Main > Main Forum
Encoder benchmark question
PL1:
--- Quote from: RandyT on November 24, 2012, 12:52:45 pm ---I agree with Gatt. There are a lot of system variables in the equation which have not been accounted for.
--- End quote ---
The question still is how to remove those variables to compare different encoders and objectively determine
1.) are they unequal, and
2.) to what extent are they unequal.
--- Quote from: Gatt on November 24, 2012, 11:41:39 am ---1. Strip the USB cable and attack a volt meter there, there has to be some kind of rise/fall when the encoder sends input
--- End quote ---
Sorry to burst your bubble, Gatt, but using a volt meter for this application is like using an hourglass to compare 100 meter sprint times between two runners.
A volt meter does not allow accurate (mili- or nanosecond) time measurement or comparing time differences between two events. That's what the oscilloscope, specifically a digital storage model, is good for.
I guess I need to research what format the outgoing data packets will be in. If the outgoing packet for a common keystroke can be translated into a specific series of 1s and 0s, that will translate into a waveform that can be found, verified, and the time difference measured on a storage scope.
--- Quote from: Gatt on November 24, 2012, 11:41:39 am ---2. Write software to monitor the USB port on the board and see when data reaches it, there's software out there that'll let you look at what comes across the USB port.
--- End quote ---
If you know of a USB packet sniffer that does something similar to what the ping command does, a lead would be greatly appreciated.
Scott
Navigation
[0] Message Index
[*] Previous page
Go to full version