Working with Physically Extended i240/i60x USB Controllers
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One can physically extend a USB Device via a 3rd Party USB Extension Hardware System. These extend USB via an Ethernet Cable, CAT 5/6/7 Cable, or Fiber.

We tested the "WeMe USB 2.0 Extender" with an i600 and found it worked fine with no degradation in i600 performance. We tried it with both a 30m and 60m Ethernet cable (it claims to support 100m). This product has an external power supply at the far end which provides power to the USB device, which is important. The WeMe Extender does not transfer ground across the Ethernet cable; subsequently, a jumper wire between the i60x ground and the device under test ground was needed to establish a ground connection.

There are other products on the market that extend USB. Those that use fiber support greater distances, yet at increased cost. Extender 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).

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

We 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 showed both i60x and we were able to digitize normally as though both devices where attached directly to the computer. In the latency test, we digitized 2 waveforms, one from each i60x, and feed the same 100Hz square wave into both i60x. We 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. The sample rate did not change. 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

If your extender is not working consider: try WeMe USB 2.0, connect wire between instruNet Ground and earth Ground, make sure you have power at far end, make sure your extender supports USB 2.0 High Speed (480MBPs).

More Information

• Working with Multiple i2x0/i60x Controllers
• i240 and i4xx Maximum Sample Rates
• i2x0 and i100 Maximum Sample Rates
• Trigger Reference