MESA Card Recommendation

Hey guys,

I have put together a design for a machine that I am going to build, and have sorted most of the mechanical aspects.

The main issue I am having at the moment is deciding on software & electronics, there seams to be so many options its hard to find the best option for my needs. I have done a lot of reading on the forum and the wiki pages and have come to the conclusion that a Mesa card is the best solution. I would quite like to run LCNC on a touchscreen laptop, which will be housed in a case similar to the Fanuc or Haas controls. For this reason the ethernet versions of the Mesa cards would be good.

I really like the path-pilot screen but realise its a bit of a pain to install, so will probably get up and running on one of the standard screens and then update if needed later. I want a professional looking interface with the ability to include extra features, (external MPG & physical buttons - cycle start, feed hold, home etc.) and a robust and easy to setup environment. I feel LCNC is perfect for this.

I will be running on stepper motors, (servos would be nice but I am on a budget) and am currently looking at the Mesa 7i76e. Is this the best card to buy, or are there any other options I should look at? I haven't really found anything that compares the many cards that Mesa produce, which is a little confusing sometimes!

If somebody could give me a rundown of the best options for me that would be great! Thank you!

Jack

PathPilot - Ethernet - Mesa = not OK

I wanted to go that route myself but got this message from PCW

AFAIK PathPilot only runs on RTAI so will not currently support our Ethernet cards.
Pathpilot looks nice and has a great conversational interface, _but_ its really made only
to support Tormach products. You will get better support and easier updates if you stay with stock
LinuxCNC (perhaps with one of the newer GUIs)

forum.linuxcnc.org/27-driver-boards/3282...re-rebuilds?start=10

So I decided to go with Gmmocapy to start with.

Cheers
Bengt

I would also appreciate some educated recommendations on selecting Mesa cards... as I have become confused about realtime motion using RS485/Modbus, and also am a bit scared about setting up an ethernet interface card (i.e. 7i76E) which seems to be a bit problematic regarding realtime ethernet kernals etc.

I am a newby on linuxCNC, Mesa cards, and protocols for now, but expect to be up to speed soon, but definitely would appreciate some recommendations to enable me to get started on the right foot.

So, should I:
1) go with the time tested, proven, well documented 5i20 step/dir (but which daughter cards?)
2) go RS485 Modbus (what cards?)
3) go ethernet with 7i76E (but which daughter cards?)

Many thanks for any recommendations.

Regards,
Jono

Machine description: 5-axis Gantry Router (large format, 10kW spindle).
X-Axis: 3kW Servo + 17bit absolute encoder (2 servos). Interface step/dir, & RS-485 Modbus.
Y-axis: 3kW Servo + 17bit absolute encoder. Interface step/dir, & RS-485 Modbus.
Z-Axis: 3kW Servo + 17bit absolute encoder. Interface step/dir, & RS-485 Modbus.
A-axis: 400W Servo + 17bit absolute encoder. Interface step/dir, & RS-485 Modbus.
C-axis: 400W Servo + 17bit absolute encoder. Interface step/dir, & RS-485 Modbus.
Spindle interface: Modbus, digital, analogue ports.
Standard I/Os - coolant, vacuum, pumps, limits, etc,
+ Tool change station (in future) (servo/encoder).
+ Rotary table axis (in future) (servo/encoder).
.... run on LinuxCNC of course...

I would not use a 5I20 except as a replacement for a 5I20 in an existing system
They work but are expensive and old (>10 years)

For a step/dir system I would use either a 7I76E (Ethernet) or 7I76_5I25 (PCI) or 7I76+6I25 (PCIE)

Currently, there is no driver for Modbus via Mesa cards so if you want Modbus spindle control this is done from the host PC (either with a RS-232 --> RS-485 adapter or a USB --> RS-485 adapter)

For a basic system, if you start with a 7I76/7I76E, you probably don't need any additional daughtercards.

Thank you PCW for that information. I have read the manuals for 7i76E, 5i25, 7i76 but have not immediately been able to determine the following:

1) Can the 7i76E run on the LinuxCNC distro? Reading on this forum/site the realtime ethernet setup seems to be problematic/complex? I would prefer standard and straight-forward rather than problematic/complex for my first LinuxCNC project.... The 5i25/7i76 combo seems the better newbie option?

2) 7i76e / 7i76 has only 5-axis step/dir, so therefore my gantry x-axis' two servo interfaces must be connected together off one 7i76 interface? is this standard? Or, do I need to add a second 7i76? I will also need an axis for rotary table.

3) How do I handle my 17 bit encoders on this setup?

Regards
Jono

1. The 7I76E requires a Preempt-RT kernel and the uspace version of LinuxCNC
recently you had to either build from source or install the uspace LinuxCNC package
over the standard LinuxCNC ISO to get this.

In the last couple of days a new LinuxCNC/Debian stretch ISO has been released
which includes a uspace version of LinuxCNC with a Preempt-RT kernel
This will work as is with any of the Mesa Ethernet cards like the 7I76E

2. if you need more than 5 axis, (and you dont need more I/O) you could add a simple breakout like a 7I78

3. Normally in step/dir systems, the encoders connect only to the drives