New project build, problem with second Y axis Stepper motor.

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13 Dec 2022 03:42 #259295 by SteveP_CNC
Hi All,

First post!
Firstly thanks to all who have been involved in these forums, I have only progressed to the stage where I am due to the rich resources contained within this forum. (and plenty of reading!!)

I have built a three axis CNC gantery machine using a RP4, WHB04B-4 pendent, ethercat ECT60 stepper drivers and a DieWu TXI050 I/O card. this has one X stepper, two Y steppers and one Z stepper motors for each respective axis. I currently have all the Electronics/Drivers/Steppers wired up on the bench for testing before installing then onto the finished machine.

So far I have everything working smoothly, the only problem is that I have noticed that one of the Y steppers is not in sync with the other, and no matter where I look I am unable to find where the problem lies If I set up the encoder count of 4000 for each stepper and on the pendant I move each axis by 1mm. Three axis X, Y1 and Z will rotate a full 360 deg turn, however Y2 will only rotate 144 deg 

I have confirmed that all all for motors have a 4000 count encoder on them and the SDO vaue 0x2020 are all the same (4000). as well as the value for  "setp cia402.0.pos-scale 4000" is also the same.

I have swapped both stepper motors and ECT60 drives at seperate times between axis and the problem continues to remain on the Y2 axis, so I believe its not hardware related.

Would appreciate any help anyone could offer. - I have attached the .hal and . ini files for bedtime reading.....,
Attachments:

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13 Dec 2022 09:01 #259305 by rodw
You don't have ane home_sequence in your uni. The 1 Ys should both be -1. Please read docs on homing configuration 

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14 Dec 2022 00:42 #259381 by SteveP_CNC
Hi rodw,

Thanks for the reply. Yes - I have this on my "ToDo" list along with a number of other issues I currently have. I will have a read up on this tonight, although I'm guessing that this is not the reason for the Y1/Y2 ratio error?
From the little reading I have done to date it seems that there are a few Ethercat related problems setting this up correctly? I'm hoping it's not too difficult.

My current Todo list:
1) Solve Y1/Y2 turn ratio error.
2) Homing and limit switches, is it best to connect these to the ECT60 stepper driver inputs, which I have checked, and they are working. Or run these through the DieWu TXI050 Ethernet Input/Output card? Again, more reading involved to figure out how to interface this with LinuxCNC.
3) A couple of times during my testing, and this only seems to happen during the boot up of LinuxCNC, one of the Ethercat salves will "drop Out" however there is no error shown and the program will run normally except the axis's will all swap. For example, if X axis drops out, Y1 stepper will move as if its X, Y2 stepper will move as if its Y1, Z stepper will move as through its Y2 and the Z will simply be ignored. You can imagine what will happen to my Y gantry - it will be twisted out of shape - Not ideal!
I have spotted that the is a HAL parameter called "lcec.slaves-responding" which holds the correct value of 5, So I guess I can check this before any move is allowed - is this possible??
4) On/Off and speed control of the spindle VSD - not urgent as can be performed manually at this stage.

I'm sure more will crop up - but these are the main ones at the moment.

Once I have these small issues solved, I'm happy to fit the steppers to my table - fun times ahead!

Again, it's great to see an active forum helping out the newcomers. Much appreciated.

Steve.

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14 Dec 2022 09:38 #259437 by rodw
I would recommend you use the deiwu. I have a config for it here
github.com/rodw-au/linuxcnc-cia402/blob/...ercat-conf-diewu.xml
Get homing up and running the linuxcnc way, then consider writing a custom homing component. Ref homecomp.comp in 2.9/2.10
You can't get your gantry up without homing switches

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16 Dec 2022 01:40 #259600 by SteveP_CNC
Hi rodw,

Thanks for the advice, DeiWu it will be. I had already spotted your DeiWu configuration information previously (One reason why I was confident in purchasing this unit - cheers) and have it up and running already.

As for the Y1/Y2 ratio issue - I have this solved and it turned out to be a simple ethercat.xml error. As mentioned, I have no experience with the whole linuxCNC world and have relied heavily on piecing together parts of the Hal, ini and xml files from all sorts of LinuxCNC Doc and members forum post.
It turns out that while putting together my ethercat.xml file I needed to change the motor max current and closed loop commands to "5 Amp" and "closed Loop" for all axis to match my steppers.

<sdoConfig idx="2000" subIdx="0"><sdoDataRaw data ="88 13"/></sdoConfig> <!-- Max motor current (5.0) -->
<sdoConfig idx="2011" subIdx="0"><sdoDataRaw data ="01 00"/></sdoConfig> <!-- Closed loop -->

turns out that I left one of the axis (yes, Y2) at 1.5Amps max current and open loop - this effectively meant that this axis could not keep up with the high accel rates which the other three where able to perform and because it was "open Loop" i.e. no feedback, it was not faulting out on any following error.

Glad to say that this is solved, on to homing now.

Cheers.
The following user(s) said Thank You: rodw

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17 Dec 2022 23:39 #259781 by andypugh

So far I have everything working smoothly, the only problem is that I have noticed that one of the Y steppers is not in sync with the other, and no matter where I look I am unable to find where the problem lies If I set up the encoder count of 4000 for each stepper and on the pendant I move each axis by 1mm. Three axis X, Y1 and Z will rotate a full 360 deg turn, however Y2 will only rotate 144 deg 

This might be due to one of the drives being set to a different microstep ratio. 

If the DIP switches are all set the same then this might indicate a faulty drive, 

If you connect two drives to the same step output and see the attached motors move different amounts, then it is this. Though there is a fair chance that neither motor will move, if the output pins can't drive two stepper drives. 
 

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