Hello !

3. So, the total resolution will be 26-bit (24-bit + 2-bit) = 67108864 ?

Regards,

Berg

Technology Team

Hello,

internally, the encoders position actual value (Gn_XIST1) is calculated as follows:

r479 (Gn_XIST1) = p408 (pulse number) * 2^(p418 fine resolution)

Is doesn't make sense to increase the fine resolution manually and extend the hardware capabilities by that. That means for TTL/HTL encoders a fine resolution of p418 = 2 is sufficient and for sin/cos encoders a fineresolution of p418 = 11. I cannot recommend to extend it manually.

The relationship between  the encoders pulses, fine resolution and multiturn resolution is described well in the document that you attached. The maximum value which can transferred to the PLC is 32 bit.

That means the sum of all the three values (encoder pulses, fine resolution, multiturn resolution) needs to be below 32 bit. There is an example of an encoder in the document with 2048 pulses (11 bit) and a multiturn resolution from hardware that is 4096 revolutions (12 bit). Then you can calculate the last part which is left for the fine resolution:

32 (maximum) - 11 - 12 = 9 bit for the fine resolution

That means in case you would need a higher fine resolution (in order to get a higher accuarcy within one revolution) you have to decrease the multiturn resolution (but then you have to make sure that the number of revolutions are still enough to cover the full range of motion of the mechanic). Of course the extension should not exceed hardware limits again.

I hope that this explanation helps you! 

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Split from S120 - Fine resolution p0419 (XIST_1).