New Application Note: Reducing RF Interference

[CoAMarcus]

Some people have emailed me asking for a means to reduce RF interference on their G203Vs. I typed up an application note that some of you may be interested in if you are running a noise-sensitive application. This is only useful for those who would require a reduction in RF noise and will not improve the performance of the G203V in any other areas.

The file is attached here, and a direct link is below.

http://geckodrive.com/upload/Reducin...terference.pdf

Marcus Freimanis

[BobWarfield]

Marcus, any thoughts on noise relating to the servo side of the world would also be helpful. Encoders seem particularly sensitive. Mariss is having a rant about the HEDS encoders as we speak.

Cheers,

BW

[Mariss Freimanis]

My 'rant' is the recent HEDS optical heads are a circuit component, not a system device. A circuit component must be on a pcb containing other components (line-driver ICs and supply bypass capacitors) to make it a system component capable of reliably driving an encoder cable.

Just last week another customer returned 7 G320 drives as defective. All 7 tested out just fine. The customer's paperwork mentioned HEDS encoders are being used. We suggested he try USdigital's EM1 optical head encoders. He did and all his problems went away. Current HEDS optical heads shouldn't ever be used to drive a cable directly.

Mariss

[Musick7]

Not sure but just maybe,
I might be wrong about this, if RF doesn't stand for "Radio Frequency." OK drivers sometimes get RF interference, Correct? You have written a nice PDF about how to block RF from screwing things up. But my thought is, I watch a Mythbuster episode and I forget all the details about it and what they where testing exactly at the time but, I do remember what they had to do to Make sure 100% of RF interference would not cause the test useless. They built a cage/box of brass screen and then stepped in and took there cell phone inside and showed the TV audience, with the cage door open it would work with less signal. They shut the Door to the brass cage and Zero Signal & Searching for signal.
What I am saying is why can't you put your drivers in a some kind of snug fit case around the drivers. Or like some do they put all there drivers in a PC like case and power supply all in the same Box/Case and just Line the inner case with this Brass Screen material and all your cables that go to your Stepper Motors put all of them in a small PVC pipe and rap the pipe with the screen mesh.
Or if you have your drivers mounted with your motors build a smaller case wherever you have them mounted.

And there is always the final option, build a Box around your inter Machine. That might be a bit expensive... But you will never get RF interference! It could be cheaper than buying shielded cables.. You also will have shielded everything not just your cables, right down to your PC an Power supply with Drivers.
Maybe I am wrong but will this work?

[CoAMarcus]

You are talking about a Faraday cage and that is exactly what a control box is. The control wires leave the box though and must be shielded. This application note is meant for those without their drives in a control box.

Marcus