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Author Topic: Probing and touch plates - your MSM experience?  (Read 32034 times)

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Re: Probing and touch plates - your MSM experience?
« Reply #10 on: August 05, 2010, 12:14:13 PM »
Hi,
plese send me a PM or email with your email address - I'll send you some info about how to get some debug info for me to look at.
Dave

Dave,

I'm haven't yet moved up to SS..

Mach 3.043.010
MSM Beta 2
PP
Homebuilt Probe


Thanks
Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com
Re: Probing and touch plates - your MSM experience?
« Reply #11 on: August 07, 2010, 01:24:11 AM »
Hi readers -
Ventuseu's issue is still under investigation.

Currently, I suspect a problem resulting from the use of a "pin multiplexing" break out board. These type of boards are not pure hardware; they depend on vendor supplied Mach plug-in. They allow one to put multiple signals on a single mach input pin and time division multiplex the pin. I'm hypothesizing that this causes an incorrect state of the probe input to be read when mach looks at the input signal - which results in the probe operation failing.

So, I'm wondering:
Is anyone else using a multiplexing BoB with MSM to do probing?
If so what brand and model BoB?

Dave
Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com
Re: Probing and touch plates - your MSM experience?
« Reply #12 on: August 11, 2010, 12:59:42 AM »
I don't have a touch plate setup yet, but my probe has been working great!  I cut a part yesterday and found the I needed to cut it again .002 more (due to endmill not being the size I thought it was).  Loaded it back in the vice touched off the corner again and ran the modified program.  Worked great!

My only comment,  I wish you had the ability to center on a single axis.  I remember at the Ann Arbor workshop you said you had the routines, just did not install them due to screen confusion.  There's got to be some way to squeeze it in.

Also did a probe along edge to check my vice for square.  It worked, but how do I rotate the axis to correct this tiny error?
Re: Probing and touch plates - your MSM experience?
« Reply #13 on: August 11, 2010, 03:58:46 PM »
We choose not to support rotating the WC system based on vise misalignment in MSM.
The reason is that mach does not rotate jogging when the the WC system is rotated.

Mach jogging is always aligned with the machine axes.
I personally consider that a bug in mach - but it is what it is.

Thus jogging in combination with a rotated WC results in odd side effects.
If you think you are jogging along X in the WC, you are also probably moving in Y and/or Z in WC...

That would be too confusing, so the edge measure facility can be easily used to we measure a vise alignment and MSM simply reports the measurement.

Tap the vise to get it aligned and skip the whole set of issues associated with rotating the WC to match vise.

Re: other probing abilities: I have to say that these will not be coming for MSM anytime soon. I kind of have my hands full with the support of the features MSM already has. But I have added the request to my "things people would like list".


Dave
« Last Edit: August 11, 2010, 04:21:30 PM by DaveCVI »
Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com
Re: Probing and touch plates - your MSM experience?
« Reply #14 on: August 11, 2010, 04:33:51 PM »
Too bad, I'd like to see that feature on "things people would like list" also.  My issue is that my vice has a boss that sets into a slot in the table, this allows me to just put the vice on the table and it's lined up, but it's not perfect it's slightly off.  It's close enough that for most things I do that I could just use it as is, but it would be nice if I could rotate that axis ever so slightly to correct it.  The jogging issue is probably only an issue if it's rotated significantly, even still your jogging so you can correct as you go, your not cutting while jogging.  Just my .02

I got a feel for how big of a project this was in your session at the CNC workshop.  I understand how busy you are and I thank you for all of your hard work!  

Re: Probing and touch plates - your MSM experience?
« Reply #15 on: August 11, 2010, 04:48:39 PM »
FYI - I have the same issue..
I bought the nice little key kit for the bottom on my Kurt D688, thinking how nice it would be to just set the vise down and have it aligned. To my surprise the keys cause the vise to be off by 0.003 over about 5" - in hind sight, I don't know what I was expecting given that my table slots are rough finished on the inside vertical surfaces.
The keys do make a nice repeatable mount angle... just not the angle I wanted - so I made some keys of the right dimensions to place the vise in alignment with X when it is put on the table.

