1 Attachment(s)
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
Sray
OK so I misunderstood what you meant when you said "If you are using a Cabinet of some kind, you would first have a disconnect (Safety Switch) at the Power entrance to the Cabinet, the Power supply from the Switch would go to a Breaker, then from the Breaker to say a DC Power supply". I have seen some cabinets with the E-stop buttons on the door so I assumed that would suffice.
Is this more what you were talking about? If not, can you show me an example?
https://static.grainger.com/rp/s/is/...ger/4B996_AS01
I read these comments on the LinuxCNC forums about setting up an E-stop with the Mesa 7i76e board.
"most estop buttons (well the ones I bought anyway) have two contacts. One is normally closed and the other is normally open.
Wire the mains power to your motors through the NC side and wire field power through the NO side. So when you push the button it cuts the mains power and lights up a Mesa input to tell Linuxcnc estop has been pressed."
"emergency stop cuts motor input power and activates the disable inputs on the stepper drivers. (Note the DC power for activating those inputs must not have its power cut though - the way those disable inputs work on stepper drivers are a bit weird, they should require activation to enable the driver instead!). You probably want to cut the AC side of the motor power supply; DC will require a much beefier relay/contactor not to arc. If you do cut the DC side, pay close attention to the DC ratings of the relay/contactor."
Here is the diagram one person posted. They admittedly messed up the NC circuit but did not fix the diagram. I made the changes to the diagram as I think it should work. Please correct me if I am wrong.
https://drive.google.com/file/d/1liu...ew?usp=sharing
Do the comments make sense and does the diagram reflect those comments correctly?
Thanks
You should not be displaying it as 110v you don't have 110v, it is 120v
Yes, that is a disconnect switch, and does not have to be door mounted, it can be mounted on the side of the Cabinet, so look for a cheaper switch that is just the switch
The diagram there would normally be a relay to switch the 120v High voltage and the EStop would only see low voltage DC 24v normally or whatever your system is using so not a very good example of how to do it. AC high-voltage and DC Low-voltage on the same EStop is not the norm, so a SSR would be best to use for that Relay if you have to switch any of the 120v Supplies
As I said you would not cut the power to the Power supply that is used for the safety circuit
The problem with switching the power off a SMPS is that it takes some time before it is off completely, by then the damage is done so it is best if the power is cut at the drives as this is instantaneous
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
mactec54
You should not be displaying it as 110v you don't have 110v, it is 120v
Yes, that is a disconnect switch, and does not have to be door mounted, it can be mounted on the side of the Cabinet, so look for a cheaper switch that is just the switch
The diagram there would normally be a relay to switch the 120v High voltage and the EStop would only see low voltage DC 24v normally or whatever your system is using so not a very good example of how to do it. AC high-voltage and DC Low-voltage on the same EStop is not the norm, so a SSR would be best to use for that Relay if you have to switch any of the 120v Supplies
As I said you would not cut the power to the Power supply that is used for the safety circuit
The problem with switching the power off a SMPS is that it takes some time before it is off completely, by then the damage is done so it is best if the power is cut at the drives as this is instantaneous
I understand now that E-stops are for low voltage circuits and the disconnect is for the high voltage circuit. I see there are magnetic switches that help protect from power outages that once tripped the power is shut off until the switch is manually turned back on. Can I use one of these switches for the disconnect switch? Or do I need to add that in separately somewhere?
Thanks
Re: Need some guidance on which wire I need to use.
By magnetic switch, I assume you mean a relay?
This is the normal way to set up a E-Stop string, all the devices that detect an emergency, including the E-Stop P.B. are 'N-and'ed together (in series), so in the case of one of them opening the circuit, the E-Stop relay drops out and indicates an emergency via the relays contacts .
The NFPA79 I posted shows such a string in the schematic example.
N/C Contacts on the E-Stop relay open the motor supply's circuits for example..
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
Al_The_Man
By magnetic switch, I assume you mean a relay?
This is the normal way to set up a E-Stop string, all the devices that detect an emergency, including the E-Stop P.B. are 'N-and'ed together (in series), so in the case of one of them opening the circuit, the E-Stop relay drops out and indicates an emergency via the relays contacts .
The NFPA79 I posted shows such a string in the schematic example.
N/C Contacts on the E-Stop relay open the motor supply's circuits for example..
I apologize for my troubles understanding these stops/switches. I do tons of research only to walk away completely confused because I either read contradicting info or I completely misunderstand what I learned.
Here is an example of where I found this specific info about the magnetic switch I mentioned, look at this snippit taken from the PrintNC wiki site. It explains the difference between a (Latching) Safety Switch and a E-stop.
https://drive.google.com/file/d/1nBv...ew?usp=sharing
The snippit was taken from https://wiki.printnc.info/en/electro...-off-emergency
This second link is a copy of the PrintNC electrical diagram showing where/how the two are connected. You will notice that the images they use of each component in the first link were clipped from their diagram in this link.
https://drive.google.com/file/d/1z21...ew?usp=sharing
Based on what I read on their site and the diagram, the (Latching) Safety Switch sounds very much like the Disconnect Switch that was brought up earlier in this thread. Based on the diagram it looks like it is on the high voltage side which is what the Disconnect Switch is used for. It even says that it can be used as the Master Power On/Off switch.
Once again, sorry for my ignorance.
1 Attachment(s)
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
Sray
I understand now that E-stops are for low voltage circuits and the disconnect is for the high voltage circuit. I see there are magnetic switches that help protect from power outages that once tripped the power is shut off until the switch is manually turned back on. Can I use one of these switches for the disconnect switch? Or do I need to add that in separately somewhere?
