Best way to e-stop spindle and VFD?

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Martin,

@MVall

If I can figure this out, then it could also be wired in series with a physical estop button to the same pin23?

yes, as explained above:

@Aiph5u

if you want to connect both, i.e. you already connected a ‘normally closed’ emergency switch, you will have to wire the switch and the relay contact in series. If you use ‘normally open’ for both, you would have to wire them in parallel (and set “estop” setting in the I/O Configuration Tab to “normally open”).

@MVall

And the relay contact outputs are for higher voltage and current.

yes, but

1. only to what it’s rated, not more (see excerpt of manual shown above), and also
2. only if the load fulfils the needs of a solid-state relay, i.e. a load that constantly draws the required minimum load current when on.

As the specified maximum currents for the AL{0..2} terminals are not that high (a professional dust extraction system would draw much more current), their use is somewhat limited. That’s why I said above:

@Aiph5u

You can however use the outputs 11 and 12 for relays as strong as you want, als long as you provide an appropriate driver circuit in front of the control coil.

And just in case you should run out of outputs, you could also wire an external relay to a relay output, as long as the external relay’s control input meets the requirements 1 and 2 above.

@MVall

So on the relay contacts, I see that some people are using the multi-output (normally open I believe) on their Chinese VFD to trigger this Digital Loggers IoT relay (IoT Relay Frequently Asked Questions - FAQs), which is more plug-and-play for those of us who are not too electronically savvy.

Yes, if you are not an electrician or an electrical engineer, you have to use things that you can easily plug together. But that does not mean that it cannot be dangerous! With electricity, you always need to acquire some knowledge since it can be harmful, at least to your hardware (if not to your house and your body)

I don’t know the Internet-of-Things relay you linked to. You have to look at the spefications, always, of what you connect on one side and of what you connect on the other side. So keep in mind that on the Hitachi aka Omron, the relay output has a maximum and a minimum current because it’s a solid state relay.

@MVall

Even though the relay contact on the Hitachi seems similar to the multi-output on the Chinese VFD , I’m not sure if it could function in the same way.

The “Multi-Outputs” DRV and UPF / DCM on Huanyang HY Series are open collector outputs. The KA/KB and FC/FA outputs seem to be internal relay outputs. But the manual of such cheap chinese manuals is poor. But I have seen on photos that they have at least one electromagnetic relay on the pcb. So the limitations of a solid-state relay (their minimum load current, and their risk of being destroyed more easily by excessive currents or voltages) would not apply there, but certainly they do with the Hitachi/Omron AL outputs.

@MVall

However, they also tie in to internal 24v power on the VFD

Again, before you connect something to an internal 24 V source of a VFD, be sure that the current that the electromagnetic relay coil or the solid-state-relay input that you wish to connect only draws less than the maximum current of this output (and be aware that it could also be in use by other additional functions). The maximum current of a power source should always be found/be looked for/be looked up in the datasheet or manual. If you connect things, you are always responsible for having read the specifications in order to make sure your things don’t vaporize .

By the way, if you start studying datasheets you will learn a lot. And if some hardware lacks useful datasheet, better not use it.

@MVall

So a basic summary of what I’d like to potentially do:

1. open collector output terminal 12 on VFD set to trigger on trip or power loss, wired in series to controller pin 23.

If you have an open collector output, this means that a part of the circuit is missing, and you have the opportunity (and the necessity) to provide this missing part. This is usually done with a pullup resistor and a power source, and of course the load. But since the pin 23 “estop” of Onefinity Controller is programmed inside the AVR microcontroller as an input with internal pullup resistor (AVR’s feature this), you could wire Hitachi’s/Omron’s pin 11 or 12 to pin 23 “estop” on Onefinity Controller, and “CM2” to pin 25 “ground”. But I would rather use the small signal relay solution I described above because it gives you galvanic isolation and you don’t have to worry about ground. The wiring would be as explained in the picture above: Terminal 11 or 12 wired to the control coil of a small signal relay like Omron G5V-1 24 V, the other coil pin supplied by a 24 V power supply which in turn has its ground connected to CM2, not forgetting the flyback diode backwards over the relay coil. And then on the other, galvanically isolated side of relay (not shown in picture above) wiring the relay contacts to pins 23 (estop) and 25 (ground) of the CNC Controller.

@MVall

2. possibly relay contact output (normally open) set to trigger on run command and wired to Digital Loggers IoT relay. This would be for spindle water pump and enclosure fans.

I had a quick look at the IoT relay WWW link you provided:

Q: How much current does it take to trigger the control port?
A: About 0.2mA, the input is constant current. 12-120VAC or 3.3-48VDC will trigger the relay. DC trigger input is polarity sensitive. Pay attention to the positive(+) and negative(-) markings above the trigger connector.

– Source: digital-loggers.com: IoT Relay II FAQs

So it says it sucks 0.2 mA constant current on the control input. Whether this is enough for the requirements of the solid state relay behind the Hitachi’s AL{0..2} relay outputs, you already can tell yourself now with the information I gave you above. See the specification of the AL{0..2} outputs of Hitachi VFD above. It’s not said for 24 V DC explicitly but is says “5 V DC, 100 mA” minimum, and 100 mA with DC is usually what you need at last as a rule of thumb for a load with a solid state relay.

However if you were forced to use this AL relay output of the Hitachi VFD because the other outputs are already in use, you could of course wire a driver in front of the IoT relay input that ensures consuming 100 mA. But then again you would be wiring electronics then, not just plugging things in.

But, you still have the other output, “11/EDM”. If you don’t use extended device monitoring (EDM), output 11 is free to connect any relay on it. And if you do use EDM, you don’t need to call “estop” on the CNC Controller, since the EDM would take care of it, so output 12 would be free then.