I have a problem that my CNC milling is not accepting the 2nd encoder when configured with the Zero mark.

I have converted the machine from old 811D to New Sinumerik 828D. Everything works fine except for this issue.

When configured through Starter Program to run only with Encoder 1 ( a Hidenhain encoder on top of the motor) it works fine without alarms.

When I configure it with the 2nd Encoder ( TTL encoder fitted to the Spindle shaft -- it is a GS-04T Guboa Encoder) - BUT WITHOUT the Zero Mark  the machine also works fine without any errors. Meaning that I configure the encoder with the correct Resolution of 1024 pulses, but as a No Zero Mark Encoder. The machine works fine without errors.

As soon as I reconfigure the 2nd Encoder WITH One Zero Mark I get the following errors:

Alarm 207566: Encoder Error in Profidrive Encoder Interface 2.2 --- this alarm is displayed immediately as soon as the configuration is downloaded. No need to start the drives ( by the enable pulse signal) - as it will be already displayed.

When Pulse Enable is On and drive started the alarm remains present all the time.

Then when I start the spindle I get the alarms 232131 ( Deviation position too large :8) and Alarm 232100 ( Zero Mark Distance Error : -4). It just turns the pitch of 1 tooth or 2 most of the encoder disk - and the alarm will be immediately displayed!!

I checked the encoder - on the machine ( with machine configured without this encoder and then powering it from an external 5V supply) with an oscilloscope and it looks perfect.

The A and B pulses are correct and the R pulses are also correct ( displayed only once per revolution - as soon as the Zero mark passes infront of the encoder)

I tried all sorts of parameter changes both from the Sinumerik 828d as well as from the Expert list in the Starter software - but still in vain.

I believe that the main cause has to do with the Profidrive but I do not know what is wrong.

As per diagnostics manual for error 207566 it is mentioned to "Acknowledge Encoder error using Encoder control word G2_STW.15 = 1 "  but I cannot figure out how.

Any help will be extremely appreciated as I cannot park the spindle to accept a tool change.

For the rest the machine is working fine.

Please Help !!

Thank you.

Gozitan

Hi Riddersholm

Thanks for trying to help.

Yes I changed all the driving electronics.

I changed the controller to 828d. I Changed also the Motor drive to S120 Combi. I opted for the Combi because it is more compact and it served all the service. 

I also installed a New Reactor and New Filter.

Motors and Encoders were not changed. The Encoders were connected to the Combi through SMC20 Sensors. 

So I have 4 SMC20's - one for each axis X, Y, Z and another for the Spindle Motor.

The 2nd Encoder of the Spindle is connected to the Combi directly through the D15 port found at the front of the Combi.

Yes I can surely share an .ard file, but I never did it. Can you send me a simple procedure how to extract it please?

Help how I can configure the 2nd Encoder will be greatly appreciated,

Thanks Riddersholm.

I  will be in the tool shop tomorrow. So I will download the .ard and send it to you.

For the  X220 I have made a wire connection converting the D25 plug coming from the Encoder ( which originally was being connected to the X 416 of the 810D ) and connected the pins accordingly to match the data of the D15 pinout on the X220. ( I used both the manuals of S120 combi and old 810D drive to ensure that I am connecting everything correctly

I have all the notes at home - am currently out -. Will send you the exact mapping of how I set up the wire later on tonight.

I had soldered the joints to make this converter cable and afterwards tested them with a multimeter to ensure that there supposed pinouts are well connected and there is no short with any of the other pins.

All was fine.

I still suspect that it is picking up electromagnetic noise at the solder joints - so I purchased a D15 wire with the plug at one end and loose wires at the other end. Then for the D25 - I have purchased a plug where I can connect them in a simple Terminal block rather than having them soldered.

I will be connecting this wiring tomorrow and test it.

When testing the encoder using the oscilloscope - I am using a D25 long wire . And as I said all the signals are fine.

But in using a D25 plug - I cannot pass through this converter cable that I made.

So in reality I am testing everything except for the converter wire.

Now today I will be purchasing a D25 to D15 converter so that I can use the same test wire that I have been using ( D25 at one end and open ends at the other end) and ensure that I do not exclude this converter cable.

I will test it tomorrow night and will inform you about the outcome.

Thanks for all the help and follow up.

Regards 

Gozitan

Hi Riddersholm.

I changed the cable to the new one that I have mentioned and it worked !!

I am sure that I have tested the connections of the original cable both for correct pin to pin mapping as well as any shorts with adjacent pins and am sure that it was ok as I have tested it more than once.

I suspect that the issue had to do with some Electromagnatic voltage pickup as this wire now has better shielding in the plugs.

This is the only thing I can suspect.

Attached I am still attaching the ard file for your reference ( it is saved as .txt - just change to .ard)

Now the only problem that remains is that the spindle hums alot at the end of the M19 function.

It rotates slowly for the complete number of degrees set in MD34060 and MD34030 and then when this range is completed the spindle vibrates and soon after the Spindle goes OFF1.

Once I hit the Reset key on the MCP310 keypad to start it again, it starts vibrating again. I quickly hit the Spindle Left or Spindle Right keys and it will run  smoothly and nicely.

Using MDA to run the M19 command again results in Spindle Vibration.

I suspect the issue is happenning when there is the switch from encoder 1 to encoder 2 for control,  but I had no time to check. ( I am not sure how the system works from speed control to the spindle control)

What do you think?

It seems that there is some DB38xx.DBX.yyy command in the PLc which is triggering this vibration as there is a pattern with the activities I trigger in the PLC.

In the end I believe the PLC is correct as I got it from the vendor. So I will look for what is really triggering it, so that then I can find a solution.

What do you think please?

Is there a specific DB38xx command to switch from Speed control ( using Encoder 1) to the Position control ( which must be using Encoder 2)?

I forgot to download the PLC. I will send it to you later.

However it seems that when the system  is forced to be governed by Encoder 2 - it will vibrate.

The resolution of the Top Encoder ( direct to Motor) is 2048 pulses.

The resolution of the 2nd encoder on the Spindle shaft is 1024 pulses.

Using Starter program, I programmed the Spindle to use only the 2nd Encoder without Zero Mark.

When Ran, the spindle Hums / Vibrates alot. It rotates, but with a very humming noise.

Then I quickly reprorammed it to run with the top encoder as well as its humming was alot.

Do you have any recommendations as to which DB3xxx.DBX parameters I should look at in the PLC and what MD parameters I should check for in the Machine parameters please?

Thanks alot for your help.

Regards

Gozitan