Lathe controller
02 Feb 2017 11:49 #87148
by kor
Lathe controller was created by kor
Hi I am in the planing stages of building a lathe:
2 axis with turret (8 or 12 stations) 6 Gear ratios and a VFD (closed loop steppers)
an MPG is a must.
This lathe should be able to thread (spindle encoding)
Most people so far suggested to go to linuxcnc.
I have 2 mills running on Mach3 and I did build the controller (LPT)
So I am not a complete newbie to the world of CNC.
But the question is what hardware should I get.
Especially if I go with Mesa cards.
There are like a million options.
the 5i25 7i76 plug and go kits seem fairly popular.
but there is also the 7i76e which seems to me like the complete plug and go package
but there are so many cards and they are so difficult to compare.
I haven't found a table comparing there features anywhere.
I am very gratefull for your input.
2 axis with turret (8 or 12 stations) 6 Gear ratios and a VFD (closed loop steppers)
an MPG is a must.
This lathe should be able to thread (spindle encoding)
Most people so far suggested to go to linuxcnc.
I have 2 mills running on Mach3 and I did build the controller (LPT)
So I am not a complete newbie to the world of CNC.
But the question is what hardware should I get.
Especially if I go with Mesa cards.
There are like a million options.
the 5i25 7i76 plug and go kits seem fairly popular.
but there is also the 7i76e which seems to me like the complete plug and go package
but there are so many cards and they are so difficult to compare.
I haven't found a table comparing there features anywhere.
I am very gratefull for your input.
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02 Feb 2017 12:45 #87149
by andypugh
Why not run your lathe from the parallel port too?
LinuxCNC supports a wide variety of hardware interfaces, including one or several parallel ports.
wiki.linuxcnc.org/cgi-bin/wiki.pl?LinuxCNC_Supported_Hardware
You would need a fairly low-count spindle encoder for the software-based counter to keep up. 400 counts per rev or thereabouts is about the maximum (depending on base-thread rate and spindle speed).
I spent more on Mesa cards for my current lathe than I spent on the (bought-new) lathe that preceded it. I am using the 5i24 which is one of the alternative class of Mesa cards that use 50-pin connectors rather than D-sub. Those have a slightly wider range of daughter-cards. (Though I get the impression that a wider range of cards is not what you want).
Replied by andypugh on topic Lathe controller
I have 2 mills running on Mach3 and I did build the controller (LPT)
Why not run your lathe from the parallel port too?
LinuxCNC supports a wide variety of hardware interfaces, including one or several parallel ports.
wiki.linuxcnc.org/cgi-bin/wiki.pl?LinuxCNC_Supported_Hardware
You would need a fairly low-count spindle encoder for the software-based counter to keep up. 400 counts per rev or thereabouts is about the maximum (depending on base-thread rate and spindle speed).
I spent more on Mesa cards for my current lathe than I spent on the (bought-new) lathe that preceded it. I am using the 5i24 which is one of the alternative class of Mesa cards that use 50-pin connectors rather than D-sub. Those have a slightly wider range of daughter-cards. (Though I get the impression that a wider range of cards is not what you want).
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02 Feb 2017 13:06 #87150
by kor
Replied by kor on topic Lathe controller
From my current mills I know a LPT port is rather limited with IOs
with a lathe having a turret I would already max out all IOs
turret needs step dir sensor for locked and positions
limit and home switches So I pretty much get over the limit of one LPT. with an MPG I would max out almost two.
and I heard that driving a VFD over LPT makes quite a few problems.
for threading I need some speed. I calculated that with 120khz I have more than enough. But I wouldn't dream of pressing that through an LPT cable.
I think the LPT is useful to have as additional IOs (if the board has a chargepump)
with a lathe having a turret I would already max out all IOs
turret needs step dir sensor for locked and positions
limit and home switches So I pretty much get over the limit of one LPT. with an MPG I would max out almost two.
and I heard that driving a VFD over LPT makes quite a few problems.
for threading I need some speed. I calculated that with 120khz I have more than enough. But I wouldn't dream of pressing that through an LPT cable.
