On 05/10/2020 07:20 PM, Curtis Dutton wrote:
I have been able to get the yaskawa sigma5 motors turning with the bldc
component in qh mode.
The encoders are a sort of hybrid incremental/absolute encoder. Once they
pass the index point a flag and an offset are returned in the encoder data
that allows the exact rotor angle position to be computed.
I'm trying to find the best path forward for facilitating commutation. Any
guidance would be appreciated.
Fanuc has two types of serial encoders. ABS and INC, for
absolute and incremental.
The incremental type only provide correct shaft angle when
battery backup is provided.
If the battery is disconnected or drained, then you have to
manually crank the motor over
one full turn so the encoder can see the index position.
Then, the controller can determine
commutation from the encoder data.
The absolute type have an additional low-res track that
provides a 1024 count per quadrant
data that is aligned to the motor poles, so a drive could
immediately get commutation data
when encoder power is on. Although Fanuc provides a backup
battery for these encoders,
it seems it is not totally necessary.
Perhaps the Yaskawa also have provision for battery backup?
The flag changing when index is sensed
sounds just like what the Fanuc encoders do.
Jon
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