Advanced Search

On your PSU: I have used a similar PSU on a similar project and it worked great. dbtayl's notes on PSU are correct, but another way to success is to use an oversized PSU. According to the specs you seem to be doing so.

So based upon what I'm using you don't think I need to swap out for a different PSU that has said protections?

CAT6A should do if you make sure it is multi-stranded. On a lot of cheap network cable each wire is solid = will break soon if it has to flex a lot. Breaking wires between your motors and drives can fry your drives. Just something to keep in mind.

I feel like this would do good.

On your PSU: I have used a similar PSU on a similar project and it worked great. dbtayl's notes on PSU are correct, but another way to success is to use an oversized PSU. According to the specs you seem to be doing so.

CAT6A should do if you make sure it is multi-stranded. On a lot of cheap network cable each wire is solid = will break soon if it has to flex a lot. Breaking wires between your motors and drives can fry your drives. Just something to keep in mind.

Edit:
Amps and motor drives: I think your choice is just fine.

I see, thanks for this info. I'm probably going to contact either Sherline or the manufacturer of the stepper (if they are still in business) to confirm the amps needed. Just to confirm though, those stepper drivers should work, right?

I plan on just mounting all the hardware on a piece of MDF so I don't think I really need to worry about space just yet. I really just need to get it working, then I can worry about bells and whistles.

Is there a cheap way of acquiring tools for the mill (e.g., cylindrical edge finders, collets, drill bits, end mills, etc)?

Logthor wrote:

I have a question about my servos. From the data sheet, it says that each motor is 2 amps per phase. The data sheet doesn’t seem to mention whether or not this is 2A phase RMS or peak current. The stepper drivers I’ve picked out are 2.1 amps peak for the closest dip setting. Is this fine to drive these servos? I just want to make sure I’m not going to burn up my servos.


 

Setting your drivers at 2.1 amps for your 2 amp motors sounds like a good "starting point" Then once you get it powered up, you can keep an eye on the motors to make sure they're not getting too hot as that is often the final rule whether an amp setting fully fits the motor/application. I don't see the rated operating temperature on the datasheet, as a general rule I like to keep them under 82C (180F), some are rated hotter. The cooler you run them the longer they last.

A stepper powered up and parked at 0 RPM has way more torque than it has while rotating. As a consequence, you can reduce its amps during 0 RPM, greatly reducing its heating. This reduces its holding torque some, so might take experimenting to find whether it is worth that trade-off.
I see your drives list function of sw4:OFF = half current, ON = full current. I suspect that is this feature, might be worth confirming.

@dbtayl on using a big enough enclosure: That is one detail I find too easy to get wrong. Countless times I think I started with a plenty big box. As the project evolves I find it is getting crowded.

Thanks for the info.

Nomenclature nitpick: Unless you've got encoders on there, those are stepper motors, not servos. And even steppers + encoders are typically referred to as "closed-loop steppers", not servos.

I meant to say steppers my mind just slipped I guess.

PSU: If you're going to use a switch-mode PSU, make sure you get a big (uF rating, voltage rating) capacitor to put on it. Motors dump energy into the PSU on deceleration, which can lead to voltage spikes and blown stepper drives and/or PSU. A toroidal/transformer based supply is often recommended instead for this reason.

Noted. The geckodrives are a bit too expensive for me to consider. If you have an recommendations for a good PSU I'm all ears. Additionally, regarding the drivers I have picked out, I assume it is RMS current right in that documentation?

Wire: You may want multi-conductor wire. If that's for the steppers, 4-conductor would be good. Running 4 separate wires to each motor seems unnecessarily obnoxious.

If I use a CAT6a cable will the shielding on it provide enough insulation to avoid being influenced by EMI?

-Coolant/air blast control
-MPG
-Spindle encoder
-Touch probe
-Toolsetter
-Hardware feed hold/single-step/pause/resume/etc. buttons
-Rotary axis

I'm probably just going to use a spray bottle with coolant for the mean time. Not sure what you mean by MPG, the machine I have has manual lead screw handles built in to jog it. I'm going to control the spindle with the 7I96S and hope it spins at the speeds I want while cutting. Touch probe's seem expensive unless there is a cheap one on amazon. Regarding a toolsetter, buttons, and rotary axis, all that seems quite far away atm. I'm going to worry about making it work first.
 

Nomenclature nitpick: Unless you've got encoders on there, those are stepper motors, not servos. And even steppers + encoders are typically referred to as "closed-loop steppers", not servos.


PSU: If you're going to use a switch-mode PSU, make sure you get a big (uF rating, voltage rating) capacitor to put on it. Motors dump energy into the PSU on deceleration, which can lead to voltage spikes and blown stepper drives and/or PSU. A toroidal/transformer based supply is often recommended instead for this reason.

This may also be useful: www.geckodrive.com/support/power-supply-basics/


Wire: You may want multi-conductor wire. If that's for the steppers, 4-conductor would be good. Running 4 separate wires to each motor seems unnecessarily obnoxious.


Missing from your list: buttons, switches, fans, terminal blocks, enclosure, mounting hardware, connectors. Specifically, you'll probably want to put your parts in a box of some kind, and at the very least an e-stop is a good idea. Generally you want that wired such that it hard-cuts power to the motors+spindle of the machine or otherwise renders it in a safe state.

