Spindle and encoder

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16 Aug 2023 19:05 - 16 Aug 2023 19:06 #278194 by smplc
Replied by smplc on topic Spindle and encoder
It may depend on the inset diameter of the encoder too.

I might just want to go with a differential rotary encoder that includes a shaft, pulley, belt and bracket. The code wheel and transducer are enclosed and should be calibrated. I'll have to shop around. I have yet to know if I need to manufacture or buy the pulley and bracket. The process might be about a few weeks project.
Last edit: 16 Aug 2023 19:06 by smplc.

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17 Aug 2023 01:24 #278221 by JPL
Replied by JPL on topic Spindle and encoder

The noise makes me think either there is some issue with the
disk (low reflectivity of white or too high reflectivity of black)
or the signal does not reliably swing close to ground
 


I wanted to add to what PCW wrote that you can also compare your signal with this one using the same encoder: forum.linuxcnc.org/39-pncconf/45140-encoder-spindle-help#235191

Note that kbec signal is not only noiseless but also that the high and low (on/off) are really about the same width on the hal scope. Your is not, ON width are much narrower than OFF width. I'm wondering if this could be related to the way your sensor is connected or powered?  

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17 Aug 2023 03:10 - 17 Aug 2023 03:45 #278223 by smplc
Replied by smplc on topic Spindle and encoder
It appears the link has a better signal than me. I wonder if it’s partially due to the version firmware. It looks like the link could have used the same code wheel I started with. I’ll inspect dimensions of LEDs and code wheel lines. What does the M integer represent in the link formula? I have some doubt the power source is a discrepancy because I tested the encoder and 7i96s pins high and low voltage with multi-meter and receive acceptable readings earlier in this string.  I tested and received resistance each end of the encoder cable terminal connectors.  The connectors and wires to the 7i96s look acceptable.  I wonder if the Masso Optical Encoder and 7i96s lack compatibility.
Last edit: 17 Aug 2023 03:45 by smplc.

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17 Aug 2023 04:54 #278228 by PCW
Replied by PCW on topic Spindle and encoder
The signal in the kbec thread is much cleaner and probably fairly functional.
The encoder interfaces are identical so that suggests an issue with the disk
or detector.

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17 Aug 2023 05:07 - 17 Aug 2023 05:09 #278229 by smplc
Replied by smplc on topic Spindle and encoder
In that case I’d like to see if I can spare the Masso encoder and see how it does. It appears the issue now might start with the code disk. I understand the link of the formula to space A and B LEDs except the variable M. What integer does M represent? Is it just additional spacing and some random number?
Last edit: 17 Aug 2023 05:09 by smplc.

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17 Aug 2023 06:07 #278232 by JPL
Replied by JPL on topic Spindle and encoder
M is just the number of cycles (could be zero) But I think you are chasing the wrong problem, I mean you tried with the disk from Sherline, then one from the Masso app. You still have spikes/noise in the signal and the On Off states of the signal are not evenly balanced (50% On / 50% Off).

If you can find a way to have both the A and B signal corrects. This is: No spikes/noise, off state width same as on state width, then this will worth spending a bit more time to adjust the phasing between the 2 signals.

Sadly there's very few info on the Masso website. The only think I've found is this:CAUTION: Output signals are 0v for LOW signal and 10v for HIGH signal. Do you have some documentation provided with the encoder?

You also wrote previously that the signals of the encoder are TTL: Are you 100% sure of that?
About the output voltage you wrote: Output Signal Z 9.5VDC, Output Signal B 9.49VDC, Output Signal A 9.52VDC. But encoders input of the Mesa card are rated 5.0V... Do you have a voltage divider or similar to reduce the voltage to an acceptable level for the Mesa card?
Also, as PCW mentioned before, 0v is important too. Did you measure the low signal too?
And since this is a common thing to forget: Did you connect the common (0v) of the power supply for the encoder to the Vfield common of the Mesa card?

(Note: Do not run the spindle when measuring High and Low signal from the encoder, just manually align the disk to the white and black spaces )






 

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17 Aug 2023 07:34 #278237 by smplc
Replied by smplc on topic Spindle and encoder
It seems I’ve tried about all I do to remedy the Masso encoder. I’ll probably try another encoder as mentioned earlier.

The Masso encoder high and low signals are at docs.masso.com.au/wiring-and-setup/setup...asso-optical-encoder .

Yes, the Masso encoder is single-ended and only uses TTL signals. It has no A-, B- and Z- terminals. I bought the encoder from Sherline in it came in a kit for the lathe. Masso and or Sherline made a cable with one end a pig tail for P1, P2 and P3 and P3 shares the same ground terminal as the encoder at the connector. The other end of the cable is ground-off at the DB9 exterior connector. I made a cable with one end ground-off at the DB9 exterior connector too. And the other end is a GX16 8 pin circular connector. The 13VDC output regulator ground wire is soldered to one of the GX16 8 pins.

Yes, I did measure the encoder low signals and they were 0.25VDC as indicated earlier.

Yes, the Mesa 7i96s is powered with it own 5VDC power supply.

The Masso encoder accepts 12VDC-24VDC. The output voltage is the same high and low regardless the specified input voltage. The output voltage might alter if such a transistor were replaceable. I think earlier in this string PCW indicated the Masso encoder usable regardless it high at 10VDC.

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17 Aug 2023 07:52 - 17 Aug 2023 08:05 #278238 by JPL
Replied by JPL on topic Spindle and encoder
Ok, that seems to be correct and I've checked that PCW indeedd mention that up to 10v was ok.

Just on thing is unclear to me. Did you also connect the ground (common) from the masso encoder to the ground of encoders of the mesa card?
Last edit: 17 Aug 2023 08:05 by JPL.

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17 Aug 2023 08:10 #278239 by JPL
Replied by JPL on topic Spindle and encoder
@PCW: What is the correct way to connect single ended encoders? Should the A- B- and I-  terminal on the mesa card be left floating or grounded? (Or it doesnt matter as long as the jumpers are set correctly)
 

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17 Aug 2023 10:52 #278253 by smplc
Replied by smplc on topic Spindle and encoder
No, because as mentioned earlier the encoder cable, male terminal block, ve- (ground) pin and other end of the cable the ve- wire is ground-off on the female DB9 exterior connector. Pardon me, I mistaken the P3 wire and ground pigtail wire when I was long-distant from my equipment earlier this morning. Actually, a pigtail is just another ground wire the male terminal block shares with the ve- pin. The pigtail probably is if the ground isn't going to the power supply and for instance to the chassis or headstock instead and reassure the ground is cycling. That's actually how Masso or Sherline made the cable. However, the ground is coming from the voltage regulator with my setup. I made a cable and the other end is ground-off on the male exterior DB9 too that connects to the female DB9 encoder cable. The P1, P2 and P3 actually are individual pins and P3 not sharing ground (common, ve-).

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