1769-hsc

doing a some workbench testing...

I'm using a vfd with a 1750 rpm motor.. I ran a cog belt pulley from the motor to a shaft at 1 to 1. I attached a 100 ppr differential encoder to the shaft side pulley.. I had the encoder laying around so I used it.. I have no filter setting for the HSC. In operational mode I'm using encoder x2

When I have the hz set at 25hz and the encoder is set for say 500 pulses I get a travel of say 1 foot. if I lower the hz to 10 and set the encoder to the same 500, I only get 10 inches of travel..

It is the low resolution of the encoder??? is it the update time in the set up??? Encoder x2???

Why would changing the hz lower cause the travel to be different??? Am I just missing pulses at the higher hz???

I would think it would travel the same distance but only slower?? Or Am I really missing the picture???

Thanks
Brad

I'm not sure what you mean by "getting 1 foot of travel".

Do you mean that you're starting the drive, running the HSC, then stopping it when the HSC reaches its preset ?

If so, then the time to decelerate to a stop is probably the difference.

10 Hz -> 0 Hz takes less time at the same deceleration rate than 25 Hz -> 0 Hz.

If you're starting the counts at the same time as you're starting the drive, then there's an effect both from the acceleration and from the deceleration parts of the motion profile.

First, thanks!!

for taking the time reading and processing what i was trying to ask...!!! I see it can be tough!!

Yes!! I'm running the drive to a preset!! sorry I didn't make myself clear...

As for travel?? I really wasn't sure how to express it as you noted. I went primitive and taped a vinyl measuring tape to the other end of the shaft with the encoder to just see if I would get the same measurement when I changed the hz..

I'll adjust the accel and decel to see what results I get..

thanks again for pointing me in a direction!!!