I also tend to like soft jaws for this reason - cut the jaws and I know the lip I just cut is now nicely aligned with X.

Dave

 
Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com

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Re: Probing and touch plates - your MSM experience?
« Reply #16 on: August 13, 2010, 11:58:12 AM »
Dave
I see you mention that you can connect all of the touch plates and probes together (in series I am guessing) to use only 1 input. You do mention this in the instructions and even show a wiring diagram of which I am having a hard time grasping. My (Zarzul's actually) probe is active low"x" and the touchplate is opposite, correct? At 1 time, when I first installed it. I had my probe connected incorrectly or the way you are reffering to and it seemed like all was well but the led's rersponse. Am I missing something? Between the ears? Help fill that void with knowledge!
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: Probing and touch plates - your MSM experience?
« Reply #17 on: August 13, 2010, 01:28:22 PM »
Hi,
I'll try to give a bit of explanation, but it will probably be incomplete....

This topic is one where, if you understand TTL electronics, the schematic in the manual will be pretty obvious (in which case you don't need to be given a schematic to follow). If you don't speak TTL logic, the schematic is not of much help....  :(

I kind of knew when I included the schematic that I was in a damned if I do, damned if I don't situation...    :-\

Here are the core concepts:
Most BoBs have a resister on the board to pull an unused input high. This prevents floating inputs from being triggered by noise etc.
If you connect a normally open switch from the BoB input to gnd, you have created an "active low input" sensor.
Push the switch, the input line is shorted to ground, mach sees the input go active (active low). Release the switch, the resister pulls the input back high and mach see the input go inactive (it's high and the input is "active low").

If you connect 2 or three switches **in parallel*** to the input, any one of the switches will create the active low input signal to mach.

In electronics land this is called "wried-or'ing" inputs. The name comes from boolean logic: the input state = Switch 1 OR switch 2 OR .... switch N closed. 

A little thinking about this will hopefully result in understanding why this only works for active low input devices in parallel. Think about what happens if the switches were normally closed instead of normally open...

This also does not work for combination of active high and active low devices. To make a combination work as desired, what's needed to get touch plates and probes all on the same input pin. The different devices have to converted to all present active low TTL signals to the input pin. The schematic in the manual shows a way to take one acitive high device (a typical probe) and two active low devices (the touch plates) and connect all three to the probe input pin (the schematic is for a Bob that uses TTL input voltage levels).

Hopefully, this helps. If not, the choices are to
1) start learning more about TTL electronics (before doing somethign that "let's the magic smoke out"  of your BoB or other electronics, or
2) Find someone that knows enough electronics to build you an interface card (pehaps similar to the schematic in the manual), or
3) call your favorite BoB vendor and tell them there is a market opportunity if they include this feature in a BoB...  ;)

Dave




Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com

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Re: Probing and touch plates - your MSM experience?
« Reply #18 on: August 13, 2010, 01:45:35 PM »
I have a hobby cnc pro board and have been using pin 15 for my input. I am not sure about the pull up resisitor though I do know about the "Magic Smoke", I tried it once, maybe twice. Didnt see any real magic in it. I will be back rewired!
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)

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Re: Probing and touch plates - your MSM experience?
« Reply #19 on: August 13, 2010, 02:02:53 PM »
The board provides no interface circuitry except pullup resistors on pins 10, 11, 12, 13 and 15. (Pins
1, 14, 16 and 17 are available on the board but do not have pullup resistors).
The board provides no conditioning for any of these pins - just a pass-thru
connection.

I see the need for the parallel connections so any 1 of the (now) 3 N.O. switches can trigger it. My board appears to have the pullup resistor built into pin 15 (the 1 use presently for my probe). Til this point I have been running a touch plate (moveable) and a probe seperately but changing the active low status with each application. I am beginning to see the light. I just need to look at your circuit a few more times and figure out which side of the board to get this 5v from? Or if that is needed.

Due to budget cuts, the light at the end of the tunnel has been extinguished.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)