Spindle Encoder
03 May 2016 21:54 #74203
by paris_tj
Spindle Encoder was created by paris_tj
First off, excuse my ignorance, I am new to Linuxcnc.
I have a mill with a VFD belt drive spindle, and I want to add a spindle encoder to be able to monitor RPM and rigid tapping.
First, what encoder would you recommend I use for this? I will build/design my mounts and etc off this.
I have a mill with a VFD belt drive spindle, and I want to add a spindle encoder to be able to monitor RPM and rigid tapping.
First, what encoder would you recommend I use for this? I will build/design my mounts and etc off this.
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03 May 2016 22:09 #74205
by andypugh
Replied by andypugh on topic Spindle Encoder
The difficulty with a lathe spindle is that it has a big hole in the middle, so you either need an encoder with a big hole, or a belt / gear drive with a 1:1 ratio or to make your own encoder.
The latter can be cheap and effective. You may even be able to use a gear in the headstock if you have any, though you seem to be suggesting that you don't.
The problem with a commercial encoder is that they tend to have a lot of counts per turn. This isn't too much of a concern if you have hardware to count the pulses, but if you are using the parallel port then you need to consider your sampling rate and spindle speed and choose a counts-per-rev to match.
If you are making your own encoder disc then you can choose a slot-count to suit.
If you do buy an encoder, make sure you get on with an index pulse. There are some pretty cheap ones on eBay, www.ebay.co.uk/itm/111840562438 for example. (check the part numbers, but I think that is an ABZ encoder, ie three-phases including index)
That's a 100ppr one, you can go higher if you are not using software encoder counting. (if, for example, you are using a 7i76)
The latter can be cheap and effective. You may even be able to use a gear in the headstock if you have any, though you seem to be suggesting that you don't.
The problem with a commercial encoder is that they tend to have a lot of counts per turn. This isn't too much of a concern if you have hardware to count the pulses, but if you are using the parallel port then you need to consider your sampling rate and spindle speed and choose a counts-per-rev to match.
If you are making your own encoder disc then you can choose a slot-count to suit.
If you do buy an encoder, make sure you get on with an index pulse. There are some pretty cheap ones on eBay, www.ebay.co.uk/itm/111840562438 for example. (check the part numbers, but I think that is an ABZ encoder, ie three-phases including index)
That's a 100ppr one, you can go higher if you are not using software encoder counting. (if, for example, you are using a 7i76)
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