Need Help!- 2 problems corrected, but still have another

[bherr]

OK, fixed the reference and no table movement and the gross positioning error, now I get a positioning error, not gross, just positioning error. I loaded a good program that I know is good, but now this. Its almost as if the table doesn't know where its at, if that makes any sense, yet I program the X, Y & Z axis to all 0.0000. If anyone has any ideas I'm all ears.

Ben

[gus]

Well, how exactly did you 'fry up' your machine? If you lost the parameters you also lost all reference info, so yeah, it doesn't know where it is. If you have changed the feed max at some point since you saved your parameters then you will need to tweek your servo drives.

[bherr]

Originally Posted by gus Well, how exactly did you 'fry up' your machine? If you lost the parameters you also lost all reference info, so yeah, it doesn't know where it is. If you have changed the feed max at some point since you saved your parameters then you will need to tweek your servo drives.

Gus,
Not really sure how I messed up the reference and actual positions, but I did. I tried reading the Heidenhain manual last evening, but man they assume your an engineer and really don't explain every step in detail. we've got an ice storm here today, so I won't be out on any service call for satellite work. Hate to miss the income, but ice and autos just don't mix. Hopefully I can start at the beginning of the setup procedures and figure this all out. I think what I did was zeroed out the axis when I was in the actual mod and that threw everything out of wack. thanks for the input.

ben

[machintek]

The position display is changed under the MOD key.
Usually we leave it in nominal so it does not flicker as it does in actual.

George

[bherr]

Originally Posted by machintek The position display is changed under the MOD key. Usually we leave it in nominal so it does not flicker as it does in actual. George

George,
Here's what I'm showing:

In nominal mode X=0.0 y=0.0 z= 0.0 ( I entered the zero's)
In REF mode x=(-)15.2423 y=(-)8.03 z= (-)2.62
In DIST mode x= +154.8597 y= +8.274 z= +2.95
In ACTL mode x= 0.0 y=0.0 z=0.0
In LAG mode x=0.0000 y= 0.0000 z= 0.0000

With the settings above when I load a program and start to run it, I get a positioning error message. All the settings above are with the tool pretty much dead center in all the axis.

the manual states the following:
Setting software limit switch ranges
"go to manual mode and select REF display"
position display shows distance to reference points
"Move all axes via direction buttons or hand wheel in a positive & negative direction to position just before Emergency Stop switch and note display value and sign"
"the noted value is programmed as machine parameters 44 to 51"
"Select display mode ACTL via MOD"

parameters 44 thru 51 are for the x+, X-, Y+,Y- and Z+,Z-. Now the question is do I enter the REF numbers as noted or the ACTL numbers?? If I enter the REF numbers I hit limits almost immediately in X and Y. Haven't tried Z.

Talk about being confused, let alone frustrated.

Ben

[bherr]

Well I contacted Heidenhain via email and explained my problem and here is the message I got back.

Hi Ben,



Positioning error is a benign error, simply pressing the CE key will clear the error message, and you can continue running your program. The message is letting you know you did not make position but it is within the acceptable range chosen in the parameters. Gross positioning errors are critical and require a reboot and for you fix something to regain proper operations.



Both error messages are saying that you have an excessive amount of lag. Excessive lag can be cause by:



1. Incorrect parameter values. But if the parameters are the same ones that use to run the control correctly then it is unlikely they are wrong.

2. Improper lubrication to the axes. Check lubrication lines for blockages, loose or broken connections.

3. Mechanical wear. Ways or Gibbs need to be adjusted or repaired.

4. Worn brushes in the motor or failing armature.

5. Servo drive/s pots have drifted or drive/s are failing. Test by putting control in LAG mode (MP60), LAG display and Metric. Move the axes and compare the Lag values. First check for balance or offset by moving each axis in both direction and comparing the reading in both directions. They need to be the same or as close as possible. Do not take readings when they are ramping up or down and the feed rate must be the same in both directions. Once you have confirmed that the axes are balanced then you need to compare the lag readings for at least the X and Y axis. They also need to be the same or as close as you can make then or you will not be able to create circles correctly and diagonal paths at the correct angle. If you work in the XZ or YZ plane then you have to balance all 3 axes to each other.

I checked the ways and gibs and they are tight, no slop. I tried the LAG thing he talked about, but couldn't quite figure out what he was saying. He also said I could just hit the CE and continue with running the program, that didn't fly at all. So I'm back to square one. double and triple checked the parameters again, but still getting the positioning error.

Ben

[machintek]

What you have told me is that part program zero is set in the center of travel. As long as you command the machine to move within its ability to move in each axis, you should be OK. But the amount of travel is set in the parameters you mentioned.
There is a error called GROSS POSITIONING ERROR which is followed by a letter to be more specific in reason. That is a fatal error and requires a machine shut down and reboot.
Heidenhain is indicating that your error is a result of the actual position lagging behind the expected position by a value greater than allowed in the parameters.
That is why they asked you to put it in lag (which shows the difference between actual and expected position thus a value of zero at standstill) and try jogging in rapid in both directions and watching what the lag value is. Turn the feedrate down and the lag should go down.
Excessive lag is a result of too much friction (gib adjustment, bearings, lack of oil) or the motors not being able to do their job (because of a lack of energy_low voltage, or motor worn out_short brush length, or parameters set wrong_expecting more than machine can deliver).
Are you per chance on a phase converter?
Are the parameters you are putting in from the original parameter sheet that came with the machine? Assuming no control upgrades were done.

