While helping team 842 this year, we found that there are issues with using the 360 counts/rev encoders at the speeds we needed. never got around to actually debug what the issue was. They were using about 6/7 feet of wire routed next to motor wires and that may have been an issue. the reading were erratic changing by a a magnitude of 2 when they were graphed.
To resolve this, we removed the plastic disc from the encoder wheel and replaced it with piece of electrical tape on the disk so we had 1 rising and 1 falling edge. We were able to run the control system to achieve the desired RPM using the modified encoders.
Quote:
Originally Posted by Ether
Why not?
If you put the 360 count encoders on the wheel shaft, that's 24000 counts per second at 4000 wheel rpm. The FPGA can handle 40,000 counts/sec
Use only one channel of the encoder and use the Counter class to trigger on rising edge only.
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Welcome to CD, side effects aren't limited too, but may include, addiction to mechanical and electrical assemblies, desire to program in C, drawing objects in Solidworks and subconscious learning! - Jay H 237 [more] 
13-07-2012, 02:15
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