Fanuc servo drive integration
05 Feb 2017 00:40 #87321
by andypugh
Can you elaborate on how that works? like, what do the pwm amplitudes need to do, in response to the commutation signals?
At the moment I am just confused. I can't even imagine how separate PWM signals for FWD and REV would work.
Replied by andypugh on topic Fanuc servo drive integration
Just to recap: I confirmed each drive has 6 PWM channels, 3-CW, 3-CCW. I need to drive 5 Axis on this machine.
Can you elaborate on how that works? like, what do the pwm amplitudes need to do, in response to the commutation signals?
At the moment I am just confused. I can't even imagine how separate PWM signals for FWD and REV would work.
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05 Feb 2017 01:04 #87323
by Diederik
Replied by Diederik on topic Fanuc servo drive integration
Hi Andy,
I Apologise. I had to translate from afrikaans, so I think I misunderstood my friend.
His answer was 3PWM+, 3PWM-
So also after looking at your attachment, I think it's supposed to be as follows:
phase-A
phase-B
phase-C
phase-A-inverted
phase-B-inverted
phase-C-inverted
Will this be my connections?
Sorry... I think I misunderstood the first time.
I Apologise. I had to translate from afrikaans, so I think I misunderstood my friend.
His answer was 3PWM+, 3PWM-
So also after looking at your attachment, I think it's supposed to be as follows:
phase-A
phase-B
phase-C
phase-A-inverted
phase-B-inverted
phase-C-inverted
Will this be my connections?
Sorry... I think I misunderstood the first time.
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05 Feb 2017 01:28 #87325
by andypugh
Replied by andypugh on topic Fanuc servo drive integration
That makes _so_ much more sense.
Basically that is the direct-drive signals for each element in the 3-phase bridge:
en.wikipedia.org/wiki/Power_inverter#Three-phase_inverters
The Mesa 3-phase PWM can drive those, and the HAL "bldc" component can interpret the 4-line commutation signal to drive the Mesa 3-phase PWM.
So, all you really need to join-the-dots is a Mesa firmware with all 6 PWM outputs.
Basically that is the direct-drive signals for each element in the 3-phase bridge:
en.wikipedia.org/wiki/Power_inverter#Three-phase_inverters
The Mesa 3-phase PWM can drive those, and the HAL "bldc" component can interpret the 4-line commutation signal to drive the Mesa 3-phase PWM.
So, all you really need to join-the-dots is a Mesa firmware with all 6 PWM outputs.
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05 Feb 2017 05:44 #87331
by Diederik
Replied by Diederik on topic Fanuc servo drive integration
Thank you Andy.
Will my configuration as follows be sufficient?
I would love to know which mesa cards to use for pwm. Andy, you mentioned about a fpga card to use. What would you suggest? Will something like a 7i80DB work? together with a 7i75? I suppose I will need 30 I/O for a 5 axis machine with pwm. so my configuration for this machine can be as follows:
7i80DB => J2 => 7i75 => PWM
=> J3 => 7i75 => PWM
=> J4 => 7i77 => 7i84(SS)
=> J5 => 7i77 => 7i84(SS)
Will my configuration as follows be sufficient?
I would love to know which mesa cards to use for pwm. Andy, you mentioned about a fpga card to use. What would you suggest? Will something like a 7i80DB work? together with a 7i75? I suppose I will need 30 I/O for a 5 axis machine with pwm. so my configuration for this machine can be as follows:
7i80DB => J2 => 7i75 => PWM
=> J3 => 7i75 => PWM
=> J4 => 7i77 => 7i84(SS)
=> J5 => 7i77 => 7i84(SS)
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05 Feb 2017 23:43 #87375
by andypugh
Replied by andypugh on topic Fanuc servo drive integration
I don't think an ethernet card would be my first choice. I think I would look at a PCI 50-pin card like the 5i23.
There is a firmware definition that defines all 6:
github.com/LinuxCNC/hostmot2-firmware/bl...c/PIN_TPEN6_6_72.vhd
and github.com/LinuxCNC/hostmot2-firmware/bl...c/PIN_TPEN4_5_48.vhd
And it looks like it gets built for some cards:
github.com/LinuxCNC/hostmot2-firmware/blob/master/firmwares.txt
Note that this is the code that makes the linuxcnc-firmwares package, and it doesn't cover some of the newer cards, but does include some firmwares that Mesa don't distribute.
It looks like you could get a 5i23 and get a 6-channel firmware easily.
But the 5i23 isn't the cheapest card, and the 5i24 is just as capable.
Though, that is only part of the puzzle. What feedback do you get from the motors for commutation?
