SDC2130 Encoder setup trouble

6 years 5 months ago #29529442 by ldavisfl
I am having trouble getting my speed to show up on the Motor Control Utility.

I have my encoder powered from a power supply for now, and it is outputting the expected waveforms (as checked on Oscilloscope).

I have the output channels connected to pins 4 and 8. (Channel A and B, respectively.) I am only using Motor Channel 1.

I have disabled the RC1 and RC2 (since they are on the same pins as ENC1A and ENC1B). I have entered in my CPR (334 in my case) and set the encoder to feedback mode for Channel 1 only. (Channel 2 remains unchecked).

I can run the motor in open mode but I can not get the data recorder to report any RPMs other than zero.

Just to be sure, under the RUN tab I have tried deselecting the Analog and Pulse In Inputs, and the Digital Inputs. No dice.

The only possible reason I can come up with is that the encoder output wave form is not quite reaching 5V. How particular are the encoder inputs?

As I am new to this controller, I am hoping my problem is something trivial that I have missed.

Thank you.

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6 years 5 months ago #29529443 by ldavisfl
Adding to this a bit more...

The manual lists some requirements for encoders:

1. Two quadrature outputs (Ch A, Ch B), single ended or differential signals CHECK
2. 3.0V minimum swing between 0 Level and 1 Level on quadrature output CHECK
3. 5VDC operation. 50mA or less current consumption per encoder (I ASSUME THIS IMPLIES THE USER IS TRYING TO SUPPLY POWER FROM THE 5V/100mA OUTPUT PIN ON THE CONTROLLER. IF ONE HAS ANOTHER POWER SOURCE, THIS ISN"T TECHNICALLY A REQUIREMENT.)

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6 years 5 months ago #29529448 by ldavisfl
I discovered the problem and want to feedback in case it helps others.

The controller requires 3V differential from the encoder. My output measured over 4V peak to peak. However, I realized (using o-scope) that this peak to peak was including noise, and the actual peak to peak was something around 2.9V.

My encoder runs on 3.3V +/- 5%. Therefore, I increased the supply voltage (power supply) by 5% to the top of it's range and this caused the output differential to reach 3V, at which point the controller detected it.

I wish the sensitivity level of the encoder input could be adjusted.

I hope this helps someone.

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6 years 5 months ago #29529449 by Griffin Baker
Replied by Griffin Baker on topic SDC2130 Encoder setup trouble
It is recommended that you supply the 5V from the controllers internal 5V. That is on pin 14 of your I/O connector.

But if your encoder uses 3.3V operating range it would definitely be different.

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6 years 5 months ago #29529450 by ldavisfl
I am trying to inquire if I can drive the encoder at 5V, or if this would damage the encoder.

I don't suppose you will consider adding a user-selectable voltage on pin 14? :)

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6 years 5 months ago #29529451 by Griffin Baker
Replied by Griffin Baker on topic SDC2130 Encoder setup trouble
What you can do is create a voltage divider much like what is used on an analog device (potentiometer).

So lets' say you take a 5K potentiometer and wire that to +5V and Ground. The center tap wiper wire is the voltage you can adjust by turning the pot, and this same wire is where it would connect to the encoder lines.

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