7i92/G540/C10/THCAD

crowloy wrote:

my understanding is that the G540 is not really a great device to use for the encoder due to slow response as well as incompatiblility with the G540 input voltage from what I've been reading. A good reason to switch it over to the C10 on P1. My G540 is an older unit bought when I made my first CNC back in 2015 or so. The C10 is a new style board with surface mount components

So how do you specify an encoder on the P1 port? In your HAL you specify that you have an encoder, but the default is encoder 0 which happens to be on P2. I don't see an option on the loadrt hm2_eth to say you want an encoder on another port or for that matter in hostmot2.

The 7i92 is configured with G540x2 bitfile. The G540 bit is close enough to the C10 i/o that there is not much differance. Also one thing I've noticed and so far have not been able to change is that when linuxcnc is not running, the outputs on P1 seem to be high. I've got a cheap chinese relay board hooked up to the C10 on 2,3,4,5 pins. They are all active until linuxcnc runs and setp's the gpio to output. Only then do they turn off and control of them can occur.

To get access to the second encoder you set "num_encoders=2" in the
hm2_eth command line, the second encoder will be encoder 01

The 7I92 outputs are high at start-up (all pins are inputs at start-up and all inputs have pullup resistors) So its better to arrange for active low inputs if possible or have a common active low output that controls relay power or relay board +5V

Hi all,

i have a similar question, as above. I want to connect a THCAD to my 7i92.
On the 7i92 i run 2 breakoutboards (see below) however i can't figure out what pins  i need to connect the thcad to.
How can i find where the encoder pins are connected to?


www.amazon.nl/DollaTek-5-assige-CNC-brea...rivers/dp/B07PNDXZQK

Thanks!

Unfortunately it would be pretty awkward with those breakouts as the inputs
are slow 12V signals. Even with level shifting I don't know if they could deal
with the ~8KHz signals from the THCAD using the highest divider ratio (128)

The breakout board inputs are activated by grounding so you could try adding
a NPN transistor/small MOSFET to do the level translation from the THCADs ~5V signals
to the 12V required but no guarantees...

A better solution might be to drive the appropriate 7I92 line directly (with maybe a 100 ohm
series resistor for safety)

should i get another bob? and if so what would you recommend?

A CNC4PC C10 (that the OP used) is probably a good choice as its an all 5V BOB.

Great!
just one last silly question: how can i find out to what pins the encoder connects?

i can't find anything about the physical pin numbers in the .ini or .HAL file?
i connected the stepper drivers to wahtever the BOB said and that worked but i feel that this is just luck...
where can i find this?

mesaflash --device 7i92 --addr [card_ip_address] --readhmid

will print the pinout of the currently loaded 7I92 firmware