Unlimited custom outputs?

I need to setup a machine that will require 200 custom outputs.  I was looking at using Mesa cards since I am familiar with them and they will allow me to control that many outputs using a 7i74 and a bunch of 7i73 cards.  Will LinuxCNC allow that many custom commands?  If so, how would I approach this? I am familiar with the M100-M199 User Defined Commands, is there a way to add more beyond M199?

If you want a lot of TTL level (open drainn) outputs, a 7I90HD in sserial remote mode
will provide 72 outputs (or inputs) per card.

You could use ethercat. Start with a EK1100 coupler
www.beckhoff.com/en-en/products/i-o/ethe...-coupler/ek1100.html
and then add 32 output EL2407 modules as required.
www.beckhoff.com/en-en/products/i-o/ethe...l-output/el2407.html
6 would give you 192 outputs and an  EL2008 rounds it off to exactly 200 inputs.
the EK1100 can supply for 2 amps but the power bus is can handle 10 amps. If you need more power you can insert a EL9410 power supply module between modules on the bus.
www.beckhoff.com/en-au/products/i-o/ethe...x-system/el9410.html

 

How do you want to command your outputs? There are a myriad of ways to control them with in Linuxcnc, custom M-codes being just one. In fact you could command up to 32 outputs with just a single custom M-code with the addition of a binary variable (M100 Pn) where n= an integer number that is written to a hal pin (Bitslice Hal component) who's binary value sets the value of each output pin. You could add another 32 by adding a Q variable to the M-code for a total of 64 outputs with a single M-code command. Now remembering all of your possible binary integer commands to turn on/off the correct outputs might be a bit of a trick, but that shouldn't be hard for a computer to do. I've done this before myself, but for only about 16 outputs.

If a lot of your outputs are related to some sort of logic that "just needs to run in a background program" you can control any or all of them using a custom hal component. There is also classicladder plc logic in LinuxCNC.

with a custom component you could also use an analog digital input. Say you had input numbers 10,20,30.... 
you could use ranges < 15, 15-24, 25-34 etc to decode you input number for a near infinite number of values on one pin and change with m67-m68
eg
M68 E0 Q30   (set relay #30 on)
M68 E0 Q31   (set relay #30 off)

With some creative hal programming, you could probably use arrays so the code would be very compact.

I would like to activate them from g-code.

Why 7i73? I used a Mesa Card Configurator and it showed multiple 7i73's but you are right, the 7i72's would be better.

I would like to use M codes. I had not considered using variables to increase the number of outputs. Is there an example of that available on the forum?

I had posted one of my configs before that uses this for M101, M102, M111, and M112. The commands are for opening and closing a series of fixturing clamps (6 air solenoids) on each side of the machine. M101 and M111 are for closing the work holding clamps (left and right side respectively) in a sequence to help correctly position and hold the parts to be milled.  They use both a P and Q variables (P sets the clamping value and Q an unclamping one.) The clamping sequence can also be changed depending on another parameter variable for different parts. M102 and M112 are primarily for opening the clamps to release the parts and only use the P variable, but depending on the P variable used, can also open or close any array of the clamps immediately without any sequence. All of these M-codes write the appropriate integer value to the appropriate Hal signal name (left-clamp-fl or right-clamp-fl) that then feed the Hal pins that make the magic happen.

Here is a link to the config.
forum.linuxcnc.org/media/kunena/attachments/3190/TwinCNC.zip