6i25 (5i25) + 7i85s + 7i85s PNCconf problems and questions

Stephanisk wrote: Just a long long steep learning curve and the biggest problem is, reading the manual without an exact working example next to it makes it really hard to memorize and even harder to understand. It's as studying human biology without ever having seen a human body.

I'm just an unemployed road laborer without a 6i25 card to play with. Just a matter of reading the manual and taking a single step at a time. But then again it's so easy to misinterpret something, we've all done it.

I figure if a boofhead like me can understand it anyone can :laugh:

I wouldn't start doubting yourself, it seems like you've been going at it a while, best thing to do is to walk away from it and occupy your mind with another task and come back to it fresh. Usually it'll take 2 seconds you'll see the problem and slap yourself on the head.

Hi all,

Special thanks to ozzyrob and andypugh for a start!

Just got back from holiday. Switched the jumpers... Looked at it with fresh eyes as Ozzy suggested. Managed to find out I was working on the wrong port and I was counting the pins from the wrong direction. So my wires on the 7i85s where not on the correct pins.

I managed to get the driver and motor basically to work. Now comes the rest. More difficult questions will follow soon

But once again, thx all for your help so far. I got it running, that's a hugh part for me in starting to understand.

So my first three question are..

1. Can I get a stepgen type5 working on the 7i85s? Here come my previous driver into play uln2003... 6motors need to be connected. 4 wires each.

2. Can I get microservo motors running on 7i85s? Only 3 wires come out of these motors. +Vcc, ground and signal. (6motors)

If not what Mesa boards would I be looking for, so I can order them.

3. I have 8 step dirs on this 7i85s. And 8 encoders which is great but I would like to have free gpio pins to connect all limit switches seperatly. Is this possible on these cards, can I free up the gpio from the step dir and encoders if not used or are they preset anyhow.

Thanks

On question #3, that is where I used a 7i84. I will connect to one of the 7I85s boards via sserial (smart serial). you can interconnect tehm with a cat-6 cable with an rj45 connector on one end.
Lots of GPIO pins available!


Ray

Stephanisk wrote: 1. Can I get a stepgen type5 working on the 7i85s? Here come my previous driver into play uln2003... 6motors need to be connected. 4 wires each.

Not using the bitfile that you have, no. The issue is that if you look at the VHD file (or the mesaflash --readhmid output, or the dmesg print) each stepgen only has two pins allocated to it. (step and dir) and stepgen type 5 needs 4 pins.
linuxcnc.org/docs/2.7/html/man/man9/hostmot2.9.html#stepgen
If you look at this VHD file you will see what a multi-pin stepgen loooks like:
github.com/LinuxCNC/hostmot2-firmware/bl.../src/PIN_ST12_72.vhd
(That one uses numbers for the pin functions, corresponding to
github.com/LinuxCNC/linuxcnc/blob/master...hostmot2/pins.c#L126
(The "8" means "Output"))

But: I would suggest not bothering. A ULN2003-based driver can only ever run stepers in unipolar mode, and more critically can not (typically) run in constant-current mode. Much better drivers are available very cheaply.

Can I get microservo motors running on 7i85s? Only 3 wires come out of these motors. +Vcc, ground and signal. (6motors)

The type used on model aircraft? Yes, that can be done with a suitably-scaled PWM signal. It doesn't work especially well with software PWM but the Mesa PWM should be OK.

3. I have 8 step dirs on this 7i85s. And 8 encoders which is great but I would like to have free gpio pins to connect all limit switches seperatly. Is this possible on these cards, can I free up the gpio from the step dir and encoders if not used or are they preset anyhow.

You can free them up. If your loadrt hm2_pci line contains "num_encoders=6" then the input pins for the last 2 encoders become available as GPIO. I think this is only 3 actual IO pins, though, due to the multiplexing.

On the 5i25 side these pins can be set to input or output, but the 7i85 enforces a pin direction just through the hardware.

A simpler approach, and one that will give you a lot more IO would be to attach a smart-serial card to the smart-serial port on one or both 7i85 cards. You can connect any two of these to your existing hardware.
store.mesanet.com/index.php?route=product/category&path=83_88

Ok.

I will be ordering a 7184 mode 3 from mesa for my extra inputs and outputs. This is configurable in the pncconf aswell so i see. Thanks for the help.

@andypugh:

Thanks for the explanation, i have looked at all the links.

Would you happen to know which mesa card is usable for which type of the motors. I understand the unipolar mode but these are small projects i need to make to learn operation and secondly to write PostProcessors for real machines. These small prototypes i can use here in my office.

I attached a picture of the micro motors i want to be using.

Which board for the MG90S micro servo? ( 6-7motors)
Which board for the ULN2003A with 28BYJ-48 motor (6-7 motors)? ( i found the vhd, but i can not find a corresponding card.)

Thanks,
Stephane