Re: A question for Don

Russell R

Hi Dan,

I was talking about how an absolute encoder works, unlike an incremental encoder which just counts ticks, absolute encoders always know it's position within 360°.  My concern is by changing the ratio of the encoder from the axis, how would it know it's position?  Maybe it would work, I just don't know.   I use a 64,800,000 tick Renishaw incremental encoder (413mm diameter) with dual read heads on the RA and built a circuit to use the index signal to initialize the mount in SiTech.  My motor ticks are almost the same.  I have always believed what good are lots of ticks on the axis if the motor ticks are not almost the same,  the accuracy would be no better than the motor ticks.  
65M ticks is plenty, with the cable there is some error and won't fully utilize the accuracy of that encoder.  Optimum is a direct axis mount or 1:1 in my opinion.

For high value inputs, you use the terminal window.

All commands must be in CAPS.

Open Servo Config and select the correct COM port.

Click Terminal Window

A window should pop up. Make sure you are communicating with the controller by pressing ENTER on the keyboard.  A string should appear in the format: X# Y# XZ# YZ# XC# YC# V# T# X[AM] T[AM]

Do not use commas or parentheses when typing ticks numbers


For Az/RA motor encoder ticks type: XXV(Ticks) and press ENTER 

Type XXV and press ENTER, you should see XXV(Ticks)

For Alt/Dec motor encoder ticks type: XXU(Ticks) and press ENTER

Type XXU and press ENTER, you should see XXU(Ticks)

For Az/RA mount encoder type: XXZ(Ticks) and press ENTER

Type XXZ and press ENTER, you should see XXZ(Ticks)

For Alt/Dec mount encoder type: XXT(Ticks) and press ENTER

Type XXT and press ENTER, you should see XXT(Ticks)


To save configuration, type XW and press ENTER.

Sometimes, SiTech don't like the input and you will have to ignore the warning.

I think it's great Dan, send some pics!!!

Clear Skies!
Russell R.

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