Control extraction via saw’s VFD?

[LJM]

I know that the VFD running my table saw will not run two motors. However, might there be a way that I can use it to turn on my 240v extractor when I switch on the saw, perhaps using a relay?

Thanks in anticipation of a clear, concise and authoritative answer… ;-)

 

[RichardG]

It depends on the VFD, the one I use does have an internal relay that can be programmed to close on one of 15 or so conditions so it would do this, do you have a full manual for your VFD?

 

[LJM]

Yes, the VFD is a Siemens V20, which comes with a good manual. I’m trying to work through it to find anything relevant

 

[Sandyn]

That's the same one I have on my drill. A quick look at the manual shows it does have a relay output, You know how versatile the VFD, but it takes a while to figure out how to use all the parameters. Look at P0732, P0732, P0747 and P0748. One test I would do is check continuity of the relay which are D0 2 NO, D0 2 C and D0 2 NC. These are at user terminals 17, 18 and 19. (3 terminals at the right hand end of the user terminals, above the earth symbol)
I just checked my one and the relay doesn't operate by default, but there might be a way pf programming it's function and you could use that, to drive another higher rated relay for the extractor. . I will also have a look through the manual to see how it might be possible, but I'm out all day tomorrow.

 

[Sandyn]

Had time to have another quick look. I think there is a possibility using the Holding brake function, parameter P1215

 

[LJM]

Excellent, thank you! I’ll look into it… if I can get this working, the next step will be to set up the other machines in the same way

 

[Sandyn]

Any progress? I tried setting the holding brake function. I can hear the motor operation different, but the relay didn't operate. I didn't check the open collector output D01. I will have a bit more time to look later this week.

 

[LJM]

Any progress? I tried setting the holding brake function. I can hear the motor operation different, but the relay didn't operate. I didn't check the open collector output D01. I will have a bit more time to look later this week.

Thanks for the feedback! I haven’t yet progressed this in practice because I’ve not yet collected the saw that the VFD is going on. I’ve a long train journey today, so will have time to progress it theoretically.