Power down when finished??

[CarbonKevin]

Hi all,

I'm running Mach3 into a SmoothStepper into a G540. My router is a Bosch Colt.

I want to have the machine turn itself off completely off after it's finished running a program.

I have designed a relay setup that will take care of turning the router and dust cleanup vacuum on and off at the right times. No questions or problems there.

I also want to be able to turn off power to the G540 and the hold down vacuum when the job is finished - I don't like the idea of the steppers and G540 sitting idle, generating heat, for any more time than necessary. Once the job is done, I don't need the vacuum hold down, either.

Problem is, I need to be able to power up the G540 and hold down vacuum before I've loaded Mach3 - potentially before the computer is even turned on, in the case of the hold down vacuum - but I want to be able to shut both items down with a signal once the job is finished.

I'm envisioning a momentary switch that powers up some sort of relay network that stays on either until it recieves a signal from the G540, or until a neighboring circuit (the power for the router, for example) loses power.

Any ideas? Thanks!

CK

[brtech]

Sure. You use a relay with an extra pole as a latch, and use another one controlled by Mach to break the latch.

You need two relays and a separate power source (like a little 5V wall wart).

One relay is the one that powers the gecko and the pump. It needs an extra 'pole'. Call this the "power" relay.

The other is a relay controlled by Mach3 (from a control line on the gecko). Call this the "control" relay.


Connect one side of the power relay coil to the separate power supply +.
Connect the other side of the power relay coil to the NC connection of the control relay.
Connect the common connection of the control relay to the NO connection of the momentary switch AND the NO connection of the extra pole of the power relay.
Connect the common connection of the momentary switch to ground.
Connect the common connection of the extra pole of the power relay to ground.
Connect the - of the extra power supply to ground


When everything is off, both relays are off.
When you depress the momentary switch, the coil of the power relay is energized (one side is connected to + of the extra supply, the other is connected to ground through the NC connection of the control relay, through the switch).
The relay activates, and now the extra pole also connects the coil of the power relay to ground. At this point, the switch can be released, the extra pole is holding the coil energized. This is the latch.

When Mach3 turns on the control relay, the NC connection through the control relay is broken. The power relay turns off, powering off the gecko and the pump.

Mach3 then turns off the control relay. The power relay is not activated, because neither the momentary switch nor the extra pole is on.

[CarbonKevin]

Maybe I've read your reply wrong, but I'm understanding that when Mach3 goes to turn on the spindle at the beginning of the program, the NC is broken and then the Gecko and pump would lose power? What would that accomplish?

I like the way you're thinking, though...there has to be a way of doing this.

I'd like to avoid using a second control signal - I'm not an expert at GCode by far, but from what I see, the only constant in every program of mine is a command to turn on the spindle (M3) and at the end M30 to shut it all down. I could use the coolant on code (M7), but I haven't seen it in any of my programs, so I'd have to manually insert it each time - not an ideal solution!

[brtech]

This doesn't interact with the router power - you said you had that taken care of. You have to power down the router before you power off the gecko, but so what. The power relay would only power the gecko and your vacuum pump.

You can't control things with magic - you need a control signal, and you need to invoke the thing some how.

I'm not a Mach expert, but there may be a way to execute some code on every program exit. I'm not entirely sure that's what you want to do.
Rather, again, not knowing how to do this, but it's possible to create a button in Mach3 on the screen that can turned on and off. If you can execute some code at the end of every program, that code could test the screen button state, and power off if it's set. That might make it work - it wouldn't power off unless you hit that screen button.

Brian

[CarbonKevin]

Sorry for the misinterpretation, Brian! Lack of sleep makes me really bad at figuring out technical writing.

So far, I've found two options for achieving this control layout: (this is counting the router power, btw)

A momentary switch, a wall adapter, two single pole relays and a double.

or

A momentary switch, one single pole and one double pole WITH an extra control signal.

It might be possible to do much better, though. I'm working up a schematic that will use the momentary switch, the wall adapter, two double-pole relays, or possibly even one single and one double - and with only the router control signal.

But it's going to be a voodoo design...think multiple pathways to power the adapter, and/or using the common, NC, and NO legs on each relay pole for two DIFFERENT functions each. And I'm going to try and do it without diodes or anything else.

The difficulty right now is timing...while switching between NC and NO states in a relay, there is a millisecond that neither circuit is complete, and that would be a very bad thing while a program is trying to run.

I will post my results after I've figured out and tested them.

Here's hoping I don't create a paradox that destroys the planet...2012 AD would be pissed if I went and did it's job for it

[brtech]

I think router power should be completely independent of the gecko and pump power. That should only be a single pole relay, from one control output. You really want to be able to turn on and off the router power while the rest of the system is up and running.

You wanted away to effectively sleep the entire system. That takes something like what I described, and it doesn't depend on relay switching time. I think you need a completely separate control for that, completely independently of the router control.

