[iowa_jim]

I've been searching the forums recently looking to see if someone has already posted about the same problem I am having, but I haven't had any luck.

Here's a little background:

I bought a Bridgeport series II back in August. It was hooked up to power, so I fired it up, homed it, ran a simple program, and bought it. I could tell it was originally owned by GM just by looking at all of the asset tags on it.

It has an Allen Bradley 1386 servo drive system on it for the X, Y, & Z axes. The controller is a Heidenhain TNC355. Feedback to the computer is by Heidenhain LS 403 C scales on the X & Y axes, and a ROD 559 rotary encoder for the Z axis.

When I brought the machine back, I hooked it up, taught myself how to conversationally program it, and made a few parts. During that time, I had some issues with a gross positioning error C. With a little time and resetting, this error was an annoyance, but didn't render the machine inoperable.

Now for the real problem:

A few weeks ago, I fired up the machine to start work on a fuel rail for my Audi. I started up the machine and turned on the control. Once the control is on and memory test completed, I press the handwheel button to turn on power to the servo amp boards. The Y axis lurches, the machine shakes, and the control starts flashing "Gross Positioning Error D" or:

Standstill supervision

- The position deviation from the nominal
position of an axis at standstill is
greater than programmed in machine parameter
169.

- When positioning beyond the target point
programmed the value of the nominal
position is greater than programmed
in machine parameter 169.

I hadn't even had a chance to home it.

I assumed this meant I have a problem with closed loop control with my Y axis somewhere. I did a little testing and found that after the control is on but before the servo amp boards are powered, I can rotate the belts and see linear scale feedback on the X and Y axis, so they're not the problem. I then pulled off the Y axis motor and checked the tachometer; all was good there. I switched the X and Y servo boards and restarted the machine again; it didn't solve the problem either. I checked continuity from the tachometer brushes up to the servo boards and the Ohms were in the single digits.

I am out of ideas as to what is wrong with the machine outside of the controller itself. Is there an Easy way to check if the Differential velocity command input is giving an appropriate voltage(of about 0 volts, I assume)?

Any help would be appreciated. I have quite a few pics of various components that I thought may help. I'll get them loaded in the near future.

Thanks,

[RMARCH]

I've been searching the forums recently looking to see if someone has already posted about the same problem I am having, but I haven't had any luck.

Here's a little background:

I bought a Bridgeport series II back in August. It was hooked up to power, so I fired it up, homed it, ran a simple program, and bought it. I could tell it was originally owned by GM just by looking at all of the asset tags on it.

It has an Allen Bradley 1386 servo drive system on it for the X, Y, & Z axes. The controller is a Heidenhain TNC355. Feedback to the computer is by Heidenhain LS 403 C scales on the X & Y axes, and a ROD 559 rotary encoder for the Z axis.

When I brought the machine back, I hooked it up, taught myself how to conversationally program it, and made a few parts. During that time, I had some issues with a gross positioning error C. With a little time and resetting, this error was an annoyance, but didn't render the machine inoperable.

Now for the real problem:

A few weeks ago, I fired up the machine to start work on a fuel rail for my Audi. I started up the machine and turned on the control. Once the control is on and memory test completed, I press the handwheel button to turn on power to the servo amp boards. The Y axis lurches, the machine shakes, and the control starts flashing "Gross Positioning Error D" or:

Standstill supervision

- The position deviation from the nominal
position of an axis at standstill is
greater than programmed in machine parameter
169.

- When positioning beyond the target point
programmed the value of the nominal
position is greater than programmed
in machine parameter 169.

I hadn't even had a chance to home it.

I assumed this meant I have a problem with closed loop control with my Y axis somewhere. I did a little testing and found that after the control is on but before the servo amp boards are powered, I can rotate the belts and see linear scale feedback on the X and Y axis, so they're not the problem. I then pulled off the Y axis motor and checked the tachometer; all was good there. I switched the X and Y servo boards and restarted the machine again; it didn't solve the problem either. I checked continuity from the tachometer brushes up to the servo boards and the Ohms were in the single digits.

I am out of ideas as to what is wrong with the machine outside of the controller itself. Is there an Easy way to check if the Differential velocity command input is giving an appropriate voltage(of about 0 volts, I assume)?

Any help would be appreciated. I have quite a few pics of various components that I thought may help. I'll get them loaded in the near future.

Thanks,

It may have something to do with the amount of " LAG " at a stand still.
Did you recently have to reload the Parameters ?

[Karsue]

I've been searching the forums recently looking to see if someone has already posted about the same problem I am having, but I haven't had any luck.

Here's a little background:

I bought a Bridgeport series II back in August. It was hooked up to power, so I fired it up, homed it, ran a simple program, and bought it. I could tell it was originally owned by GM just by looking at all of the asset tags on it.

It has an Allen Bradley 1386 servo drive system on it for the X, Y, & Z axes. The controller is a Heidenhain TNC355. Feedback to the computer is by Heidenhain LS 403 C scales on the X & Y axes, and a ROD 559 rotary encoder for the Z axis.

