Spare M codes

[bd41612]

Can any of you point me in the right direction to use the spare M codes?  I have never done this before.  I want to use a spare M code (M170-M179), but I don't know how / where to look for the finish signal and how to utilize it in the program.  Can any of you guys help me out?

[cncworker]

I've used spare M codes on our Haas VMC and put those into the program.  But without any more info on what you are trying to do, we can't be much help. 

What are you trying to accomplish?

[bd41612]

Looking to wire in a switch to confirm a proper work piece load that can be read in the program to decide whether or not run.  Easy with a probe, but I don't control the wallet.

[Bob W.]

Spare M-codes are relay switches that are controlled by M-codes.  Usually there is an m-code to turn the relay on and one to turn it off.  On my Makinos the first spare relay is turned on by M581 and off by M580.  It is really that simple, you are just turning a relay on and off with an m-code.  What you need to do is find the bank of relays, then determine which is activated by the m-codes.  It sounds like you would want to wire the relay into the e-stop or feed hold loop so if the m-code is activated and the micro switch isn't engaged it will alarm the machine.

[specv]

M codes can also call a sub program as well, on Fanuc and Haas controls. But it looks like Bob W. has what you are looking for. 

[bd41612]

Thanks Bob, that's a step in the right direction.  The other way would be to use an open I/O connection, but I'm not sure how to read the status of it.  BTW, nice pictures, I like what you're doing with your shop.

[taperlength]

The finish signal just allows the program to continue past the M code that required it.  For example on a lathe, when the chuck open M code is read, the program waits for the finish signal from the sensor on the draw bar to close.  If it does not get the signal, the program just halts there.

[Bob W.]

The finish signal just allows the program to continue past the M code that required it.  For example on a lathe, when the chuck open M code is read, the program waits for the finish signal from the sensor on the draw bar to close.  If it does not get the signal, the program just halts there.

I have always wondered about a feedback signal like this.  Any idea how to wire this in or implement it?  I have always used the e-stop or feed hold because it is the simplest to implement but a finish signal would be better in certain applications.

[Zoober]

Funny this came up.

We have many Star Swiss machines with LNS barfeeders.

I have been tasked to improve our Swiss setup reduction and efficiencies. I found out this week that when the machines receive an end of bar signal, the star uses an M0 to fire the barfeeder.

Yes. An M0.

So if we are on the last part of the bar, regardless of where we are in the program, if we have an M0 (for chip removal, check, or manual part extraction) the barfeeder cycles, loading a new bar.

When I was an apps guy for Miyano, we used a dedicated M20 for the barfeeder.

I spoke to LNS and Star, and they both said use an M1.

Really? You remove an industry standard Mcode to fire a barfeed?

The reality is, you hook up a normally open relay to a Mcode. You fire the Mcode, closing the relay,which in turn sends a 24vdc signal to the barfeeder (or other aux device). The device sends back a confirmation signal to the machine to open the relay as a Release to continue operation. The ladder or relay logic dictates that the machine can only operate in an open relay condition.

To my dismay, I had to explain this to the Star guy when I requested use of something other than a M0. He said "we can probably do that for the Fanuc machines, but definately not the Siemens machines". We will be escalating this, as we have 13 Stars. They will not get off on ignorance and laziness.

Between myself and our maintenance guy, this is very doable. But if we have to pay for the optional Mcode, we will make them implement it. If nothing else, just because of principle.

[CAM-mando]

Zoober that's crazy. Our sister company does strictly medical. They have about a million stars with LNS feeders. I'll ask our maintenance guy on Monday about it.

 

My only experience with the "spare" m codes is for firing external 4th axis indexers. As Zoober explained the control sends a signal and waits for a signal back. In the case of the indexer it performs it's next preprogrammed action then sends a return signal to the control allowing it to continue. In the case if the indexer you can also send a "release" signal to the control before completing the next programmed action. An example would be for simultaneous milling in A and X to mill a helix. This requires correct timing to work.

 

The machine builder decides what unused m codes are made available so you'd have to check the machine manuals. We always had our 3rd party machine service guys come in and hook them up. As far as I know they just tap into an existing terminal block with a 2 conductor cable usually with a mil spec type connector that plugs into the external device.

 

If you do happen to be doing this for an external indexer, another option may be the RS232 using macro b d print statements.

 

I'd say if you can't find it in your machine manual wiring diagrams talk to your service guys.

[Zoober]

Please let me know what your maint. guy says, CAM.

We have SB16's SR20RII's and SR20J's with Fanuc, and ECAS 20T's with Siemens.

[CAM-mando]

Zoob I sent you a PM.

[Zoober]

Thank you sir!