Dave Wilson, Motion Products Evangelist, Texas Instruments
When I was a young engineer, I was involved in a pretty ugly incident with a three-phase power inverter. No, I didn't get hurt, but the incident shook me up a little. I had designed a three-phase matrix converter, and I had just got it working to the point where I could spin a motor. The U.S. Navy came in for a demo, and I wore my best three-piece suit for the occasion. The demonstration went well, and the Navy seemed impressed with the design. After they left, I was feeling rather cocky from the success of the demo, so I started pushing the limits on the converter. Suddenly, the converter started making a strange noise, but before I could do anything about it, the converter blew up in my face! The T03 transistor packages exploded, showering me with molten metal! It was a miracle that none of the red-hot globules landed on my skin, but my three-piece suit was ruined. I learned a lot of good lessons that day, like to double-check my fuse calculations, and to try and put a little distance between me and any high power equipment I am debugging!
As I recount this story to other motor control engineers, many can relate to what I went through that day, and several can recall even more harrowing memories from their own past. Debugging high voltage power equipment can not only be challenging; it can be DANGEROUS! The problem is exacerbated when you consider that the processor in many variable speed drives is grounded to the negative rail of your DC bus, which is electrically hot with respect to earth ground. This presents a problem when you need to talk to the processor with your earth grounded development tools. The most popular solution today is to employ galvanic isolation using optically isolated USB interfaces to pass the JTAG signals to and from the processor. But many of these isolators are not designed to reject the high frequency noise created by the large dv/dt's from the PWM outputs. Indeed, as a Field Applications Engineer, I was involved in several support issues where the debugger worked fine until the PWMs turned on, and then the drive would lock up! Sometimes it was just a matter of positioning the cables a certain way with respect to the inverter. But even then, you are still physically tethered in close proximity to the drive. Wouldn't it be great to sever this physical connection altogether? I have spoken to several industrial control engineers over the past few years who all said this would significantly improve how they debug their high voltage products!
Enter BlackhawkTM, a division of EWA Technologies Inc, and an elite member of the TI Developer Network. Just in time for Christmas, Blackhawk has unveiled its new USB510W wireless debugger, which modulates JTAG signals over USB 2.0 using the ubiquitous 802.11 b/g/n wireless interface. Now you can debug your drive without the tangled mess of cables, and even be in a different room if you want. Imagine sitting at your desk in your office while you debug the drive in your lab! Or controlling and monitoring your drive on the other side of an explosion-proof wall. Or debugging multiple drives, all communicating over the same wireless network. The possibilities are endless! In fact, drives are not the only products affected. ANY product using a processor which is not earth grounded would stand to benefit from this nifty tool.
For more detailed information on the USB510W wireless debugger, please review the Blackhawk press release,
http://www.blackhawk-dsp.com/downloads/docs/pressrel/Bh510W-PR-Final.pdf
or visit Blackhawk's website:
In the meantime, double-check your fuse sizes, don't wear a three-piece suit when debugging power equipment, and consider going WIRELESS for your next debug session!
