BOSS 6 resolution question

[Agmachines]

What was/is different in the BOSS 6 to achieve the .0005 resolution, up from the .001 in the previous BOSS series?
The driver SMD cards seem to be the same part number, as for the prior series, 027015. The number of steps per inch would appear to be 2000, for the stepper motors, and this carries through when the logic cards are removed for a retrofit. In the prior versions of the BOSS machines 1 thru 5, the steps were 1000 per inch.
My question is; where in the driver to stepper components does this extra resolution, or steps, reside?
Thanks,

Russ

[gus]

did I read that it is the pulley?

[machintek]

I know that the boards are different. Ths LSI is the same. The clock card is different (ZCK vs RCK), The ERS is different (the BOSS software resides in it). The interface card id different (ZDI vs XDI). and the BOSS 6 has an additional board the NTP (number crunching).

George

[mactec54]

Hi Agmachines
The Boss5 are 1/1 motor to ballscrew and the Boss 6 has 2/1 there are
some Boards that are different, It's in the electronics that give it the .0005 resolution

[Agmachines]

Thanks!, Everyone.

The question came up, after a retrofit.
Before, I swapped out the logic cards for a retrofit, I had thought all the differences to get to the .0005 steps, resided in the different logic cards that the BOSS 6 contained, as George has enumerated.
I found after the swap, the drivers needed 2000 step input, as all my distances had been halved. In reading back through the archives, I had found others that noted the same. That difference must be in the pulleys as several have mentioned, since, the rest of the motion parts appear to be the same as the previous BOSS editions.
The question of the differences had been eluding me for several weeks.
I appreciate the input.

Russ