I think the LPT is useful to have as additional IOs (if the board has a chargepump)
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02 Feb 2017 13:19 #87152
by andypugh
Replied by andypugh on topic Lathe controller
OK, if you have considered and rejected the LPT then a 7i76E would be a good fit (you can set it in a mode where 4 of the IO pins act as counters suitable for a pair of MPGs, and then there is a high-speed counter with index for the spindle.
There are cheaper options, if you are on a budget. If you don't mind making your own interface then
store.mesanet.com/index.php?route=produc...83_85&product_id=291
Is very cheap. It connects to an EPP parallel port, but using the port as a data bus, not as IO.
You should also consider[1]
www.pico-systems.com/univstep.html
And
www.generalmechatronics.com/en/linuxcnc
[1] Or, at least, I feel that I am obliged to mention, in the interests of impartiality.
There are cheaper options, if you are on a budget. If you don't mind making your own interface then
store.mesanet.com/index.php?route=produc...83_85&product_id=291
Is very cheap. It connects to an EPP parallel port, but using the port as a data bus, not as IO.
You should also consider[1]
www.pico-systems.com/univstep.html
And
www.generalmechatronics.com/en/linuxcnc
[1] Or, at least, I feel that I am obliged to mention, in the interests of impartiality.
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02 Feb 2017 13:47 #87155
by kor
Replied by kor on topic Lathe controller
thank you. I have never heard of those two. Since I live in Germany the supply of the hardware you mentioned isn't very good. Mesa is not good either but at least I know one supplier.
Is there any diffrence between a plug n go 5i25 with an 7i76 and an 7i76e?
As far as I know the ethernet port wasn't supported by linux cnc (at least not the smoothstepper and Pokeys (Ethernet))
Is there an advantage in using the 5i25 a big cable and the 7i76? (they are roughly the same price as the 7i76e)
if one uses the 7i76e will it connect to my hub and than to the pc? or do I need a direct connection?
Is there any diffrence between a plug n go 5i25 with an 7i76 and an 7i76e?
As far as I know the ethernet port wasn't supported by linux cnc (at least not the smoothstepper and Pokeys (Ethernet))
Is there an advantage in using the 5i25 a big cable and the 7i76? (they are roughly the same price as the 7i76e)
if one uses the 7i76e will it connect to my hub and than to the pc? or do I need a direct connection?
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02 Feb 2017 14:00 #87156
by andypugh
CNCmonster? www.shop.cncmonster.de/LinuxCNC:::84.html
There is also eusurplus.com/index.php?route=product/category&path=63
And www.duzi.cz/shop_cnc/index.php?main_page=index&language=cz
linuxcnc.org/docs/2.7/html/getting-start...th_preempt_rt_kernel
Other than that they are about equivalent. The 7i76E has more potential IO, as there are two rather than one extra ports.
Replied by andypugh on topic Lathe controller
thank you. I have never heard of those two. Since I live in Germany the supply of the hardware you mentioned isn't very good. Mesa is not good either but at least I know one supplier.
CNCmonster? www.shop.cncmonster.de/LinuxCNC:::84.html
There is also eusurplus.com/index.php?route=product/category&path=63
And www.duzi.cz/shop_cnc/index.php?main_page=index&language=cz
To use the 7i76E you need to run a preempt-RT kernel rather than the RTAI kernel that is included on the LiveCD.Is there any diffrence between a plug n go 5i25 with an 7i76 and an 7i76e?
As far as I know the ethernet port wasn't supported by linux cnc (at least not the smoothstepper and Pokeys (Ethernet))
linuxcnc.org/docs/2.7/html/getting-start...th_preempt_rt_kernel
Other than that they are about equivalent. The 7i76E has more potential IO, as there are two rather than one extra ports.
I think you need a direct connection. Then you would probably connect to the network with a USB WiFi dongle.if one uses the 7i76e will it connect to my hub and than to the pc? or do I need a direct connection?
