Waiting for VFD to spin up the spindle.

I'm using a huanyang vfd to drive my spindle motor. I'm controlling it from a 5i25/7i77 by sending a 0-10v signal on analogout5 to the VI on the VFD. That's all working fine.

However, the spindle takes a few seconds to get up to speed and if the mill is close to the starting point it's possible to engage the work before the spindle is moving fast enough. I have a broken end mill to prove it.

I'd like to read in the voltage output from the vfd (VO) and compare them to set the spindle-at-speed. When I read the VO from a multimeter, it reads 0-10V as expected. I connect it to analogin1 and read it through halmeter and it jumps back and forth between 0 and 10.1, never coming to rest anywhere.

That's as far as I've gotten but I'm sure I'll need to use near to compare them.

I'm kinda feeling my way blindly here so if someone could fill in the fuzzy areas I'd be grateful.

If your drive has a digital up to speed signal you can wire that to the hal pin motion.spindle-at-speed. This will cause the machine to wait until this pin is true beginning a cut.

Do you have a common GND between the 7I77s (isolated) I/O section and the VFDs analog section?

It has a multi-output port. If I understand it right, this is a relay that can be configured to close if the set frequency is reached. I've played with it and found it to be flaky. If the set frequency is a very different from the current frequency or changing fast, it trips about 80% of the time. If the change is small or changing slowly, it often never trips at all. This is a cheap chinese VFD but I also might have something wired/configured incorrectly.

If you mean a common ground between the field power connection on TB2 pin 8 and the ACM on the analog side of the VFD, then yes.

Is the analog output funny? I guess it could be a 7I77 analog input bug.

Can you check that the 7I77 input is OK?
Connecting one of the analog inputs to field power would be a good check

sliptonic wrote:

I'm using a huanyang vfd to drive my spindle motor. I'm controlling it from a 5i25/7i77 by sending a 0-10v signal on analogout5 to the VI on the VFD. That's all working fine.

However, the spindle takes a few seconds to get up to speed and if the mill is close to the starting point it's possible to engage the work before the spindle is moving fast enough. I have a broken end mill to prove it.

I'd like to read in the voltage output from the vfd (VO) and compare them to set the spindle-at-speed. When I read the VO from a multimeter, it reads 0-10V as expected. I connect it to analogin1 and read it through halmeter and it jumps back and forth between 0 and 10.1, never coming to rest anywhere.

That's as far as I've gotten but I'm sure I'll need to use near to compare them.

I'm kinda feeling my way blindly here so if someone could fill in the fuzzy areas I'd be grateful.

I found that reading through the manual for the vfd a few time's enlightens one

pd119 (default is 150) change it to 180 for near instant speed up at start of machine it can be set between 1 - 200