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Quadrature scales on the mixed scale kit
#1
   
Hi All,

I thought that I would put down some notes on the steps needed to use quadrature scales on the mixed scale kit.

Firstly, lets be clear you cannot use quadrature and other scales together on this kit as they need different firmware inside the microcontroller. So it's either Quadrature on all the axis inputs or on none. I could have  downloaded the firmware from Yuriy's website and then burnt it into the microcontroller but instead I bought a microcontroller pre-programmed with the quadrature firmware. 

Most Quadrature scales need 5 volt power and this isn't directly available from the mixed signal kit. Providing you are powering the kit from a regulated 5V source it can be modified to supply the scales. The modification requires the removal of two 220R resistors and adding an insulated wire link. Once completed the jumper shunt that used to be for selecting 3.3V scales is now used to select 5V scales. 

The axis scale D pins are now A and the C pins are now B.
The + pins are 5V and  ground is still ground.


Unfortunately the LM339 will now have trouble with the new signal levels and four of the 47K resistors will need to be changed to 24K.

The PCB components are not numbered and it makes it difficult to describe. 
I have attached a JPG that makes it clearer.

Bob
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