VFD/ESS configuration conflict

I was hoping to re-define the Delta VFD relay output from reporting a Spindle Error to Spindle Stopped. Because I have a ACT I’m trying to set my system so I can’t eject the tool holder while it’s still spinning also before doing a tool change.

The VFD part is easy but I ran into several problems. First according to the ESS configuration Pin P2-14 is an output and is called Spindle On. I think it goes out on the breakout board on pin 41. Pin 41 (white wire) goes to pin RA (normally open) on the VFDs relay. Pin 42 (blue wire)

is 12V and goes to RC (relay common) on the VFD.

According to the VFD manual the relay is also an output and allows the VFD to output a configured status of the unit back to the ESS.

So if I’m not wrong putting two outputs together is in the book of bad. If I am wrong please let me know.

I disconnected the wires from the Spindle Start pins and everything seemed to work normally so I hope I can ignore it.

Use a separate and dedicated relay for the drawbar. You want full control of that process. I would also advise against using the two relays on the ESS/AvidCNC breakout unless you also change the configuration for mist/flood/vacuum that was used on the output signal in the ESS configuration. Should you mistakenly use the wrong post processor you could drop the tool when it kicks on one of those functions (been there, done that, the t-shirt was blank on both sides :thinking: ). I think the default for relay #1 is Flood and #2 is vacuum.

Remember the stall is an error event. It will only be generated AFTER the stall has occurred. Ejecting the tool will be after the damage has been done.

Personally, I would not mess with any of the spindle setup. If it fails to report spindle error the machine will continue to execute the running program and may cause more damage.

The CNC Depot provided spindle controller comes with a with a dedicated drawbar relay. I currently have the relay controlled by a footswitch and a button at the spindle to handle manual tool changes.

Using the VFD relay to sense zero rpm does two things. When the spindle is stopped it enables the drawbar relay and when running automatically turns on the purge air to the spindle. It may also enable the dust collector and coolant depending on the currently running G-Code. Watch an excellent video on Clought42 that covers this topic and much more. ATC Spindle Part 10: ATC Interlock and E-STOP wiring [REUPLOAD] - YouTube

I’ve also installed a pressure switch to make sure there is sufficient air pressure for the drawbar to operate and provide purge air. Trying to do a tool change without it can make for a very bad day. This error will not allow the machine operate.

If indeed the VFD’s spindle relay output is tied to the ESS’s spindle on output instead of a ESS input the ESS has no way to see let alone respond to a spindle error. I’m hoping to use the CAN bus to monitor errors. Although not real time I’d rather lose a tool or part or the whole machine compared to having an end mill and ISO30 tool holder flying around the shop at 18000 rpm. Machine tools are dangerous. S*#^ happens. I once watched a guy saw his thumb off with a band saw. Something I’d rather not see again.

If that VFD is like the Hitachi (or any other VFD I’ve seen), it uses MODBUS instead of CANbus. I’m controlling my WJ200 using modbus and a USB modbus dongle, so I have access to more status and control than the wiring allows. I’ll probably use the wiring to do hard overrides (disable drawbar relay when spindle is running sounds like a useful one ;).

Note, however, I’m using linuxcnc and not mach3, so I don’t know how to use modbus with mach3.

1 Like

Thanks for the info. It may be awhile before I get to that point. There is a lot of hardware to build and software to write before that. Right now I’m building the movable gantry to hold all the tools. Good to know someone out there understands that part as I will probably need your help. Thanks again.

Thar be dragons! :dragon:

Check with Alex at CNCDepot.net. They have removed that documentation from their site.

Sorry my explanation was that great. The VFD relay I was talking about isn’t used of the drawbar. There a small programmable relay that can be used in a bunch of different ways. Default setting is used to report errors like over or under current and others. It can also be configured to indicate that the spindle is at zero rpm which is how I plan on using it. Like most relays it has a common connector (RC) and a NO (RA) and NC (RB) connectors.

Hope that clears things up.

Not sure what CNCDepot removed. The UTube video Jim posted is still there. I watched it yesterday. Sent an email to them today. Thanks for the help.

Oh, sorry. Here is the link to the documentation for installing your CNCDepot S30;


The document that is referenced in that video is no longer available.

Please call or email CNCDepot for direction. Like the YouTube guy, I am not the source you should be referencing for CNCDepot S30 technical information :slight_smile:

Sorry for my confusion. It turns out the Avid documentation is a bit confusing. As far as I know there is only one relay in the VFD and it’s used to send status information back to the ESS. Avid shows a “Spindle Relay” as an output on ESS P2-14 which is the confusing part. Turns out the ESS P2-13 is the real input for the VFD relay and is called PTC, whatever that is.

Maybe it’s just me being an engineer. I’m used to seeing a certain type of documentation for systems like this. I believe what’s needed are real schematics which would have to already exist. They just need to be made available. Avid has OK schematics for the spindle controller side but not so great for the rest of the system IMHO.

The way I figured it out was after changing the VFD 03.00 config to 19 but just before loading the software to handle the new input I started getting PTC errors. So until my ATC system is fully ready for testing I set the VFD back to its default configuration.

I totally blew this one and I don’t mind admitting it.

Double check it but I believe PTC is the thermal protection for the spindle.

The guy in the video built his own system so he could define it any way he liked. He might have even been the author of said doc!

Personally, I have discovered that AvidCNC is boringly standard in these things. So they tend to keep with accepted norms and don’t try to be unique just to be “different.”

Which isn’t a bad thing in my book.