M21 question

Ok guys, here is a likely simple question.

Problem:
I have a fixture to hold 8 parts that are just saw cut on both ends which are then machined clean.
The fixture holds the parts front to back, but I cannot use a fixed stop on the side as it would be mowed off by the endmill.
So, I've made up a removable block with setscrews to align the part, clamp and then remove the block.

Well, you've guessed it, the guy ( henceforth be called Schmuck ) forgets to remove the block ( for the 3rd time now ) and it is properly destroyed.

So, I am thinking that I'd like to make a small holder with a limit switch and mount it to the side of the cabinet.
When the parts are loaded, the block must be inserted into this holder to close the limit switch, which in turn allows the program to be started.
To do that, I'd start the program with an M21 on the first block, so nothing happens until the block is in it's proper place ( and not in the machine )

Now the question:
Without the spare M function option, doesn't all Haas machines come with one single MF-In capability?
I was under the impression that they all have it.
My Minimill has a 4 pin round socket on the cabinet labelled M-Function, so I'll be OK on that machine, but what about the others?
I have a VF4 with the old ( '06) control, have a VF4 with the Next-Gen and would like to install this on them as well.

Isn't there a connector on the I/O board where I could wire the switch into?
I don't need the relay output as I'm not signaling anything, just need the machine to halt execution until the external switch is made.

Thanks

Silly question: You don't have probing?

I can't help with your M21 question directly, but I have done something similar on our Brother pallet changer. If both vise wrenches are not in their home (touching limit switches like you're talking about), then the machine will alarm out if it tries to rotate the pallet. It's slick and saves a ton of money in repairs, but you need to make sure your operator can't fuck anything up when they fix the problem and go to start the program again. If reset is pushed, or just cycle start... both need to do something reliable and safe.

Alternatively, what if you installed a 1/4" steel rod (or whatever) coming out the end of your stop so the doors can't even close if numbnuts forgets to take the stop out? Depending on exactly how numb your numbnuts is (and how your door switch override works), that could either work or create even more damage...

Reminds me of the new guy that was an absolute "genius" (his words! LoL) and forgot to take the vise handle off on about day 2 or 3...

to add to Matt's post, tie something to the block (or similar) so it can't stay in the machine

In answer to the original question, yes all the machines indeed come with the M-fin input, but the connector's label and plug style changed over the years. For example:
1993 mill (Motorola) = the input connector is P22 (a three-pin connector, using the two outer-most pins)
2010-2015 Coldfire-II = the input connector is P4 (four-pin connector, using the two inner pins).

The NGC controller's IO board is completely different, and I believe it now has two inputs rather than just one. I'm not sure how the program handles that unless you can use a direct "IF" statement to query the digital input. Previously that wasn't possible with the pre-NGC controllers but it may be possible with the new one, if they let you read the system parameter for the inputs. I may be wrong, never did an install with NGC yet. Although I own one so I could check at some point...

YdnaD said:

In answer to the original question, yes all the machines indeed come with the M-fin input, but the connector's label and plug style changed over the years. For example:
1993 mill (Motorola) = the input connector is P22 (a three-pin connector, using the two outer-most pins)
2010-2015 Coldfire-II = the input connector is P4 (four-pin connector, using the two inner pins).

The NGC controller's IO board is completely different, and I believe it now has two inputs rather than just one. I'm not sure how the program handles that unless you can use a direct "IF" statement to query the digital input. Previously that wasn't possible with the pre-NGC controllers but it may be possible with the new one, if they let you read the system parameter for the inputs. I may be wrong, never did an install with NGC yet. Although I own one so I could check at some point...

Click to expand...

Thank You

Interesting ... but then how does the M21 supposed to work with only 2 pins being used?
Obviously I've just started looking into this for the first time, but I was under the impression that an M21 command will close an internal relay with dry contact, which in turn
serves as a signal to something external to the control to do whatever it does, and when it's finished, it supposed to close another dry contact to signal back, upon which the control
continues execution.

Me thinks you'd need at least 3 pins for that to work, one being common while the other two is in and out.

As far as an IF statement, I don't have macros enabled on any of the machines.

You're correct, but the relay controlled by the CNC will send outputs "out from the machine" rather than into it.
For the input signal being sent into the machine, essentially you're just clicking the two pins together to conduct that input (such as through a relay contact, switch, etc). If the pins are connected then the input turns on, if not then off [idle]. On this input circuit, the machine is providing its own internal 12-VDC power to one of the pins, which you are running through your switch/contact which selectively sends it into the other pin where it's sensed by the processor.

For the outputs, they're indeed controlled by relays as you mentioned. You can wire the relay with whatever power you want, depending on what you're controlling with it (solenoid, indicator light, relay, etc). That power source is supplied externally by you, such as a DC power source plugged into the wall nearby, or straight 120VAC if you need that power instead. It sounds like for your process you won't need an output, but that's how you'd handle it if you needed.

Schematics help so I'll attach one from a previous job I had on an old machine using the P22 connector (where the CNC was signaling a PLC computer, but you can substitute that for a switch in your application). Haas has some documentation for their relays but they don't seem to like providing schematics for it, probably because it would be a partial schematic. so take it with a grain of salt

I had a similar problem a while back, thought up several complicated solutions then I tied the removable stop to one of the leveling feet with stainless fishing line through some 3/8 air hose long enough be out of the way while loading but doors wouldn't close with the air hose in between them. The operator would remember when the machine wouldn't start.