VFD Code

Do people typically code fwd/rev interlocking for VFDs?

I vaguely remember reading somewhere that if both the forward and reverse signal were applied to a Toshiba (G7) drive, the drive would run reverse.

We're now onto Mitsubishi A700 drives.

In my current application, if the operator was to attempt to jog both directions simultaneously, there would be no consequence.

Although it is very simple, I'm just thinking that the cleaner the code the better.

Dan.

we interlock our code, even if some say its not necessary.

when we stop a drive, we have a spin down timer.
even if you hit reverse, the spin down timer must run first.

safer, less chance of problems, lesser chance of burning up the drive.

regards,
james

Thanks James,

I just read in the manual that if both signals are applied, the drive decelerates to a stop.

That still leaves the anti-plugging, or spin down consideration.

Since the drives are all set to decel to stop (rather than coast), I wonder if the signal to change direction is not valid during decel.

Dan.

I just read in the manual that if both signals are applied, the drive decelerates to a stop.

Click to expand...

Every drive I've ever worked with acts this way.

That still leaves the anti-plugging, or spin down consideration.

Since the drives are all set to decel to stop (rather than coast), I wonder if the signal to change direction is not valid during decel.

Click to expand...

Again, every drive I've ever worked with, when set to decel to a stop, allows an immediate or delayed switch to direction input. For example, whether you turn off fwd and turn on rrev immediately, or wait until it's ramping down, the drive doesn't really care. It ramps down decel towards stop, and once at 0, then accels from 0 to set speed on accel ramp.

If it's a concern, or the drive is set to coast to a stop, enable the function for starting into a spinning motor.