How to diagnose potential issues with a 7i37TA daughter card

Hi all, it has been a while since I've posted here. I did a few Anilam mill conversions with Mesa hardware a while back that are still in active use. The hackerspace I volunteer at is taking on another conversion, this time a large router 6'x10' or so. We're using a Mesa 7i93 with dual 7i40 servo drivers. We've got the 7i93 and the two 7i40 cards working properly, and can for instance get encoder input on all four axes (we have not tried to drive all four motors yet). The 7i40 cards are really fantastic.

Unfortunately, we can not get GPIO working with our 7i37TA. The state of inputs never changes and I cannot drive outputs. We've used pncconf to create a configuration using the search and replace method documented at forum.linuxcnc.org/9-installing-linuxcnc...7i37-easiest-install to assign encoders and pwms to axes, as well as configure GPIO.

With respect to the GPIO, if I just, for instance, short pins one and two on the far end of the 50 pin ribbon connector going to the 7i37TA, I can see the input change in halmeter. Similarly, I can assign an output pin to something like coolant flood and I can see voltage on the 50-pin connector change from 0 to ~5V. This makes me think that the software is doing the right thing, and that the 7i93 and ribbon cable are all fine and that there might be an issue with the 7i37TA. It is brand new out of the box and only has one jumper. I've tried powering it both from the cable and independently, with the jumper set correctly for either case. Unfortunately I get the same behavior. My expectation is I could simply put a jumper wire between, for instance IN0+and IN0- on the 7i37TA and that should get translated to a corresponding change in LinuxCNC.

Is anyone familiar with how to diagnose a potential issue with a 7i37TA? I've been through the product manual, but for instance I don't know if there should be any LEDs lit when it is powered?

As an aside, is I am wondering if there is a way to see the pinout for the 7i93 when LinuxCNC is active. I can see the default for the firmware when LinuxCNC is not running via mesaflash, and I have been able to switch firmwares via mesaflash, but where I would normally see output in dmesg I am not seeing anything. When loading the hm2_eth driver I am configuring 4 pwms and 4 encoders and 0 stepgens, and that is the behavior I see in practice, but I would like to confirm that if possible.

Thanks much!

Scott

The 7I37TA inputs need to be powered, that is you must supply +4v to +24V to INX+ relative to INX- to activate an input
There are no LEDs on in normal operation though there are red LEDs used as back bias protection diodes on the optocoupler
inputs (so if you connect an input backwards you will get a red LED illuminated)

In the userspace version of LinuxCNC, messages are logged to the console rather than the kernel log, so if you start LinuxCNC from a terminal window, you will see the startup/pinout mesages

Thanks for the advice. I'll take a look at the machine this afternoon, but my recollection was that the inputs were showing up as true by default, which is why I tried shorting them to make them false. I'll try what you suggest and report back.

Thanks again!

The FPGA inputs are true by default and with a 7I37/7I37TA connected they are also
true by default and will go false when you apply 4V to 24V across the 7I37TA IN+,IN- pair.

The outputs are similarly "active low" so typically you set the invert_output attribute
of the 7I37TA output associated GPIO pins so the hal pins become active high
("true" for on)

Thanks, with that information I've confirmed the issues were all mine, in that I did not understand the proper behavior. Input and output are both working fine now, and this issue is resolved.

Thanks!

Scott