Thanks
As AI has posted, is how it is normally required, in your case you don't need a Magnetic Contactor for your low 120v AC system, a simple SSR (solid state Relay) is all you need this will do the same as a Contactor
You would add the SSR in the EStop circuit just as you would a Contactor to switch the 120v AC Power.
No, you can't use a contactor as / for your cabinet disconnect
The disconnect is only to turn the Power 0N /0FF to your cabinet / Machine, in your case it can be just a simple switch Like Snip
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
Sray
I apologize for my troubles understanding these stops/switches. I do tons of research only to walk away completely confused because I either read contradicting info or I completely misunderstand what I learned.
Here is an example of where I found this specific info about the magnetic switch I mentioned, look at this snippit taken from the PrintNC wiki site. It explains the difference between a (Latching) Safety Switch and a E-stop.
https://drive.google.com/file/d/1nBv...ew?usp=sharing
The snippit was taken from
https://wiki.printnc.info/en/electro...-off-emergency
This second link is a copy of the PrintNC electrical diagram showing where/how the two are connected. You will notice that the images they use of each component in the first link were clipped from their diagram in this link.
https://drive.google.com/file/d/1z21...ew?usp=sharing
Based on what I read on their site and the diagram, the (Latching) Safety Switch sounds very much like the Disconnect Switch that was brought up earlier in this thread. Based on the diagram it looks like it is on the high voltage side which is what the Disconnect Switch is used for. It even says that it can be used as the Master Power On/Off switch.
Once again, sorry for my ignorance.
You are looking at machines that have a lot more going on than you have, so this is where it can be confusing for you.
Your system is very simple, you have 2 Power supplies some Stepper Drives a Breakout Board and this is about it so don't complicate things for yourself.
A Disconnect Switch is just to turn the Mains 120v supply in your case 0N / 0FF at the cabinet, this has nothing to do with having a safety EStop Circuit
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
dazp1976
Cabinet disconnect is what we are referring too, that is a strange switch to be using for a wall mounted disconnect.
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
dazp1976
For what kit I've got it was a cheap option to kill/isolate the cabinet. Not worth the hassle putting a round kill/lock type switch on the box.
Still messing with my E-stop circuit tbf. I haven't been able to touch the MC in 6 months.
Turns out a 24vdc contact is too slow acting for use as a spindle cut-off. So now going to try my E-stop button on mains V through a 220v magnetic contactor coil A1/A2, 3 terminal NO.
T1 servo main power + 220vac
T2 servo main power - 220vac
T3 control stop circuit (low side) 24vdc
Could end up 50/50 with a noise issue like this. If so I'll have to use a SSR to trigger the control circuit instead.
The Servo itself would throw a Fault signal anyway but if that failed, the SSR is there doing the job too.
Can't justify the £300 price tag for a safety relay!.
You normally would not switch the Neutral, the Hot / Live in your case would be all you switch when using Single Phase supply
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
dazp1976
Thanks for the feedback. That gives me another idea then that will save getting another contactor for steppers.
T1 Servo main power + 220vac
T2 Stepper drivers psu + 220vac
T3 Control stop circuit (low side) 24vdc
If your 24v DC is powering the Brain of the machine you don't cut power to that, High voltage AC and 24vDC switching on the same contactor is not a good idea, some contactors have Auxiliary Contacts on the side that could be used for switching the 24v DC
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
mactec54
You would add the SSR in the EStop circuit just as you would a Contactor to switch the 120v AC Power.
I am interested in this design for my E-stop Safety Circuit. I am new to SSR's. Can someone help determine which SSR I would need for my system and help explain how it would be hooked up?
NOTE: I would like to be able to send a signal to LinuxCNC when the E-stop circuit is triggered.
Some questions I have:
- Would I need a DC to AC relay?
- Would I run low voltage through the NC of the E-stop and then run the 120VDC main line for the large PSU through the NO side of the E-stop?
- If the answer to the previous question is yes, where does the low voltage come from and go to? Mesa board (NC, I/O)? Driver EN+/EN-? 24V PSU?
Is this close to what I would use?
https://smile.amazon.com/TWTADE-SSR-...%2C183&sr=8-50
Here are my electrical components if this helps.
1. Mesa - 7I76E STEP/IO Step & dir plus I/O daughtercard
2. SMPS 60V1200W switching power supply 60V20A DC power transformer AC220V / 110V to DC60V1500W Electric machine power supply
3. MEAN WELL MDR-60-24 DIN-Rail Power Supply 24V 2.5 Amp 60W
4. DM860T Digital Stepper Motor Driver 2.4-7.2A 18-80VAC or 36-110VDC Stepper Motor Controller for CNC
Shawn
Re: Need some guidance on which wire I need to use.
Now that I read through my post above I think I am confused on how the circuit(s) would run through the E-stop switch. Hmmm
Re: Need some guidance on which wire I need to use.
Quote:
Originally Posted by
dazp1976
Ahhhh. Nevermind about a second magnetic contactor.
Just realised I have some ice-cube power relays.
I can tie them in series to the A1/A2 Estop button line of contactor #1 and they can then be used to trigger the I10 reset fault.
So 220vac+ > 3A fuse > A1/A2 magnetic > A1/A2 ice cube > Estop button > 220vac-
Magnetic #1 T contacts as above.
Ice cube - I10 control board reset/stop fault.
All this agro because a 24vdc contact unit is just too slow acting. Annoying.
You sure it is the 24v contact acting slow, or just the normal thing that happens when you turn off a SMPS these power supplies can take some time to drain the power from the circuits, and may appear that the switching relay is not doing its job
You should start your own Thread if you need to post more about your system
