[flatfnder]

I have an alarm that says "z axis z ch missing". I can clear it out and run a couple more parts before it comes up again so it is an intermittent problem. The book says:

154 Y AXIS Z CH MISSING - Z Reference signal from encoder was not received as expected. All servos are turned off. Can be caused by loose connections, encoder contamination, or parameter error.

I have been trying to find a diagram that shows where the z encoder is located to see if there might be a chip or something causing havoc! Where should I be looking for possible contamination?

Any help would be great!!!

Thanks, Judd

[Machineit]

I have an alarm that says "z axis z ch missing". I can clear it out and run a couple more parts before it comes up again so it is an intermittent problem. The book says:

154 Y AXIS Z CH MISSING - Z Reference signal from encoder was not received as expected. All servos are turned off. Can be caused by loose connections, encoder contamination, or parameter error.

I have been trying to find a diagram that shows where the z encoder is located to see if there might be a chip or something causing havoc! Where should I be looking for possible contamination?

Any help would be great!!!

Thanks, Judd

The encoder should be inside the motor housing on the end of the shaft. Sounds like the encoder is going bad, is dirty, or there is a problem with the wiring. Any liquid getting in there? Also check the wiring on the other end.

Mike

[Haas__man]

Is your problem with your Y axis or the Z?

Usually this alarm means that your encoder will need to be replaced.

You may find that running at 50% rapid or 25% rapidmay stop the alarms to allow you to use the machine until you get the encoder replaced.

You wanted to know where the encoder is.
The encoder is on the end of the motor.
If it is on the Z axis then the motor is on top of the column. If your problem is with the Y axis then the motor is at the back of the machine under the column.
Take out the three screws that hold on the end cap. Then remove the end cap. Then you will see the encoder.
The encoder is held onto the motor with two grub screws on the motor shaft (50 thou alan key) and two screws that attatch the encoder to a flexible mount.
It is possible to remove the encoder without removing the motor. On the Z axis it is easy. On the Y axis it is very awkward but do-able.

If you are replacing the encoder then you will need to reset the grid offset for the axis that you have the problem on. If the axis is the Z axis then you need to be careful as the tool change position will be effected and damage could happen to the tool changer if it is not set correctly.

Hope this helps.

[Al_The_Man]

If the encoder has contamination and you can access the glass disc then de-natured alcohol can be used to clean it with lint free cloth, local opticians can supply both, the problem is is if it is also the reading head that requires cleaning because the head to disc spacing is very small, as a last resort you can pour some over the head and air dry it.
In a pinch I have also removed encoder circuit boards in order to access the reading head, but extreme care is required.
Before going to this extent, it would be worth checking the output at a suitable pin out connection, if a differential encoder then you have Z and /Z (complement).
This can be done with a dc voltmeter if you turn the encoder as slow as possible you should see each pin transition between 0 and 5v on each.
Al.

[flatfnder]

Thanks for the responses! I am running at 25% and it hasn't happened again (knock on wood). I will take off the encoder cover and see if I can clean the glass. Hopefully it is just a little dirty!! Judd