[joeavaerage]

Hi,

It's just the same as any modern top quality servo drive can do the duel encoder feed back but it is not widely used because of the added cost

I paid $450USD (excluding shipping) for 750W B2 series serovs, drives and cables, that is with a 160,000 count per rev encoder.
I did not know at that time about the dual encoder reading feature of the A2 series (1,280,000 count per rev encoder), and had I done so I would
have bought them instead as they are only $500USD (excluding shipping) for 750W servo, drive and cables.

So the dual reading feature can be had for only really a small amount extra.

I use an Ethernet SmoothStepper which is a non-feedback step/direction controller and I could not use the traditional scheme that you outline,
namely the linear scale loop is closed by the controller not the drive.

This is an example of my obersvation that 'servos are becoming ever more sophisticated such that CNCmotion controllers are shedding functions
which are now performed by the servo drive'. The ultimate is distributed motion control like EtherCAT, each servo drive becomes its own motion controller
so the PC is the trajectory planner only, it has no need of a motion control.

Craig

[mactec54]

Hi,



I paid $450USD (excluding shipping) for 750W B2 series serovs, drives and cables, that is with a 160,000 count per rev encoder.
I did not know at that time about the dual encoder reading feature of the A2 series (1,280,000 count per rev encoder), and had I done so I would
have bought them instead as they are only $500USD (excluding shipping) for 750W servo, drive and cables.

So the dual reading feature can be had for only really a small amount extra.

I use an Ethernet SmoothStepper which is a non-feedback step/direction controller and I could not use the traditional scheme that you outline,
namely the linear scale loop is closed by the controller not the drive.

This is an example of my obersvation that 'servos are becoming ever more sophisticated such that CNCmotion controllers are shedding functions
which are now performed by the servo drive'. The ultimate is distributed motion control like EtherCAT, each servo drive becomes its own motion controller
so the PC is the trajectory planner only, it has no need of a motion control.

Craig

These features can't be working very well as there are no CNC Manufacturers using it in the drive only, they have duel encoder feed back but are all closing the loop in the control

Yes I have been using EtherCat and fiber optics since 1999 with my CNC Controls

When you close the loop in the control Both Encoders are controlled not just the linear scale

You will find if you buy from delta direct, drive and motor you won't have much change out of around $1200 the Chinese made are cheap but not all are created equal

[joeavaerage]

Hi,
when I bought the B2 series servos they did not have a braked one and yet I wanted one. The Ebay company (fast-to-buy) I bought from
got one in for me, they said from Delta, maybe a warehouse, and within18 hours. I presume therefore that they deal fairly closely with Delta.
While Delta is a Taiwanese company most manufacturing is done in China

In subsequent emails with them, they now always try to tell me about their latest special....., they claim that on the basis of Delta sale volumes in the
previous year that they had been offered a better discount and they want to pass (some) of that on to me, presumably to induce me to buy more of them.

For example I paid $438USD (excluding shipping) for a 400W B2 series servo/drive and cables in August last year. They offered me the exact same
model servo/drive and cables for $387USD just before the COVID thing blew up.

I cannot, to my knowledge, buy direct from Delta, but I suspect the company I deal with is reasonably close to the source and all factory brand new
with Delta warranty cards etc.

I have done a little research and found that Schnieder Electrical offer a plugin module that allows their LUMIEX32 servo drive to become dual
sensing. Allen Bradley KINETIX 5700 drives also offer dual sensing.

I rather suspect that dual sensing and that loop being closed at the drive is more widespread than you imagine.

Craig