There is Scheme it from Digikey, a bit crude but it works.
SchemeIt | Free Online Schematic Drawing Tool | DigiKey
Al.
ok nice to know that Mach3 will stay on after an E stop
Last night I remember a thread I had on this forum back in 2009 about relays and Henrik helped me so much. This thread is here:
http://www.cnczone.com/forums/diy-cn...op_action.html
I printed all post (28 pages) and along with the schematics Henrik provided and what Al also gave me yesterday I will now make a new schematic which I will post here for comments (I’m not good at it so it may take me a couple of days)
Does anyone know a free utility to draw schematics? I found this on the net but don’t know yet how good it is
Datasheet Zone & DrawSCH : One stop to find datasheet,IC pinouts and application circuits & Draw schematics online for free!!!
Nicolas
There is Scheme it from Digikey, a bit crude but it works.
SchemeIt | Free Online Schematic Drawing Tool | DigiKey
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Much better than the one I found, thanks
Nicolas
Trying to understand the logic on the G540
The manual says that outputs 1 and 2 may be used to drive relay coils or for any other purpose and they are rated at 1A, 50VDC max. I know output 1 goes to DB25 pin 17 which is the GND and output 2 goes to DB25 pin 1 which is Output 2.
So how the G540 knows what I want to do with these outputs? Perhaps a silly question but I just can’t see it
Nicolas
I don't think pin 1 is a ground on a DB25 printer port? Look at the DB25 port pin out.
AFAIK the G540 just conditions the two outputs on the DB25 to out 1 & 2 and the outputs are triggered by whatever you have set them for in Mach output configuration.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Sorry Al but I said that output 1 goes to pin 17 which is the GND.
So the config for these two outputs is done with Mach3 which sounds good, thanks
Nicolas
Hi Nicolas ,
the E stop input to the G540 is terminal 10
in the diagram from Homann designs its the "enable switch"
linking terminal 10 to terminal 12
in post 16 ,its half of the N/C E stop switch in my diagram
in the G540 manual its labled as the "disable( E stop)" connection to
terminal 10
this E stop signal is combined with signals from the charge pump /watch dog detector circuit and current overload protection circuit
provided terminals 10 & 12 are linked and no fault is detected
an optoisolator connects printer port pin 15 to ground pins 18 to 25
Mach 3 monitors printer port pin 15 to check it is at a logic 0 (low)
John
Last edited by john-100; 05-21-2012 at 06:58 AM.
My apologies John but I never noticed your schematic in post 16. Thank you for taking the time, it is simple and easy to understand this kind of schematic.
And now I get it how Mach3 gets the input
On your schematic why you have 270 Ohms resistors on the 36V line?
And what is the thing on the bottom relay next to the 24V relay connecting the +24V and -24V lines, perhaps a diode? And why?
Nicolas
Hi Nicolas ,
the 270 ohm 1 Watt resistor is to drop 12V so a 24 V relay with a 576 ohm coil can be connected to your +36V supply to the G540
yes that is a diode connected across the third relay
it provides a path for the back emf when the E-switch opens
with out the diode the arc inside the switch will shorten its life
if you use a diode like the 1N4001 , connect the cathode marked with the white or silver band to the positive supply (use any from 1N4001 to 1N4007)
http://www.vishay.com/docs/88503/1n4001.pdf
the third relay and a low power 24V power supply is only needed if you use the low current SW-05 E-stop switch to switch the mains supply to
the 36V power supply for the G540
a 24V @ 100mA power supply will be enough to power the E-stop relay
eg POWER SUPPLY 24VDC OUT 100MA - PW2-24
to power three relays you need a 24V @ 200Ma power supply (if you don't power 2 relays from the 36V supply)
with the low power 24V supply for the e-stop relay added
you have a choice of how you power the relays controlled by the two
G540 outputs
you can power them from the 24V supply without the resistor
or the 36V supply with the resistors
check the coil resistance of your relays is about 540 to 600 ohms
John
Last edited by john-100; 05-21-2012 at 10:16 AM. Reason: add not about the diode marking
I'm not sure if this has been mentioned....
I am currently building a CNC router table as well. I am putting in a mechanical selector switch that will allow me to manually disable power to spindle controller (Hitachi X200). I still have a contactor that will be used for the estop circuit but I wanted a mechanical switch to disable the spindle when I am doing a tool change.
