Quadrature Encoder Issue

Using encoders with the MCP product line
john.dumbauld
Posts: 2
Joined: Tue Apr 03, 2018 11:21 am

Quadrature Encoder Issue

Postby john.dumbauld » Tue Apr 03, 2018 11:36 am

I am attempting to use the MCP260A to control 2 separate motor/encoders. I have successfully connected one pair consisting of: https://www.anaheimautomation.com/manua ... 0Index.pdf and https://www.andymark.com/CIM-Motor-p/am-0255.htm. I have these components as M1 & ENC1 and can read/control them in IonStudio.

I am, however, having difficulty connecting this motor/encoder: https://www.servocity.com/313-rpm-hd-pr ... -w-encoder to M2 & ENC2. In IonStudio I have control of the motor but am not receiving encoder info. I have verified the encoder is receiving +5v from MCP and it is returning +-1.6v signal. Regardless of which input mode I set DIN8 and DIN10 to, I get no signal in IonStudio.

I noticed in this document: http://downloads.ionmc.com/docs/mcp260_datasheet.pdf that DIN7 and DIN9 have ENC1A / HALL1 input and attempted swapping the motor/encoder pairs, to no improvement.

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Basicmicro Support
Posts: 1094
Joined: Thu Feb 26, 2015 9:45 pm

Re: Quadrature Encoder Issue

Postby Basicmicro Support » Wed Apr 04, 2018 9:59 am

The encoder should not be returning +- 1.6v. It should never go lower than 0v at any given moment. If it is going to -1.6v there is a problem with it.

However if I remember correctly those motors, with the hall sensors built into them, output a pretty low high signal(around 2v) which is too low by itself for the MCP to read. Add a pull-up resistor(1k,4.7k or possibly a 10k) from each signal line of the sensor to 5v. This should raise the signal to a higher point to make it readable by the MCP.

Note if the signal still goes negative at anypoint even with the pullup then there is a problem with the sensor.

john.dumbauld
Posts: 2
Joined: Tue Apr 03, 2018 11:21 am

Re: Quadrature Encoder Issue

Postby john.dumbauld » Fri Apr 06, 2018 6:01 pm

Thank you for the prompt and accurate feedback! After implementing your suggested fix, using the 4.7k resistor, I am now reading quadrature counts from the encoder. My mistake on the signal voltage.


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