/sec/channel, digitize 1 channel from each i600, two i600, one i600 attached directly to computer, one i600 extended 60m via “WeMe USB 2.0 Extender”, same 100Hz square wave input into both channels.

Troubleshooting

GW Instruments suggests that if your extender is not working consider trying WeMe USB 2.0 by connecting the wire between instruNet Ground and earth Ground whilst making sure you have power at far end. Finally, check to make sure your extender supports USB 2.0 High Speed (480MBPs).

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For a further discussion contact our Melbourne office by email or phone: +61 3 9874 5777