On Thu, Dec 16, 2010 at 9:50 PM, Jon Elson <[email protected]> wrote:
> Igor Chudov wrote: > > I was working on adding a spindle encoder to make my Bridgeport Interact > 2 > > mill capable of rigid tapping. > > > > I finally added one today, and it works on a basic level, as in, EMC2 > gets > > the encoder value through Jon's PPMC. > > > > I am concerned with whether the readout from the encoder is accurate, or, > > perhaps, it is missing some pulses due to some mistake of mine. > > > > The idea that I have is to run the spindle for, say a minute, and then > > compare the count of index pulses with the value of spindle position. > They > > should be close within one, I think. > > > > I already get the encoder float value as ppmc.0.encoder.03.position. How > do > > I get index count? > > > > > Unfortunately, there is nothing counting index pulses. > > The encoder does output index pulses. > > > Yes, but the pulses are very short, and the sample rate is your servo > loop rate, so you are > likely to miss them. (Hmmm, actually, there is a LATCH that holds the > index until the > register has been read, so maybe the previous sentence is not true!) > You should be able > to rig a counter in a HAL component to count every time the index is 1. > Because of the edge-triggered latch, > it should always reset after it is read, so it will only show 1 for a > single sample. Run a while, > stop spindle and compare the counter output with the accumulated encoder > position. > > Thanks. Perhaps I will try to use my digital Harbor Freight tachometer and see if it can count revolutions, and compare that to the encoder position read. i ------------------------------------------------------------------------------ Lotusphere 2011 Register now for Lotusphere 2011 and learn how to connect the dots, take your collaborative environment to the next level, and enter the era of Social Business. http://p.sf.net/sfu/lotusphere-d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
