Mesa 7i76e setup help!

Thats really a PCW question but in the meantime as I said read the docs and it explains it...
linuxcnc.org/docs/html/man/man9/hostmot2.9.html

In the docs at that link it says that the "x" disables those smart serial channels so their pins can be used for GPIO.

I'm sorry to be such a bother, but I've still got a few remaining questions. I know you said read the docs, and I have, but there seems to be only a cursory explanation of what I'm asking about. Here's the relevant line:

""To set the modes for port 0 use, for example sserial_port_0=0120xxxx
A ’0’in the string sets the corresponding port to mode 0, 1 to mode 1, and so on up to mode 9. An "x" in any position disables that channel and makes the corresponding FPGA pins available as GPIO.""

My issue is this I cannot for the life of me find anything useful in either the 7i76 documentation or the 7i92 documentation about which pins are getting used or freed up for GPIO. The only thing that comes close is this line """Software process data modes 1 and 2 allow reading the analog voltage on inputs 0 through 3, in addition to the 32 digital bit inputs.""" I wish there were another software process data mode where I didn't get all the analog input, but did get the encoder data for the MPG wheels.

Anyhow, I've got the MPG wheel "working", but I'm running into a lot of joint following errors. I can see why, but I don't know how to fix the problem. Let's say I've got my step size set at 0.010" because I need to move a large distance and I quickly spin the wheel. Naturally the machine can't keep up because it can't accelerate infinitely fast and I get a following error. How do I disable following errors when using MPG, or what do other people do to solve this problem? I've currently got my FERROR at 0.002" and my MIN_FERROR at 0.001". Do people filter the input so that the machine doesn't get what is effectively step input commands (step being the mathematical term such as "step response" not steps as in stepper motors).

I'm also getting errors with the suggested command of: sserial_port_0=02xxxx, but things work great with sserial_port_0=2xxxxxxx. Not sure why that's the case with my setup which is a 7i76 plugged into P2 of a 7i92.

MPG speed is controlled by a setting in the ini file under the DISPLAY section so you could slow it down there.
When I've had following errors, I've been able to get them to go away by increasing these numbers in the ini file

Try 150% instead

I'm also getting errors with the suggested command of: sserial_port_0=02xxxx, but things work great with sserial_port_0=2xxxxxxx.

That's because sserial_port_0=02xxxx is asking the driver to set the mode of the second sserial channel to "2"
but there is no second sserial channel connected

With most 7I76 firmware the first sserial port is the field I/O section and the second is the RS-422 expansion port on the 7I76

You can determine the sserial port connections (and which GPIO pin they are using) by looking at the .pin file that corresponds
with your firmware (or using the mesaflash --readhmid command line option to the read current loaded firmware pinout)

You should not in general get following errors regardless of what you do with the jog wheel. if you do it suggests
a hal file setup issue of some kind

That said, people often feed the jog wheel output through the ilowpass component so big jog increments are not so jarring

grossman83 wrote: My issue is this I cannot for the life of me find anything useful in either the 7i76 documentation or the 7i92 documentation about which pins are getting used or freed up for GPIO..

With a 7i76E it might not be any pins that are even available externally. It does not affect any pins on the smart-serial cards, just the pair of communications pins on the FPGA card.

With the 7i92 it would be a couple of pins on the DB25 connector, and so wouldn't be much help.

With the cards that have a 50-pin header it might be useful to free up some GPIO pins, but even then the GPIO would generally appear on the RJ45 connector of a 7i44 or similar.

You can figure out which port your smart-serial card is on by the pin names:

hm2_7i92.0.7i76.0.0.... would indicate that the 7i76 smart-serial devices are on port zero channel 0. (where we count from zero).
If you plugged a 7i73 into the expansion port it would appear as hm2_7i92.0.7i73.0.1..... and would be controlled by the second digit in the config string.