ENCODER INSTALLATION: INDEX PULSE PROBLEM

[BioAgeLtd]

Post the EXACT Make and Model number of the Encoder you used on the spindle as well.
Without pictures, we can only ASSUME you belted the encoder with a timing belt to the spindle at 1:1 (REQUIRED)

Post the make and model of the encoder.
Post a picture of the encoder belted to the spindle at 1:1 please
Post the fresh report.
Providing this information will get you better suggestions to help you.

Marty

Dear Marty,
please find attached a picture of the encoder, it is connected to a auxiliary shaft that turns
ALWAYS at the same rpm of the spindle, I've tested it

I've attached the report saved according to your suggestion.

The encoder is an AUTONICS E40S8-5000-3-T-24, please note that it is an encoder
working at 24Volt with the unbalanced signals, but in our company we have designed
and realized an electronic circuit that translate the signal at 5V, with balanced signals
for each channels, we have tested all the output signals with the oscilloscope and
these are fine, I've attached the datasheet of the encoder.

Thanks Best Regards Stefano

[BioAgeLtd]

Please post a report.

Go into the PID menu and watch the encode fields, when you rotate the spindle does the encoder count?
When the index pulse present, an asterisk will appear next to the label for the axis that the encoder is counting on

Dear Marty,
I've noticed that the asterisk never appears on the pid screen, so I suppose that there an hardware problem in
the electrical connections of the index pulse.

Thank you very much for your help, I will update you when I will resolve the problem

Best Regards Stefano

[BioAgeLtd]

Please post a report.

Go into the PID menu and watch the encode fields, when you rotate the spindle does the encoder count?
When the index pulse present, an asterisk will appear next to the label for the axis that the encoder is counting on

Dear Marty,
I've noticed that the asterisk never appears on the pid screen, so I suppose that there an hardware problem in
the electrical connections of the index pulse.

Thank you very much for your help, I will update you when I will resolve the problem

Best Regards Stefano

Dear Marty,
I've found a problem due to an electrical soldering on the electronic board that we have realized
in order to adapt the electrical signals of our encoder, now all seems to work fine and I've found
the asterisk on the PIC screen. In the next days I will try to set the parameters related to the
threading and tapping processes.

I've attached the schematic of the electronic board that we have designed and realized in order
to connect an encoder working at 12V or 24V with unbalanced outputs (A, B, Z), and also a picture
of this board installed into an aluminium enclosure in order to shield it, if it can help other people
then you can share these files.

Let me know if you want to receive also the Gerber files of the PCB that we have designed.

Thank you very much for your help I wish you an happy new year Stefano

[BioAgeLtd]

You can see if the index pulse is being detected by watching for the asterisk as Marty and I suggested.

Since you're turning the spindle by hand, timing won't be an issue. All you to do is confirm that it flashes exactly once per revolution

Thank you very much for your help, I can't see the asterisk related to the index pulse when I turn
manually the spindle, so probably it is related to a problem of the electrical connections, I will try
to solve it and then I will update you

Thanks Best Regards Stefano

Thank you very much for your help, I've solved my problem, to have more info about please
read my reply to Marty.

It is the first time that I've asked for an help, and your support has been fast and efficient

Thanks I wish you an happy new year Stefano

[BioAgeLtd]

Post the make and model of the encoder.
Post a picture of the encoder belted to the spindle at 1:1 please
Post the fresh report.
Providing this information will get you better suggestions to help you.

Marty

Dear Marty,
please find attached a picture of the encoder, it is connected to a auxiliary shaft that turns
ALWAYS at the same rpm of the spindle, I've tested it

I've attached the report saved according to your suggestion.

The encoder is an AUTONICS E40S8-5000-3-T-24, please note that it is an encoder
working at 24Volt with the unbalanced signals, but in our company we have designed
and realized an electronic circuit that translate the signal at 5V, with balanced signals
for each channels, we have tested all the output signals with the oscilloscope and
these are fine, I've attached the datasheet of the encoder.

Thanks Best Regards Stefano

Dear Marty,
I've found a problem due to an electrical soldering on the electronic board that we have realized
in order to adapt the electrical signals of our encoder, now all seems to work fine and I've found
the asterisk on the PIC screen. In the next days I will try to set the parameters related to the
threading and tapping processes.

I've attached the schematic of the electronic board that we have designed and realized in order
to connect an encoder working at 12V or 24V with unbalanced outputs (A, B, Z), and also a picture
of this board installed into an aluminium enclosure in order to shield it, if it can help other people
then you can share these files.

Let me know if you want to receive also the Gerber files of the PCB that we have designed.

Thank you very much for your help I wish you an happy new year Stefano

[martyscncgarage]

Glad you found the electrical issue with the index pulse, but I think you are going to have issues because that encoder is NOT belted TO the spindle at 1:1 with a timing belt. Gears have lash....

[cncsnw]

I doubt that gear lash will have a significant impact. The amount of lash should be a very small fraction of a revolution.

In the worst case -- if it seems that the encoder is bouncing or oscillating within the lash range as the spindle runs -- you could add a little drag to the shaft so that it always takes some positive torque to drive it.

Backlash in the encoder drive for a servo motor's position encoder would be bad news. But for a spindle encoder, I would not worry too much about it.

[BioAgeLtd]

I doubt that gear lash will have a significant impact. The amount of lash should be a very small fraction of a revolution.

In the worst case -- if it seems that the encoder is bouncing or oscillating within the lash range as the spindle runs -- you could add a little drag to the shaft so that it always takes some positive torque to drive it.

Backlash in the encoder drive for a servo motor's position encoder would be bad news. But for a spindle encoder, I would not worry too much about it.

Thank you very much for your useful suggestion, it seems that the gear is quite tight, anyway if during the tests I will fine some
problem due to the lash then I will change the encoder setup according to your suggestion

Best Regards Stefano

[BioAgeLtd]

Glad you found the electrical issue with the index pulse, but I think you are going to have issues because that encoder is NOT belted TO the spindle at 1:1 with a timing belt. Gears have lash....

Dear Marty,
thank you for your suggestion, If I will notice this problem then I will update the encoder fixing following your setup

Best Regards Stefano

[Muzzer]

Rather than make up an interface using NOT gates, you'd be far better off using a dedicated line driver. There are loads of these on the market that are designed specifically for differential lines. Search for "RS422 RS485 differential line driver", instead of trying to reinvent a wheel.
https://www.digikey.co.uk/catalog/en/pa ... iver/11774
https://web.archive.org/web/20180517101 ... yt484a.pdf
The thresholds for RS422/485 aren't the same as std TTL and the standard allows for a much higher common mode voltage range, which is a key part of the noise immunity that this standard is trying to achieve.