Dear Erik,
Thanks for your reply.



The quadrature decoder output is 32 bits wide and is read as 4 bytes one after the other. The decoder presents this output on its data bus and latch it on data bus. The micro reads it directly through 8 port pins. The byte to be read [ ie. one among 4 ] is selected by SEL1 and SEL2 signals generated by micro. When OE is pulled low the selected byte is latched on encoder data bus. Micro reads the bytes one by one by first making proper byte selection using SEL1 and SEL2 signals and then making OE low, thus there is no question of very fast or very slow output from quadrature decode.


The decoder output is diffrential I have talked to manufacturer and confirmed that the output is true diffrential there are 8 wires A, /A, B, /B, I, /I +ve supple and gnd. This decoder output which is true diffrential is properly terminated by 120 ohms resisotrs and is fed to AM26LS32 to make it single ended. The single ended output coming out of AM26LS32 is then fed to decoder HCTL2032.



There are no relays or any other source of noise nearby except motor. And if at all there would have been noise problem it wouldnt show effect only while stopping the motor. In my case if i run motor continously then decoder is giving very accurate reading of shaft position. But every time i stop it there is an error produced which is cummulative and goes on increasing every time i stop the motor.



I too thought the same initially and changed motor encoder and control board but still problem exists.

Yes I want to rectify the problem before i install it in real machine.

Thanks & Regards,
Prahlad Purohit