The following user(s) said Thank You: kor
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02 Feb 2017 16:30 #87160
by jmelson
Yes, the Pico Systems Universal Stepper Controller might be a good fit. It puts everything in one unit. So, you have E-stop plus 15 general-purpose inputs, 8 solid state relay positions, 4 encoder counters and 4 step generators. Encoder counters that are not associated with a step generator can be used for the spindle encoder and MPG. An add-on board can produce analog 0 - +10 V (or -10 to +10) to control the spindle drive. I'm not sure if the 15 GP inputs are enough for all the features on the lathe.
Jon
Replied by jmelson on topic Lathe controller
Thanks, Andy!You should also consider[1]
www.pico-systems.com/univstep.html
Yes, the Pico Systems Universal Stepper Controller might be a good fit. It puts everything in one unit. So, you have E-stop plus 15 general-purpose inputs, 8 solid state relay positions, 4 encoder counters and 4 step generators. Encoder counters that are not associated with a step generator can be used for the spindle encoder and MPG. An add-on board can produce analog 0 - +10 V (or -10 to +10) to control the spindle drive. I'm not sure if the 15 GP inputs are enough for all the features on the lathe.
Jon
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02 Feb 2017 23:58 #87167
by kor
Replied by kor on topic Lathe controller
OK, I got now quite a few options. I really like the 7i76e so far due to the tiny ethernet capble and the option to expand it if needed.
2MPGs sounds perfect for a lathe. 1 spindle encoder sounds good. Eventhough I would prefer a second.
Is there any disadvantage to using the preempt-RT kernel other than that there is no live cd?
2MPGs sounds perfect for a lathe. 1 spindle encoder sounds good. Eventhough I would prefer a second.
Is there any disadvantage to using the preempt-RT kernel other than that there is no live cd?
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03 Feb 2017 00:10 #87168
by andypugh
I am guessing you are planning on one for the turret? The other option there is a gray-code encoding on GPIO.
I am not clear from Jon's description how many encoders would be available on the USC. Perhaps he can elaborate. I think you were talking in terms of closed-loop steppers, but with the loop closed in the drive?
There might even be an advantage, the preempt-RT kernels are _much_ more up to date than the RTAI ones.
Replied by andypugh on topic Lathe controller
Some firmwares for the 7i76E will have a full set of extra step-generators and encoders on the expansion ports.2MPGs sounds perfect for a lathe. 1 spindle encoder sounds good. Eventhough I would prefer a second.
I am guessing you are planning on one for the turret? The other option there is a gray-code encoding on GPIO.
I am not clear from Jon's description how many encoders would be available on the USC. Perhaps he can elaborate. I think you were talking in terms of closed-loop steppers, but with the loop closed in the drive?
Absolute latency isn't quite as good, but that only matters with software-stepping. With external step-generators it's not so critical.Is there any disadvantage to using the preempt-RT kernel other than that there is no live cd?
There might even be an advantage, the preempt-RT kernels are _much_ more up to date than the RTAI ones.
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03 Feb 2017 00:18 #87169
by kor
Replied by kor on topic Lathe controller
I am planning to use the leadshine closed loop steppers. (So it is within the stepper driver ensemble)
Yes Yes the turret needs one in my opinion to make sure the locking positions are reached before the lock is enabled.
"Absolute latency isn't quite as good, but that only matters with software-stepping. With external step-generators it's not so critical." What does that mean exactly? Will I be stuck at 20 khz stepping frequency? Or Will I move from (I got no Idea what the Mesa cards can actually do) 300Mhz to 298MHz stepping frequency
From my calculation 120khz would give me quite some room.
Yes Yes the turret needs one in my opinion to make sure the locking positions are reached before the lock is enabled.
"Absolute latency isn't quite as good, but that only matters with software-stepping. With external step-generators it's not so critical." What does that mean exactly? Will I be stuck at 20 khz stepping frequency? Or Will I move from (I got no Idea what the Mesa cards can actually do) 300Mhz to 298MHz stepping frequency
From my calculation 120khz would give me quite some room.
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