Encoder ppr?

I used these:
HEDR-55L2-BY07 3600 ppr 14400 cpr. with the 7i40 hbridge the positioning accuracy is + or - 0.001 mm, which is not possible with an encoder with less resolution I think.
closed loop servo-thread 8khz
pay attention, however, that the maximum frequency of these encoders is 320 khz,
for me it's fine because I go to more than 100 mm / s
regards
Mauro

The highest frequency seems to be 300 kHz on the COLT encorders.
Certainly, is the correct type of output on these transducer sensors?

Model GHST58-06-G-3600-B-M-T-5- may work

CALT 3600ppr 5000 pulse 6mm shaft servo flange optical encoder

PCW wrote:

I get 3600PPR @3000 RPM = 50 RPS* 3600 = 180 KHz A/B signals and 720 KHz count rate (4X 180KHz)

at 5 mm/turn and 4X3600 counts per turn that's ~0.347 microns per count

I do not understand why 180kHz is multiplied by 4.

The count rate is 4X the A or B frequency because
in (normal 4X) quadrature all edges of the A and B
signals are counted.

When you measure frequency you measure the number
of cycles per second, where each cycle  has a rising and
falling edge, so the number of edges per cycle is double
the number of cycles. When you do this on both A and B,
you end up  with 4 edges per cycle.