Mesa 7i80DB to retrofit 4 axis VMC

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19 Nov 2022 22:51 #257126 by matos67
Hi,
I'm in the process of retrofitting a CNC systems SDC30 4 axis VMC.
I previously did a similar machine with mach3. It was an easy and inexpensive setup but
it has too many flaws and is not real time, i regret this choice every time i use this machine.
For now i would like to go with linuxcnc and mesa cards. This stuff looks more like the industrial controls i deal with at my job(FANUC,SIEMENS,HAIDENHAIN).
I would like to go the ethernet way but here in europe the only available FPGA card is the 7i80DB-25.
For my needs i would ad :
2x 7i85S to read 4 axis encoders+1spindle encoder+1tool changer encoder.
They should also manage 4 drives(later 5) with step/dir signals.
1x 7i83 to set the analog spindle speed and drive the tool changer servo.
1 or 2x 7i70 to handle the PLC related inputs.
1 or 2x 7i71 for PLC outputs.
1x 7i74 to interface with the different serial daughter cards
1x 7i73 to wire the control panel 

Can someone tell me if this setup is even possible with linuxcnc or if i could or should go with another set of cards ?
I'm new to linuxcnc but i use Ubuntu currently.
Thank you in advance for your answers.




 

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19 Nov 2022 23:45 #257129 by PCW
Are the axis drives analog or step/dir?

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19 Nov 2022 23:49 #257130 by tommylight

I would like to go the ethernet way but here in europe the only available FPGA card is the 7i80DB-25.
For my needs i would ad :
2x 7i85S to read 4 axis encoders+1spindle encoder+1tool changer encoder.
They should also manage 4 drives(later 5) with step/dir signals.
1x 7i83 to set the analog spindle speed and drive the tool changer servo.

 

All those can be replaced by a Mesa 7i95, 6 axis ste/dir with 6 encoders, but no analog spindle out, Eusurplus had one a few days back, i think.
Other options with 7i80:
7i76 and 7i77, those would have 5 step/dir, 1 spindle analog 0-10V, 6 analog out +-10V and 7 encoders, 64 inputs and 32 outputs, each has another SmartSerial so adding another 2 of 7i70 or 7i71 or 7i73 in any combo without the need for 7i74.
-
General info, all ethernet BIG boards like 7i97 or 7i95 or 7i76E or 7i96S have at least another IDC26 header besides 1 or 2 smart serial ports, so a 7i74 can be attached to those also, but might need firmware flashing.
Also might want to wait for PCW to confirm that as i never used that combo.
You might notice i tend to use more versatile boards, experience taught me. :)

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20 Nov 2022 10:57 #257151 by matos67
I use high end drives with brushless servos on all 4 axis. They are able to handle analog , step/dir or differential commands. The ball screws and the 4th axe are fitted with differential encoders so to close the loop in linuxcnc.
The spindle drive is Mitsubishi freqroll with analog setpoint.
Spindle orientation is done by the drive and PLC command.
I have a spindle encoder with differential output mounted on the spindle to close the loop with linuxcnc.

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20 Nov 2022 11:24 #257154 by matos67
I have been looking after the 7i95 but it's out of stock and i'm afraid the lead time is too long for me. The combo 7i80+7i76+7i77+7i70+7i71 seems interesting. For now it would provide all i need. The problem is if things work correctly i plan to extand the capabilty of this machine by going to 5 axis possibly with turning option and even additional tool mag and why not robot handling. This may bee in two years or more but then i will need to have a minimum of 6 step/dir, 8 encoders, 2 spindle analog and additional Smart serial bords.
The following user(s) said Thank You: tommylight

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22 Nov 2022 20:00 #257368 by matos67
Hello PCW, any thoughts about my project?

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24 Dec 2023 14:57 #289003 by matos67
Hi, i wish a Merry Christmas to all the linuxcnc community.I have been working for almost a year on the mecanical aspects of this retrofit.New turcite, scraping, spindle bearings, adapting new servos on axis and so on...Now i just finished the wiring of the servos and spindle motor/drive.It's time to hook up linuxcnc and mesa cards with the following combo :7i80db 7i77 7i76 7i73.

I use servostar S600 drives from Kollmorgen on all axis and i would like to control them in velocity mode with the analog /-10 of the 7i77 card.The position loop is done with encoders mounted on the ballscrews and connected also to the 7i77.
I'm really confused in the way the analog interface is described in the 7i77 manual.  
If i get it right the wiring would be:
servostar Analog-in 1+  ---> 7i77 AOUTN
                Analog-in 1-   --->7i77 GNDN(adjacent to AOUTN)
                AGND            --->7i77  ?
Firstly it seem's there is a confusion in the in the manual between GNDN(in the descrition of the interface) and GND(connector description).
I'm searching which 7i77 terminal would be called  CNC-GND from the servostar point of view and also to what terminal attach the shielding?

The spindle drive is Siemens sinamics S20.
Due to its ability to be driven in bipolar analog mode i would like to control it with 7i77 analog output to try to achieve M19 orientation with spindle encoder hooked to 7i77 or 7i76.
Siemens V20 Al 1  ---> 7i77 AOUTN
                   0V       ---> 7i77 GNDN(adjacent to AOUTN)
                GND       --->7i77  ?
Again i'm confused with how to wire up the digital ground and the shielding.

Thank you in advance for your support!

 
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24 Dec 2023 15:33 #289005 by PCW
The 7I77 GND needs to be connected to CNC ground to establish the common mode
for the analog signals.

You could do this by connecting the AGND pins to both IN- and CNC-GND pins at the
drive end.

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24 Dec 2023 15:52 #289006 by matos67
Hi PCW, If i get you right my drives have differential input but the 7i77 has no differential output.
The 7i77 GND is the GNDN terminal adjacent to the AOUTN terminal and this is where i connect my CNC-GND and shield?

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24 Dec 2023 17:05 #289009 by PCW
Yes, that's correct.

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