Should I buy a 7i96S card?

Hi everybody,

I'm looking for an advise to by an Mese 7i96S card or not.

This is why the question came up. I'm leaving Window (for good) but I have a desktop CNC machine that is depending on it, sort of...
I've bought new hardware and it is running Debian Trixie (with Xfce) as the primary OS, dual boot for the moment with windows 11.

On my old hardware I have the following line of control to my CNC machine.
Windows -> (usb) --> proprietary controller --> (D25 parallel bus connector) --> power stage --> CNC steppers and switches.
There is some proprietary controller communicating with windows driving the CNC machine through a D25 parallel port compatible connection. A power stage electronics board is driving all steppers on X/Y/Z/A axis (and providing signalling in return.

I want to replace the proprietary controller by an Mesa 7i96S card. But also want to verify that it is a valid option to go for.
The new configuration will be:
Debian trixie (RT kernel) + LinuxCNC -> (ethernet) --> 7i96S controler -> D25 parallel bus connector --> power stage --> CNC steppers and switches.
I have found out that there is a one-to-one match between signals on the 7i96S TB1, TP2 and TB3 connectors and the D25 parallel bus connectors but can not find much information on the actual D25 parallel bus signal levels at the desktop CNC side. I expect then to be in 'normal' ranges for a parallel bus connection.

My questions are:
- Is this a 'standard' way of applying a 7i96S controller card?
- Are the Mesa 7i96S TB1, TB2 and TB3 connections capable of driving a D25 parallel bus?
- Are there any pitfalls that I should be aware of when I follow this path?

Kind regards.

 

If you want a parallel port equivalent interface, a 7I92TF or  7I92TM might
make more sense, as these both have 2x parallel port equivalent interfaces

If you wanted to use a 7I96 or 7I96S, you could use its P1 parallel expansion
to connect to the parallel interfaced device.

The real question however is what is the pinout of the parallel connection
to the drives/switch interfaces. If it's truly parallel port compatible, a 7I92T(F,M) or
7I96(S) will work. If it's some proprietary interface from the USB card to a
custom driver card, they will not.
 

The 7i92TF is the best fit in my situation.

The manufacturer claims the pinout of the parallel connection to the drivers/switch interface is parallel port compatible but does not state signal levels for each pin. Multiple manufactures do supply devices for it. The final test of cause is in trying it with a 7i92T module.

Thanks for the advise.

Kind regards.

While there would be  a bit of re-wiring to use a 7i96s natively, you could end up with a cleaner wiring if you had the room and possibly elimination of some relays etc.
I did help someone do this a long time ago and it was pretty simple. Took  a couple of hours including adding limit switches. Just make a very basic/rough config with pncconf and edit the STEP_SCALE in the ini  file so it is the same as Mach's stepsper value. 

rodw wrote:

While there would be  a bit of re-wiring to use a 7i96s natively, you could end up with a cleaner wiring if you had the room and possibly elimination of some relays etc.
I did help someone do this a long time ago and it was pretty simple. Took  a couple of hours including adding limit switches. Just make a very basic/rough config with pncconf and edit the STEP_SCALE in the ini  file so it is the same as Mach's stepsper value. 

First of all: Thank you very much! 

 It was your youtube channel, Debian Trixie and LinuxCNC, that got me going with LinuxCNC and brought me to the point of looking into a 7i96s.

I know that I can optimise by removing some of the existing electronics. I have considered it but the main argument of not going that road is that it is a table top CNC machine, small, reliable and a complete system. Optimising anything byound the D25 parallel port connector will make that machine no longer compatible with the manufacturer model. When, some time in the future, I want to sell this one I have to undo the changes first.

If there are serious performance issues I still have to option of bypassing the manufacterer hardware (or sell this one and get something else).

Again, thank you for the suggestion.

Kind regards, Andre.