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Anyone with experience or info on reading/decoding quadrature tacho?

Gears Valued Contributor Gears Valued Contributor
Gears Valued Contributor

I have been asked to add a tacho with a quadrature output, with 4x upscaling/upsampling, to substantially increase the resolution of our tacho signal(s).  I haven't done much with our tacho signals, beyond the typical zebra tape or once/rev laser tachs.

 

Can anyone post info on reading/decoding a A/B quadrature signal with counting leading edges of both to upsample the signal 4X?

 

Thanks,

Shelly

 

4 REPLIES

Re: Anyone with experience or info on reading/decoding quadrature tacho?

Siemens Legend Siemens Legend
Siemens Legend

 Hi Shelly,

 

I think you need a RV4 card for this tacho measurement. 

Here I attach a picture with the pin layout:

Picture1.jpg

Is it an incremental encoder signal you're measuring?

 

Hong

Re: Anyone with experience or info on reading/decoding quadrature tacho?

Gears Valued Contributor Gears Valued Contributor
Gears Valued Contributor
Yes - incremental encoder measuring rotation, outputting two digital pulses, 90° out of phase.

I think there are 128 pulses/rev, with an output of leading edges for each pulse signal, to allow 4X the initial resolution.

Thanks for the info!

Re: Anyone with experience or info on reading/decoding quadrature tacho?

Siemens Legend Siemens Legend
Siemens Legend

Hi Shelly,

 

Here's a FAQ regarding to Incremental encoder measurement in Test.Lab: https://solutions.industrysoftware.automation.siemens.com/view.php?sort=desc&p=1&q=incremental+encod...

I'll send you the product information sheet for the RV4 card in an email.

 

Hong

Re: Anyone with experience or info on reading/decoding quadrature tacho?

Gears Valued Contributor Gears Valued Contributor
Gears Valued Contributor
Excellent! Thank you.

I was just fumbling through Siemen's website trying to find info on the RV4 card, under LMS/LMS Testing Solutions/etc... I love this forum, but find their website rather tough to navigate when searching for specific info on a product.