Kanalog with SureServo AC Servo and Linear Scales

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RogerFroud
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Joined: Tue Mar 30, 2021 8:07 am

Kanalog with SureServo AC Servo and Linear Scales

Post by RogerFroud » Sat May 01, 2021 8:12 pm

I can now see how to interface the Linear Scales, but Ideally I'd like to stay with the Step & Direction method of driving the SureServo AC Servo Amplifiers.

However, I can't see how that can be done with the Kanalog board outputs. I've looked at the example of Geckos being interfaced, and that one seems to use connectors directly from the KFLOP board, rather than signals on the Kanalog board. Is that the only way to do this for Step and Direction outputs? Is there a breakout board to conveniently access those J4 & J5 terminals?

I'm wondering if I'd be better off using the analog +/-10 option if that's the case, because this is starting to look very messy.

What's the best way to go about this?

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TomKerekes
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Joined: Mon Dec 04, 2017 1:49 am

Re: Kanalog with SureServo AC Servo and Linear Scales

Post by TomKerekes » Sun May 02, 2021 12:25 am

See here.

Yes there are 3rd party break out boards. Winford.com is a source.
Regards,

Tom Kerekes
Dynomotion, Inc.

RogerFroud
Posts: 78
Joined: Tue Mar 30, 2021 8:07 am

Re: Kanalog with SureServo AC Servo and Linear Scales

Post by RogerFroud » Sun May 02, 2021 3:02 pm

Thanks Tom.

Ok, I've looked into this a bit more, and it would appear that I need to use a differential line driver for the Optically Isolated SureServo inputs for Step and Direction that are expecting a minimum of 5V.

It looks like I can use a SN75ALS174 powered from J4.1 VDD5 to convert the 3V3 digital output signals from JP4 to create differential signals at 5V which are compatible with the optically isolated SureServo inputs. That ought to create a reliable connection from the 3V3 digital outputs.

So, just to make absolutely certain we're reading from the same page about this implementation can I do the following...

1) Use KFLOP J4.1 to power the line drivers
2) Allocate KFLOP J4.5 (IO16_3V) to X-Axis Step
3) Allocate KFLOP J4.6 (IO17_3V) to X-Axis Dir
4) Allocate KFLOP J4.7 (IO18_3V) to Y-Axis Step
5) Allocate KFLOP J4.8 (IO19_3V) to Y-Axis Dir
... and so on for Z and A axes too.
Are there any software restrictions about what pins can be allocated to the Step & Direction outputs for the 4-axes I need?

What about the drive enables? They can be ganged together, and presumably connected to any of the KANALOG JP13 Opto outputs?
Are there any restrictions on allocating these in the software configuration?

The same question applies to the Spindle control. Can I use KANALOG JP13 Opto outputs to select Spindle FWD and Spindle REV? Grounding either of them acts as the Enable plus direction control.

And finally... for now...

The only feedback I intend to use is from the Linear Scales. I'm not intending to use the encoder outputs from the SureServo AC Amplifiers.

So to be crystal clear... the Servos are to be driven by Step & Direction pulses from the KFLOP JP4, and the position feedback is to be only from the Linear scales on the KANALOG JP1/2
Is that definitely ok?

Again, sorry to labour the point, but there's no way I want to design PCBs or interface only to find that I've misunderstood this and you can't do what I've implemented.

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TomKerekes
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Re: Kanalog with SureServo AC Servo and Linear Scales

Post by TomKerekes » Mon May 03, 2021 8:01 pm

Hi Roger,
Ok, I've looked into this a bit more, and it would appear that I need to use a differential line driver for the Optically Isolated SureServo inputs for Step and Direction that are expecting a minimum of 5V.
Actually KFLOP will provide nearly 5V in open collector mode. The issue is the turn off Voltage is ~1.3V.
It looks like I can use a SN75ALS174 powered from J4.1 VDD5 to convert the 3V3 digital output signals from JP4 to create differential signals at 5V which are compatible with the optically isolated SureServo inputs. That ought to create a reliable connection from the 3V3 digital outputs.
That’s probably a good idea. It’s not clear what output Voltage that chip provides.
So, just to make absolutely certain we're reading from the same page about this implementation can I do the following...

1) Use KFLOP J4.1 to power the line drivers
2) Allocate KFLOP J4.5 (IO16_3V) to X-Axis Step
3) Allocate KFLOP J4.6 (IO17_3V) to X-Axis Dir
4) Allocate KFLOP J4.7 (IO18_3V) to Y-Axis Step
5) Allocate KFLOP J4.8 (IO19_3V) to Y-Axis Dir
... and so on for Z and A axes too.
Are there any software restrictions about what pins can be allocated to the Step & Direction outputs for the 4-axes I need?
no, there aren’t Step/Dir signals available on those pins. See here.

What about the drive enables? They can be ganged together, and presumably connected to any of the KANALOG JP13 Opto outputs?
That should be possible if the total current is 25ma or less. It may defeat opto isolation between the drives.
Are there any restrictions on allocating these in the software configuration?
no, as those are handled by software.

So to be crystal clear... the Servos are to be driven by Step & Direction pulses from the KFLOP JP4, and the position feedback is to be only from the Linear scales on the KANALOG JP1/2
Is that definitely ok?
yes
Regards,

Tom Kerekes
Dynomotion, Inc.

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