Count the states:
Frame and pump running, no router
Frame, pump and router running
Nothing running

While there are only 3 states, you need two bits to control 3 states. You can't do it with one. There is no way to indicate router power off without gecko and pump off, which I think you need.

Please remember then when the gecko power shuts off, all control signals connected to it float.

[CarbonKevin]

The activate pulse for the router should be independant. I agree there.

You're also right about there being 3 states, and the need for 2 bits.

There are already two bits, though. First bit is controlled by the pushbutton switch, second bit comes from the gecko as the router on command.

The trick is that bit 1 on activates state 1, but bit 2 on activates state 2 AND bit 2 off deactivates everything.

You've essentially made a latching relay with the wall wart transformer - I might wind up using an actual latching-type relay in it's place, to simplify things a tad.

As for my timing comment earlier, what I was referring to was the problem that most DT relays are "break before make" - the NC connection breaks before the NO contact forms. The relay type that we want are called Type D - which make the new contact before breaking the old one.

So again, I think this is possible. You probably still disagree...so the only way to resolve this would be for me to either come up with a working circuit, or fail at it. Then we know!

[brtech]

Well, it's your machine and your design, but I would want to be able to turn my router off without powering down the entire system.

Latching relays are helpful, but tend to be expensive. You could line power a latching relay coil on, but you need to use low voltage DC to power it off. Latching relays don't come that way. That would mean another relay to allow Mach control, or the wall wart and a low voltage DC latching relay.

In my design, there is no problem with break before make, but I'm not sure what you are planning.

Have fun!

[Al_The_Man]

Brtech sounds like he has covered most bases, it sounds on the surface you are trying not only to do a few things out of the norm but may be against code etc, although for a privately owned machine you can do just about anything you want.
If you want some thing that can be left powered at all times and look after programmable logic, you could look at a Smart Relay,
http://www.alliedelec.com/Images/Pro...ol_8140258.pdf
These are made by a few manufacturers and essentially are the same unit, relabelled.
They do not need offline programming s/w etc and can be picked up on ebay fairly cheap.
Some even include a real time clock.
Al.

[CarbonKevin]

Originally Posted by brtech Well, it's your machine and your design, but I would want to be able to turn my router off without powering down the entire system. Latching relays are helpful, but tend to be expensive. You could line power a latching relay coil on, but you need to use low voltage DC to power it off. Latching relays don't come that way. That would mean another relay to allow Mach control, or the wall wart and a low voltage DC latching relay. In my design, there is no problem with break before make, but I'm not sure what you are planning. Have fun!

Brian,

I'm a bloody nimrod! The switching arrangement I described is all well and good...UNTIL you have to shut off the router for a tool change, clean out the chip vac, or whatever. In which case, the whole thing would shut down.

So I'm gonna go sit in the corner with my dunce cap for the next few minutes.

I'll be designing this system around two output signals, hopefully Mach3 has some simple way of ensuring both signals happen at program start, and stop when the program's over. Thanks so much for all your help, I really do appreciate it!

Originally Posted by Al_The_Man Brtech sounds like he has covered most bases, it sounds on the surface you are trying not only to do a few things out of the norm but may be against code etc, although for a privately owned machine you can do just about anything you want. If you want some thing that can be left powered at all times and look after programmable logic, you could look at a Smart Relay, http://www.alliedelec.com/Images/Pro...ol_8140258.pdf These are made by a few manufacturers and essentially are the same unit, relabelled. They do not need offline programming s/w etc and can be picked up on ebay fairly cheap. Some even include a real time clock. Al.

Hey Al

Put it down to the unnatural joy I get from solving difficult problems. Sometimes it leads me to overcomplicate things. And yet - I look at the Smart Relay, and I say to myself "that looks far too complicated".

So...are you in MB, SK, or western ON?

[Al_The_Man]

Originally Posted by CarbonKevin Hey Al So...are you in MB, SK, or western ON?

Your neighbourhood.
Al.

[Pandinus]

Are you aware that the G540 has a charge pump circuit for safety purposes (and really it should be used) so if MACH or EMC etc. are not running the G540 and all outputs are disabled... also when the charge pump signal is absent the motors receive no power and can be freewheeled...

Unless of course you override the charge pump... and then while you are changing a router bit while the computer is turned off and someone turns it on, or the PC crashes and reboots, or the power fluctuates because of a storm somewhere or something else happens... the port goes into flux and fires up your router removing something I'm sure you'd rather keep... It is probably best practice to switch off your router and unplug it prior to changing bits... but I know that theory flies out the window when its not spinning already... why switch off something that is already off??? I have worked in a plant where the power goes out, and people don't think to turn off their equipment before the power comes back on... table saws left on with the blade up etc... anywhere you can, design for safety BEFORE convenience.