7i73 Encoder input velocity

Hi,

how can i read the velocity signal from the encoder input of a 7i73?
On the 7i76 there is a corresponding hal pin. On the 7i73 there is unfortunately no hal pin.

Kind regards
Roland

roland wrote:

Hi,

how can i read the velocity signal from the encoder input of a 7i73?
On the 7i76 there is a corresponding hal pin. On the 7i73 there is unfortunately no hal pin.

Kind regards
Roland

If you review the manual, the encoders are for MPG's so they don't have the full range of pins the 7i76 spindle encoder has. With MPG's you just work with counts. You probably need a 7i85 to add spindle encoders.

Right, the 7I73 encoder inputs are just intended for MPG use so they do no velocity estimation (you can use D/DT of count for a crude velocity estimate)

I've tried this with ddt now.
From a count rate of 2000 Hz or higher this works quite well with ddt and a lowpass filter.
My count rate is 0 to 1000 Hz. There the velocity signal is not stable.

Well the lower speed you go, the longer time constant you would need on your filter for a stable velocity, If this is for a MPG, a 50 ms or so time constant should be OK