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Facet times

A project log for open hardware fast high resolution LASER

bringing additive manufacturing to the next level

HexastormHexastorm 09/26/2019 at 16:220 Comments

Good news! I received the NBC31111. The facet times look to be good and the motor is quiet again.
In other words; the laser module is working once more.
I have quite a busy weekend ahead, but will try to make a new exposure on Monday.

The facet times are;

Note that i ignore the first 100 lines as the prism doesn't seem to be stable enough.

output from script:
---------------------------------

In total, sent 1600 lines
Error received; ERROR_NONE
The expected hsync time is 12500
The facet series are
Item: 100
12592 12590 12589 12592 12592
12395 12396 12395 12396 12395
12408 12408 12410 12410 12409
12594 12597 12596 12596 12597
Item: 116
12592 12591 12590 12592 12593
12395 12396 12396 12395 12395
12409 12409 12410 12410 12408
12597 12597 12595 12595 12597
Item: 132
12593 12590 12589 12593 12592
12395 12396 12396 12395 12395
12408 12409 12410 12409 12408
12597 12598 12595 12596 12598
Item: 148
12592 12589 12591 12593 12590
12395 12396 12396 12395 12396
12408 12410 12410 12409 12409
12598 12597 12595 12596 12597
Item: 164
12590 12590 12592 12591 12589
12396 12396 12396 12396 12396
12409 12410 12409 12409 12410
12597 12595 12596 12597 12597
Item: 180
12589 12591 12593 12590 12589
12396 12396 12395 12395 12396
12410 12410 12408 12410 12410
12597 12594 12598 12598 12595
Item: 196
12589 12592 12590 12590 12593
12396 12396 12396 12396 12396
12410 12409 12410 12410 12409
12595 12596 12597 12595 12595
Item: 212
12593 12592 12589 12593 12591
12396 12395 12396 12395 12396
12409 12409 12410 12409 12409
12595 12597 12595 12596 12597
The counters are [376, 1123]
Test passed, can bin all times

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Earlier, I reported that the facet times recorded by the diode can be used to determine the facet number.  In the above, you can see that one facet has facet times smaller than 12400.

If the jitter allow per period is set very small, no difference can be perceived in facet times. For the proof of concept module, I used a jitter allow of 1/3200. All the facet times are then very similar and jitter is quite minimal.
With a jitter allow of 1/100, I can determine the facet and use an interpolation table to reduce the jitter.
I am not sure which strategy works best, but I do claim I possibly use one of these methods.
I also claim I use information by an acceleration sensor to determine whether my prism is rotating smoothly or an earthquake is interrupting operation. I also claim I use this information to correct the data sent to the prism scanner by calculating a more accurate position.

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