Fanuc brushless motors with serial encoders

OK, I have continued to work on this, and am now pretty much up to a commercial product.
One quirk is that the encoders do not know where the index pulse is when powered on
(that's what the backup battery is for). So, when they pass the index position for the first time
after power-on, the reported position jumps suddenly to zero. So, I had to detect this and
suppress sending quadrature counts caused by that change in position. I now have that
fixed. I have several rates of quadrature output to accommodate various encoder
counter systems. It outputs industry compatible "Hall" signals for initial commutation.
I may still need to borrow some encoders to make sure this works with all resolutions
of encoders that Fanuc makes.

For the non-absolute encoders (such as (Alpha)I64 as opposed to (Alpha)A64) you
will need a backup battery so that the encoder can provide commutation info at
power-on. If you don't have the backup battery, and at the first power-on, you
will have to hand-crank the encoder one turn to establish the index alignment.
That is kind of annoying, the absolute version of the encoder provides a separate
commutation track immediately at power-on.

Jon

Just wanted to add that this is now a product listed on my web store
<pico-systems.com/osc2.5/catalog/product_...ath=2&products_id=34>

It produces quadrature encoder output plus index, as well as commutation
(Hall) signals. To get commutation outputs immediately at power-on, you
either need a backup battery on the encoder or be using one of the ABS
encoders.

At least for a while, this needs to be treated as a beta product, until it has been
tested with a wider variety of Fanuc encoders. So far, I have tested with
(alpha)I64, (alpha)A64 and serial pulsecoder A and these all work well.
The serial pulsecoder A is a 1 million count/rev encoder, but right now
I have it set up to report only 64K counts/rev. Otherwise it is very hard
for the quadrature to keep up with the count rate.

Jon