When I brought the machine back, I hooked it up, taught myself how to conversationally program it, and made a few parts. During that time, I had some issues with a gross positioning error C. With a little time and resetting, this error was an annoyance, but didn't render the machine inoperable.

Now for the real problem:

A few weeks ago, I fired up the machine to start work on a fuel rail for my Audi. I started up the machine and turned on the control. Once the control is on and memory test completed, I press the handwheel button to turn on power to the servo amp boards. The Y axis lurches, the machine shakes, and the control starts flashing "Gross Positioning Error D" or:

Standstill supervision

- The position deviation from the nominal
position of an axis at standstill is
greater than programmed in machine parameter
169.

- When positioning beyond the target point
programmed the value of the nominal
position is greater than programmed
in machine parameter 169.

I hadn't even had a chance to home it.

I assumed this meant I have a problem with closed loop control with my Y axis somewhere. I did a little testing and found that after the control is on but before the servo amp boards are powered, I can rotate the belts and see linear scale feedback on the X and Y axis, so they're not the problem. I then pulled off the Y axis motor and checked the tachometer; all was good there. I switched the X and Y servo boards and restarted the machine again; it didn't solve the problem either. I checked continuity from the tachometer brushes up to the servo boards and the Ohms were in the single digits.

I am out of ideas as to what is wrong with the machine outside of the controller itself. Is there an Easy way to check if the Differential velocity command input is giving an appropriate voltage(of about 0 volts, I assume)?

Any help would be appreciated. I have quite a few pics of various components that I thought may help. I'll get them loaded in the near future.

Thanks,

With Heidenhain control usually there is a red botton back in the electrical & control cabin and if I am not wrong it is taged by S3 (In some machine manufacturer it is not there), you should power off whole machine and some one press this botton and other person turn on the machin (this S3 botton has to be continiously keep pressing) and the other person start to move all the axis one by one then you can do referencing and then you can release the S3 botton.
I hope it would help.

[holbieone]

With Heidenhain control usually there is a red botton back in the electrical & control cabin and if I am not wrong it is taged by S3 (In some machine manufacturer it is not there), you should power off whole machine and some one press this botton and other person turn on the machin (this S3 botton has to be continiously keep pressing) and the other person start to move all the axis one by one then you can do referencing and then you can release the S3 botton.
I hope it would help.

The red button is for backing an axis off an over travel hard switch

Sounds like you have a bad drive , when one side of the drive goes it will run out like that

[iowa_jim]

Thanks for the replies.

It may have something to do with the amount of " LAG " at a stand still.
Did you recently have to reload the Parameters ?

No, the parameters are the same ones I was using when I was running the machine. I've modified some parameters since the machine has stopped working properly(I can't remember which ones, I don't have my notebook on hand), but I don't believe they are the problem.

With Heidenhain control usually there is a red botton back in the electrical & control cabin and if I am not wrong it is taged by S3 (In some machine manufacturer it is not there), you should power off whole machine and some one press this botton and other person turn on the machin (this S3 botton has to be continiously keep pressing) and the other person start to move all the axis one by one then you can do referencing and then you can release the S3 botton.
I hope it would help.

I haven't tried this or seen the button. When I get back to the machine, hopefully tomorrow, I'll be able to check it out. If it's just used to back an axis off an over travel switch, then it won't do me much good. I'm not on an over travel switch.

Sounds like you have a bad drive , when one side of the drive goes it will run out like that

I was worried that this might be the issue at the beginning, but I have the same problem when I switch boards(Only the y axis acts up. The x axis is fine with both x and y driver boards.)

I think I'll probe the velocity control inputs to all three boards; if the voltage to the Y axis is different from the X and Z, it will make me feel a little better inside knowing I found an error.

[Karsue]

First check continuty on your feed back cable from encoder to controller and your incoming power cable and voltage to the motor and at the end your encoder.

[gridley51]

A few weeks ago, I fired up the machine to start work on a fuel rail for my Audi. I started up the machine and turned on the control. Once the control is on and memory test completed, I press the handwheel button to turn on power to the servo amp boards. The Y axis lurches, the machine shakes, and the control starts flashing "Gross Positioning Error D" or:

Standstill supervision

- The position deviation from the nominal
position of an axis at standstill is
greater than programmed in machine parameter
169.

- When positioning beyond the target point
programmed the value of the nominal
position is greater than programmed
in machine parameter 169.

I hadn't even had a chance to home it.

I assumed this meant I have a problem with closed loop control with my Y axis somewhere. I did a little testing and found that after the control is on but before the servo amp boards are powered, I can rotate the belts and see linear scale feedback on the X and Y axis, so they're not the problem. I then pulled off the Y axis motor and checked the tachometer; all was good there. I switched the X and Y servo boards and restarted the machine again; it didn't solve the problem either. I checked continuity from the tachometer brushes up to the servo boards and the Ohms were in the single digits.


Thanks,

You could try cleaning the tacho comm with a pencil eraser.It wouldn`t do any harm to remove the main brushes either and give it a blow out with dry air.

[laamar]

We've had trouble like on occasions and find the brushes in the drive motor worn down, a quick change of these and the problems goes.