Although contactor failures are not that common I don't want to leave anything to chance. I wouldn't want the spindle (3hp) to start while I had a wrench on it.
Just my 2 cents...
That is always a good idea scgt40. I haven't got yet my X200 so I dont know where to connect the switch. Perhaps the X200 has a location for this switch.
Where did you connect the switch to disable the spindle?
Nicolas
There are a couple of options, If you have a Contactor that is energized when the E-stop is released you could put the switch in the contactor coil conductor.
If no contactor fitted, a couple of other options for the Hitachi, the input terminals are configurable by code, there is one called FRS Free Run Stop, code 11 and it can be made active Hi or Low as desired, it defaults N.O. = run so it would pay to change it, the other possibility is to put the switch in the feed to the FWD/REV terminals.
The latter methods do not involve shutting down the VFD.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Good options Al, thanks
I got my linear rails /screws now and started building the cnc. When the time comes for the electrical and I have the X200 I may have to revisit this thread plus I will post my schematic for comments
Nicolas
I'm drawing up the electrical drawings now. I can share them with you when complete if you want.
What I have done so far is to provide power to the X200 via a contactor (for e-stop functionality) and a mechanical switch (for L1 & L2). The mechanical switch would be used when I want to change the spindle cutter. On an industrial machine the accepted practice is to power down and lockout machine when doing anything that could put you or any body part in harms way. I know some people would argue that current technology interlocks are acceptable....I am old school....kill the power and release all stored energy.
I am slowly reading through the entire x200 manual to make sure I am fully utilizing it's features.
Hope this helps
I have changed my mind; I think it will be a good idea to finish the subject of the wiring schematic now instead of waiting for later. For reference I attach here my three relays wiring I got from the vendor
John, I will be working with your schematic from post 16 and I have these questions:
1. Why we use two power supply units? It is because the 36VDC is for the G540 and the 24VDC for the relays?
2. I don’t understand the text on the lower right corner “Line to G540 Terminal 12 -36V” etc. Can you please explain further?
3. Why there is a diode on the last relay at the bottom left and no diodes on relays 1 & 2 ?
4. One side from relay #2 goes to “Live from on/off switch and then continues down to the 24V relay and goes to “Live to 36V PSU. Don’t we mix here lines from 120VAC and 36VDC ?
5. I don’t know why Homann schematic has these IEC socket / plug and the double pole SW-06 switch. I was planning to have a single pole switch on the Black wire from the AC power going through the relay #2. Is anything wrong with this?
6. Can’t find any E-stop with two NC contacts on eBay or US. I guess I will have to order one from Homann.
After I get some answers on the above, I will complete my schematic and post it here for comments.
Nicolas
Sorry, I forgot to add my relays wiring
Nicolas
Hi Nicolas ,
as your basically following the homann design but using a 36V dc supply for the G540
using 36V relays to switch the mains power to the IEC socket and switch Aux socket would be my first choice ,
but the nearest relay available has a 24V coil , requiring a 24V supply
using a 270 ohm 1W resistor to drop the excess 12V when using the G540's 36V supply has the advantage relays 1 & 2 only can be on when the 36V supply is on
but you could connect all three relays to the +24V supply instead
I believe the G540 uses something like the 2N7000 to control the relays connected to outputs 1 & 2
http://www.fairchildsemi.com/ds/2N/2N7000.pdf
the diode shown in the 2N7000 data sheet protects the device without an external diode being connected across the relay coil
(you can still connect a diode across the coil if you want to , just ensure the cathode goes to the + supply)
the third relay at the bottom of the page is so you can use a low current stop switch like the homann SW-05 to switch the mains supply to the G540's 36V supply
it also avoids having the G540 low voltage e-stop wiring to terminal 10 and the mains supply being connected to separate halves of the same switch
to use the 24V supply for all three relays ,the negative terminals of the 36V and 24V power supplies are both connected to the G540 terminal 12
the diode across the third relay coil protects the switch contacts from the back emf when you switch off
John
PS as soon as I can i'll post a wiring diagram
PPS the double pole switch has the advantage of isolating the mains supply instead of just switching it off with a single pole switch
Last edited by john-100; 06-02-2012 at 12:40 PM. Reason: add PPs and diagrams