View Full Version : Encoder - Decoder

07-24-2003, 02:26 PM
I have a few stepper motors that have encoders one one side of them, Does anyone have a schmatic or know where to get a 3 chanel encoder interface board for around 100$

Do most Encoder interfaces use serial, parrelle or ISA/PCI??

Mariss Freimanis
07-24-2003, 10:09 PM
Most 3 channel encoders are quadrature output (2 channels) and an index channel.

The quadrature output (channel A and channel B) have the following output (CCW):

A 0011001100..
B 0110011001..

The CW output is the reverse:

A 0011001100..
B 1001100110..

These outputs are usually decoded by a quadrature decoder to give a "step" and "direction" output (or CLK and U/D signal for counters).

The index channel gives a single output pulse once a revolution and is generally used to give an accurate "home" position.


07-25-2003, 03:44 AM
Hello bcromwell

You may build simple 8 bit up/down counter using standart
CMOS IC and you can read the counter outputs from the PC
paralel port.(You must write simple software)

CHA feeds the UP/Down input, CHB feeds the clock input.

This method use the shaft encoder in x1 mode.