Homing Issue, Urgent !!

[Peter Warcholyk]

G'day Folks,

Trying to home my cmm this morning, and had a strange thing occur.

I have a B&S mistral 070705, running pcdmis 3.7mr3.

Normally, the cmm goes to "home" position in the upper left-hand area of the table.
However, this morning it seems to want to send itself home in the Z axis, all the way down into the table.
I've never seen this before, and had no problems at start up yesterday.

I have tried shutting down my entire system, and then restarting again, same thing.

Of course, I have a ton of work that I am supposed to get done this week before I have a couple of days off.

Any suggestions would be greatly appreciated. Please keep directions simple, as I am not a computer guru.

Thanks in advance.

Blessings,
ZydecoPete

[John Kingston]

When you shut down, did you turn off the controller too? On mine it is a large black box mounted on the back of the computer table. There is a rocker switch located on the right hand side when you are facing the table. I would shut everything down again, including the controller and then restart after about 30 seconds.

[Randy P]

can't help U but why turn your controller off all the time? I leave mine on.

[#2#]

Geez Pete, that is a problem.

Does it move up at all or does it just start moving down right away? I know that mine moves up to a certain point and then moves down away from 'home'. If you manually move the z-axis up all the way before shutting down, when you come in and start it up it will not move up any (duh, it can't) and will just move down away from home.

Do you know how your machine detects home (microswitches, magnetic switches, scale reading, etc.)

I am wondering if your machine is trying to move down away from home but the switch is stuck so it keeps moving.

Is it homing OK in y and x? I bet you can't tell b/c it homes in z and then in y and x doesn't it.

That's all I've got - Sorry

[Jan d.]

It is not obvious to me what can cause this, but here is a question for you: does it go down at full speed? Or is it going down at regular homing speed?

If it goes down at speeds well above homing speed, your scale/scale reader or controller is fried.

If it goes down in regular homing speed, you may have an issue with one of the limit switches, or the readerhead has gone out of alignment.

In both cases it'll be hard to avoid a service call.



Jan.

G'day Folks,

Trying to home my cmm this morning, and had a strange thing occur.

I have a B&S mistral 070705, running pcdmis 3.7mr3.

Normally, the cmm goes to "home" position in the upper left-hand area of the table.
However, this morning it seems to want to send itself home in the Z axis, all the way down into the table.
I've never seen this before, and had no problems at start up yesterday.

I have tried shutting down my entire system, and then restarting again, same thing.

Of course, I have a ton of work that I am supposed to get done this week before I have a couple of days off.

Any suggestions would be greatly appreciated. Please keep directions simple, as I am not a computer guru.

Thanks in advance.

Blessings,
ZydecoPete

[Peter Warcholyk]

Hey Folks,

I have just finished trying John's suggestion, and shut down the controller box as well as the entire system. I let it sit for a few minutes, then started everything up again.

I also released all three axis and moved them a short distance away from the home position.
When I started up again, it "appeared" to start moving home at first.

What it did was it moved only in the Z axis, first up, then started heading down, (no stopping). It did not move in the X or Y axis.
I do not know for certain how this machine detects it's home position, i.e., as per Goodlucks query above.

Thanks for your input so far.

Blessings,
ZydecoPete

[Jan d.]

You lost your home pulse on Z. Re-align your reader head. It does not see the home switch so it runs into the limit switch which apparently causes the direction to change.


Jan.

Hey Folks,

I have just finished trying John's suggestion, and shut down the controller box as well as the entire system. I let it sit for a few minutes, then started everything up again.

I also released all three axis and moved them a short distance away from the home position.
When I started up again, it "appeared" to start moving home at first.

What it did was it moved only in the Z axis, first up, then started heading down, (no stopping). It did not move in the X or Y axis.
I do not know for certain how this machine detects it's home position, i.e., as per Goodlucks query above.

Thanks for your input so far.

Blessings,
ZydecoPete

[John Kingston]

Hey Folks,

I have just finished trying John's suggestion, and shut down the controller box as well as the entire system. I let it sit for a few minutes, then started everything up again.

I also released all three axis and moved them a short distance away from the home position.
When I started up again, it "appeared" to start moving home at first.

What it did was it moved only in the Z axis, first up, then started heading down, (no stopping). It did not move in the X or Y axis.
I do not know for certain how this machine detects it's home position, i.e., as per Goodlucks query above.

Thanks for your input so far.

Blessings,
ZydecoPete

Bummer Pete. I think Jan is correct. You have an encoder going or gone bad.

can't help U but why turn your controller off all the time? I leave mine on.

I don't turn the controller off all the time. This was a suggestion to help solve the problem. I have seen resetting the controller clear up all kinds of "interesting" issues.

[bw_bob]

I would think if an encoder was going out you would be getting an axis chip error message. Thats what happened when I had some go bad.

[inspector212]

Sounds like the Z encoder, 1-800-343-7933, sound like you're SOL. Take early vacation.

[inspector212]

We had an encoder go out two weeks ago. We were getting 2mm deviations in the diameter of a ring gage. No errors though.

[Peter Warcholyk]

Thanks for your suggestions.

I have a call into our local "tech" support. When I find out the issue, I'll post it here.

Blessings,
ZydecoPete

[John Kingston]

Sounds like the Z encoder, 1-800-343-7933, sound like you're SOL. Take early vacation.

Sounds like a good idea. (oh, you weren't talking to me.....)

[ag162]

Good Morning,
After reading these postings,,,this is an interesting prb and I believe that tech support is your only option also. As posted, when an encoder goes out, it almost always gives the axis chip error. It does sound like the z is moving to find itself and failing to return to the Z+ home pos. Good luck with tech sup, I'm definately interested in the fix for this one.

A.Gore

[Jan d.]

I am not sure about this particular machine, but there are many machines out there that have a second track on the glass that provides a very accurate and repeatable home pulse. The first track is for the pulse reading that provides the position information. It is possible that you loose adjustment on just 1 track. The other one may be marginal, but still properly counting. It all depends on tolerance stack-up in the mechanical and electronic parts of the reader head and scale.

If the first pulse reader track goes out, it certainly will start to give you chip errors. If the home pulse track is out, you will just not find the home pulse.

Typically, this is not hard to fix. However, I would not try this myself. The result of failure may be that you screw up the reading on the first track. In the old days, that would give run-aways. Now probably chip errors.



Jan.

Good Morning,
After reading these postings,,,this is an interesting prb and I believe that tech support is your only option also. As posted, when an encoder goes out, it almost always gives the axis chip error. It does sound like the z is moving to find itself and failing to return to the Z+ home pos. Good luck with tech sup, I'm definately interested in the fix for this one.

A.Gore