There is a firmware definition that defines all 6:
github.com/LinuxCNC/hostmot2-firmware/bl...c/PIN_TPEN6_6_72.vhd
and github.com/LinuxCNC/hostmot2-firmware/bl...c/PIN_TPEN4_5_48.vhd
And it looks like it gets built for some cards:
github.com/LinuxCNC/hostmot2-firmware/blob/master/firmwares.txt
Note that this is the code that makes the linuxcnc-firmwares package, and it doesn't cover some of the newer cards, but does include some firmwares that Mesa don't distribute.
It looks like you could get a 5i23 and get a 6-channel firmware easily.
But the 5i23 isn't the cheapest card, and the 5i24 is just as capable.
Though, that is only part of the puzzle. What feedback do you get from the motors for commutation?
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06 Feb 2017 02:56 #87379
by Diederik
Replied by Diederik on topic Fanuc servo drive integration
Thanks Andy.
I was under the impression that the Ethernet cards is the way forward? And I quite like it, because I can now have my computer in operators panel, away from switchgear enclosure.
If you recommend 5i23, won't the 7i80hd, and 7i90hd do the job just as well? If any specific reasons, I understand, but I don't have a pc with a pci slot at the moment. I'll have to source one. ..
I was under the impression that the Ethernet cards is the way forward? And I quite like it, because I can now have my computer in operators panel, away from switchgear enclosure.
If you recommend 5i23, won't the 7i80hd, and 7i90hd do the job just as well? If any specific reasons, I understand, but I don't have a pc with a pci slot at the moment. I'll have to source one. ..
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06 Feb 2017 07:45 #87381
by jCandlish
Replied by jCandlish on topic Fanuc servo drive integration
Hi Diederik
Is it your intention to use the existing Fanuc servo drives? The servo drives pass the phase info from the servos through to the controller, along with other information.
See gr0kr's post from 2012: forum.linuxcnc.org/30-cnc-machines/20837...ation?start=30#23687
There is more involved than just the phase info.
Is it your intention to use the existing Fanuc servo drives? The servo drives pass the phase info from the servos through to the controller, along with other information.
See gr0kr's post from 2012: forum.linuxcnc.org/30-cnc-machines/20837...ation?start=30#23687
There is more involved than just the phase info.
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06 Feb 2017 08:39 #87382
by Diederik
Replied by Diederik on topic Fanuc servo drive integration
Thanks.
I would like to use the fanuc digital drives.
But what would your honest opinion be? Should I rather just replace the servo drives with analog drives?
seems like this pwm drives can cause headaches... ?
I would like to use the fanuc digital drives.
But what would your honest opinion be? Should I rather just replace the servo drives with analog drives?
seems like this pwm drives can cause headaches... ?
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06 Feb 2017 08:56 #87383
by jCandlish
Replied by jCandlish on topic Fanuc servo drive integration
The Fanuc drives are first rate, as are the servos. The magnetics cabinet is already fitted with a power supply and line filters.
It is the motion control that has become obsolete, and there is also export control restricting the availability of full 5-axis functionality.
You can get quite nice prices for matched servos and drives from CTB in China via Alibaba, but there is a significant amount of work in replacing the old drives and integrating the new.
An interface that talks directly to the existing Fanuc amplifiers and I/O controllers would be the way to go, if it existed.
It is the motion control that has become obsolete, and there is also export control restricting the availability of full 5-axis functionality.
You can get quite nice prices for matched servos and drives from CTB in China via Alibaba, but there is a significant amount of work in replacing the old drives and integrating the new.
An interface that talks directly to the existing Fanuc amplifiers and I/O controllers would be the way to go, if it existed.
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06 Feb 2017 09:54 #87384
by andypugh
I think that all the required parts of the chain exist.
The "bldc" HAL component can interpret the motor commutation information and calculate the 6 PWM amplitudes.
The Hostmot2 3-phase PWM can create the signals and ensure the required dead-time to avoid shoot-through.
I am not saying that it isn't a project, but it should be possible.
Both my machines run all their servos with commutation happening in HAL. It's definitely a workable system.
Replied by andypugh on topic Fanuc servo drive integration
An interface that talks directly to the existing Fanuc amplifiers and I/O controllers would be the way to go, if it existed.
I think that all the required parts of the chain exist.
The "bldc" HAL component can interpret the motor commutation information and calculate the 6 PWM amplitudes.
The Hostmot2 3-phase PWM can create the signals and ensure the required dead-time to avoid shoot-through.
I am not saying that it isn't a project, but it should be possible.
Both my machines run all their servos with commutation happening in HAL. It's definitely a workable system.
The following user(s) said Thank You: Diederik
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