George

[holbieone]

i don't know what your control is like but our tnc 426 has battery back up for the scales

when they went dead we had the same errors you have

[bherr]

Originally Posted by machintek What you have told me is that part program zero is set in the center of travel. As long as you command the machine to move within its ability to move in each axis, you should be OK. But the amount of travel is set in the parameters you mentioned. There is a error called GROSS POSITIONING ERROR which is followed by a letter to be more specific in reason. That is a fatal error and requires a machine shut down and reboot. Heidenhain is indicating that your error is a result of the actual position lagging behind the expected position by a value greater than allowed in the parameters. That is why they asked you to put it in lag (which shows the difference between actual and expected position thus a value of zero at standstill) and try jogging in rapid in both directions and watching what the lag value is. Turn the feedrate down and the lag should go down. Excessive lag is a result of too much friction (gib adjustment, bearings, lack of oil) or the motors not being able to do their job (because of a lack of energy_low voltage, or motor worn out_short brush length, or parameters set wrong_expecting more than machine can deliver). Are you per chance on a phase converter? Are the parameters you are putting in from the original parameter sheet that came with the machine? Assuming no control upgrades were done. George

George,
Thanks for the info. This morning I went and reset the software limits, following the BP manual using the metric numbers in the REF display. I then did as you suggested, went into LAG, set the feed rate to around 100 and used the joy stick to move the table. X= 4.29mm to 4.30mm in both directions . Y= 4.4 in both directions and Z was .465 going down and up was 3.9. The Z up was always faster than the Z down. I reloaded a program and again got the positioning error message. Earlier I did have a Gross Position Error A which I corrected.
I checked the auto oiler lines and they appear good. I get lots of oil on the table saddle and the Z spindle has lots of oil on it. I also followed the manual for checking the Gibbs and ways, by applying pressure on the ends of the table with the table in the +X and -X as well as the Y+ and Y-. I could feel any movement at any of the locations, although I didn't use a measuring device. You stated that the LAG is most likely the problem and that I may have to adjust the parameters to compensate. I'm going to go thru the Heidenhain manual again this morning and try a figure out which parameter/s I'll need to change. If you happen to know which ones are the ones I should look at , please let me know. Again as always, thank you for your assistance.

ben

[bherr]

Originally Posted by holbieone i don't know what your control is like but our tnc 426 has battery back up for the scales when they went dead we had the same errors you have

holbieone,

I checked the batteries and they are good, in fact I removed them and let the machine set overnight so that i could re-enter the parameters. As George stated in the post I may have a lagging problem. Just need to figure how to correct that issue. The biggest thing that has me confused is that all this happen when I lost the parameters, due to shutting the machine down from the phase converter without shutting the machine off first. Thanks for your input.

ben

[machintek]

A phase converter, eh?
The parameters are backed up by batteries. They should never be lost unless the batteries go dead, you remove the batteries with the machine off, or you delete the parameters.
Can damage be done to the machine by shutting down the phase converter? I have a service bulletin from Bridgeport that states that warranties are voided if a machine is run on a phase converter. I guess they have had bad experiences with phase converters or had no faith in them. Most create an artificial phase that varies greatly. I do not know if your phase converter can provide enough power to the drives. These controls can be fitted to many different size machines. The parameters are set such that the control knows how to accel, decel, rapid, etc the motors. Is your parameter sheet is wrong, or you are using a phase converter, the ability to accel a given amount of mass may not be there thus giving an error.
Try writing a simple program with no tool change and only one slow feed rate, say the X axis for one inch. You will need to turn the spindle on to do a feedrate. Repeat using a faster feed rate until it faults out. This will prove a point that the machine can move. It will also tell you at what speed it will fault out. You may have to change the parameters for rapid.

George

[bherr]

Originally Posted by machintek A phase converter, eh? The parameters are backed up by batteries. They should never be lost unless the batteries go dead, you remove the batteries with the machine off, or you delete the parameters. Can damage be done to the machine by shutting down the phase converter? I have a service bulletin from Bridgeport that states that warranties are voided if a machine is run on a phase converter. I guess they have had bad experiences with phase converters or had no faith in them. Most create an artificial phase that varies greatly. I do not know if your phase converter can provide enough power to the drives. These controls can be fitted to many different size machines. The parameters are set such that the control knows how to accel, decel, rapid, etc the motors. Is your parameter sheet is wrong, or you are using a phase converter, the ability to accel a given amount of mass may not be there thus giving an error. Try writing a simple program with no tool change and only one slow feed rate, say the X axis for one inch. You will need to turn the spindle on to do a feedrate. Repeat using a faster feed rate until it faults out. This will prove a point that the machine can move. It will also tell you at what speed it will fault out. You may have to change the parameters for rapid. George

George, been running this machine on this phase converter for over a year now and no problems and the guy that owned it before used it with success.