Drawing out everything you'll use and the connections between them can help identify gaps- eg, making sure you have enough terminal blocks. It's shockingly easy to run out of those. Ditto for enclosure space- a little planning goes a long way there, and also getting a bigger enclosure than you think you need.


Finally: I'm not familiar with all the mesa offerings (I've got a 7i76e on my mill, IIRC), but try to think about what you might want in the future and then you can decide whether it's worth buying something with spare I/Os to support it now or accepting you may need to upgrade the card later to add things. Things you might consider:

-Coolant/air blast control
-MPG
-Spindle encoder
-Touch probe
-Toolsetter
-Hardware feed hold/single-step/pause/resume/etc. buttons
-Rotary axis

IIRC you've got a Taig, and IIRC those use ER collets or equivalent... my experience is re-zeroing tools with ER collets gets old fast. I more than once trashed a tool and/or workpiece forgetting to do so... a toolsetter IMO would be worth planning for.

Hi again, smart people! I was wondering if you could check over my shopping list and make sure I am purchasing everything I need and that everything I am purchasing will work with each other.

• Servos (SST57D3201) (came with the machine; they are quite old, but they should still work)
• Prox Sensors
• 7I96S
• Buck Converter for 7I96S
• PSU
• Stepper Drivers
• Shielded Wire

I have a question about my servos. From the data sheet, it says that each motor is 2 amps per phase. The data sheet doesn’t seem to mention whether or not this is 2A phase RMS or peak current. The stepper drivers I’ve picked out are 2.1 amps peak for the closest dip setting. Is this fine to drive these servos? I just want to make sure I’m not going to burn up my servos.

Yes. you need a separate supply.

You can often use a 12V supply and scale the PWM so that full RPM = 10V
 

Hello,

I've been using the 7i96s potentiometer function to control a DC driver board on my mill, 

I'm replacing that motor with a Chinese servo that requires a 0-10v signal to be driven in speed mode, 

The drive itself does not have a +10v that I can feed the digital pot on the Mesa card 

Would I require a separate 10v power supply to feed the Mesa card digital pot to output the proper signal for the servo drive?

Attached are the wiring diagrams form the servo drive, and the link to the servo kit:

www.omc-stepperonline.com/fr/kit-de-serv...p67-a6-rs750h2a1-m17 

Thanks for your help! 






 
 

"A big machine can kill you."

That's why we have licenses to drive automobiles, and a pretty steep barrier to entry for machine tools of this size

I don't want anyone to get hurt, but if someone does get hurt because they were being stupid, no amount of words or safety meetings will prevent it.

Truth does not depend on being proven.
The truth is the truth even when everyone shouts at you and laughs at you.
That's why I have no intention of proving anything.
But I will tell you something very important.
A CNC machine is not a toy.
Even a small desktop machine can waste your time, spoil expensive material, or injure you.
A big machine can kill you.

rodw wrote:

I don't know why this conversation got down to swap drives and building LinuxCNC from source. None of that is necessar. LinuxCNC only requires 4-8 gb RAM but I think I'd lean towards 8 gb today.
 

The author of topic asked for the latest version of LinuxCNC.
The latest version of LinuxCNC is compiled from latest sources...
Compilation of LinuxCNC is easy, easier than many things you have to do after.
Where see you problem?  

I agree, many things are not neccessary, for example PC computer is not neccessary, and LinuxCNC is not neccessary, you could use GRBL  controolled from smartphone, but this is not the subject of the topic.

Modern Linux needs 2 (two) gigabytes of RAM.
Some programs needs more, but LinuxCNC not belongs to them.
My computer I use to write this post (Ryzen 5 with 16 GB of RAM running Firefox on Debian 13.6 with xfce4) uses now 2 GB of RAM, and believe me, this may be less if less memory is installed.

I see, we are on different levels of using Linux...
For me copying whole partition to other disk is normal and often used procedure. I don't need unwanted dependiences, like system not starts without swap partion leaved on old disk. I not need any swap partition, because Linux can use for swap file placed on any mounted partition, and you can turn on/off swap when you need (swapon/swapoff).
Swap file is correct solution, swap partition is a prayer for troubles...

You may use defaults installation settings, and it should works, but why you deny talk about how do it better?


 

Try using the working 5V power supply with the non working Mesa.

' IF I unplug all of the ports on my lathe board and move it over to my mill, the mill does work and linuxcnc connects'

I assume you are using the same known working Ethernet cable in all cases so you can rule that out. Assuming you have the problematic 7i96s on your bench with only it's ethernet and good 5v power connected, I would probably cycle the power and the IP related jumpers (W4 and W5?) and see if you can get it to ping on any address. Beyond this, you can try using mesaflash with the card type and AUTO to try and scan to locate the card. I've had the EEPROM corrupt on my card once and needed to reflash with 'mesaflash --device 7I96s --write <path_to_firmware>.bit' to get communication working again.

I have been tinkering withit and managed to get the touch probe to work, 
what I think its happening is that QTplasmaC doesent want to run any Gcode or any of the user buttons, because the borders of the windows just turn white I click a button or hit cycle start

is it possible for the machine to jog correctly but not run Gcode?
what could be causing this?