PLUS+1™ Hardware > Controllers

QUAD COUNT ERROR

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pinias:
hey Guys,

I have looked at another post talking about the quad count error, but does not may give me a clue the reason of the error I have.

Basically I am reading an encoder with a MC012-110, pin 8 is A+ and pin 9 is B+ , the encoder is 5 volts powered by the controller.  1 rev is 360 pulses.

Now when I rotate the wheel clockwise i count 360 pulses per revolution, no matter the speed, it always counts correct.

then, turning the wheel counterclockwise I always loose 2 pulses per revolution, each rev it only counts 358 pulses.


we did another test, we connected B- to pin 9 and we left A+ to pin 8.

turning the wheel clockwise it did read 358 pulses it lost 2 pulses, each revolution, it never counted 360

turning counterclockwise it reads 360 pulses always.

basically the issue was inverted... this tell us the problem may be the pulse count at the pin itself.

has anyone ran into this issue?  why does it could loose 2 pulses in one direction and none on the opposite direction?

did you find a fix for that?

thank you for any advise

pinias:
Well,

I am thinking loud, when changing direction, I can see I can loose a couple of pulses, however after keep moving in the same direction it should get corrected, isn´t?

now if my formware is wrong, why when I connected B- the issues get reversed and it is always present?

pin8 is where the pulses are detected, pin 9 only looks for direction. So if my firmware is wrong I should see the issue all the times, am I correct?

just thinking a little more about



SJ Industries:
Do you have a truth table for the encoder?

I use a 2 bit rotary encoder in some of my projects in place of a potentiometer dial, if the RPM is  too slow or the pulse count is low per rpm the quadcount wont work properly.

If you are using a 4 bit encoder perhaps the lost pulses are due to the sequence output from the encoder?

pinias:
Hey SJ

I have looked for the truth table but so far no luck on that.

no matter if I connect A+ and B+ or A- and B- the result is always the same 2 pulses less.

I have tried with another encoder and same results

SJ Industries:
Can you try A+ and A-. I think because you are only using 2 outpus of a 4 output encoder you are missing pulses. If you had pins enough you could use A+ & A- on one pair and B+ & B- on another pair and that would be CW & CCW on corrosponding channels. The Danfoss control "should" indicate direction anyway but you just use the one "A" channel.

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