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FM50 VFD Jog Speed Incorrect

FrankW

Plastic
Joined
Mar 18, 2007
Location
Johns Island
I have a TECO FM50 VFD (FM50-201-OC) installed to operate the motor of my South Bend 10L Lathe.

The problem I have is the Jog function does not operate the VFD at the Jog Speed 20 Hz programmed in F_9?

When activated, the Jog Button operates the motor at 30 Hz, not 20 Hz? (30 Hz is the lower frequency limit.)

Do I have a programming or wiring problem? Or is this the expected behavior of the FM50?

The Jog frequency is set in F_9 = 20. The lower motor speed limit is set in F_7 = 30
The Jog button is a normally open switch when closed sends 12 VDC to position #6 SP1 on the VFD.
SP1 is programmed in F_19 = 1 for the Jog function. When closed, the Jog Button also sends 12 VDC to VFD Position #3 Forward, which is the direction to jog.

I also set the SP1 frequency in F_8 = 20.

Any help is appreciated,

Frank
 
I think the lower limit value is absolute for that drive. That is, the motor will
*not* run below that, no matter what.

Suggest you reset the lower limt to 20 termporarilly and see if the jog works
correctly then.
 
I think the lower limit value is absolute for that drive. That is, the motor will
*not* run below that, no matter what.

Suggest you reset the lower limt to 20 termporarilly and see if the jog works
correctly then.

Bingo... The lower limit function is an absolute, it overrides everything else. It's there in case you have a risk of damage if run slower.
 
Thanks for the responses!

I reset the lower limit to 20 Hz and the Jog function now jogs at 20 Hz.

I think I will keep the lower limit at 30 Hz and just live with the Jog function at 30 Hz.

It is nice to know this is a software limit and not a wiring or programming error on my part.

Frank
 








 
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