5i25+7i76 wired pendant help please

24 Oct 2017 20:33 #100758 by Toolman321
Hello I have the I/0 boards 5i25 and 7i76. So far I managed to wire up a stepper drive and get it to move. I’ve no other experience with linuxcnc or Mesa cards.

I recently bought an mpg pendant which is a 100ppr pulse generator with two switches, one for axis select x y z a and one for increments.

I would like to connect the mpg to the 7i76 and make it work but I don’t know how to do that and your help will be much appreciated.

Many thanks
25 Oct 2017 00:20 #100768 by andypugh
You probably want to use an mpg encoder on the 7i76 rather than the spindle encoder. To do that you need to set the 7i76 to mpg mode. This converts some of the GPIO pins to encoder inputs.
Page 18 here: www.mesanet.com/pdf/parallel/7i76man.pdf
Note that these are single-ended encoders, so I think you just ignore the /A and /B pins.
To set the 7i76 to MPG mode change the "loadrt hm2_pci" line in the HAL file to include config="sserial_port_0=20xxxxxx"
(keep anything else that already exists in that config string)
Then you should see hm2_5i35.0.7i76.enc0 and enc1 which should increment as you turn the knob.
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25 Oct 2017 20:04 #100811 by rodw
Once you get it enabled, there is a worked example of a single axis MPG for a 7i76e on my build thread
You just need to add the axis selection switch to this which is not difficult and there is a good example in the MPG docs.
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26 Oct 2017 20:21 #100851 by Toolman321
‘Then you should see hm2_5i35.0.7i76.enc0 and enc1 which should increment as you turn the knob.’

I think I’ve changed to mode 2 and I’ve been back through the pncconf wizard and it all looks the same to me?
Can you tell me where I might see that please? Is it in the Hal file?
Many thanks
26 Oct 2017 20:46 #100855 by andypugh
Yes, you will see it in the HAL. Pncconf has done its job at this point, you are at the hand-customisation stage.
(and pncconf doesn't know about smart serial modes as far as I know, and will in fact revert your config if you run it)

I would now suggest wiring up the pendant ant watching the HAL pins change in Halshow (use the Watch tab, as that updates live). If the wiring is correct you should see the encoder counts change and various things happen on the GPIO.
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26 Oct 2017 20:47 #100856 by rodw
You won't see anything in pnccnonf. Its designed to create a basic config that gets your steppers or servos running.

Everything is in your HAL file as per my example and you have to edit it by hand from here on. There is a LinuxCNC module called Halshow that will show you the status of the pins in real time. It is usually available from a menu option or button in the GUI you are using. Thats what you need to use to see enc1 incrementing.
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11 Jun 2018 19:42 #112214 by Toolman321
I finally read all of the information and now I have all the connectors I need to make the pendant work, however I’ve now changed the machine design slightly and now I’m looking to interface the pendant directly(or indirectly) to the Mesa 5i25, via the 26 pin header (p2 I think).
Is it possible I can use another breakout board on this connector just for the pendant, or would I be best using the redundant paraport on the mb?
My reason for asking this is because I’ve changed enclosures and now I have all the pc hardware in one box including 5i25, and in the other box I have the machine control electronics including the 7i76.
Many thanks
11 Jun 2018 19:51 #112215 by andypugh
If there is space in the pendant you could consider a 7i73 connected to the 7i76 serial expansion port.

But if you want to connect direct to the extra port on the 5i25 you can.
With care you can connect directly (I have done it many times to other FPGA boards)

I have found these convenient for connecting discrete wires to Mesa board headers: uk.rs-online.com/web/c/connectors/pcb-co...searchTerm=M20%20pcb

They don't have a 2 x 13 that is an exact match to the 5i25, but you can cut them down and put more than one in the header side by side, etc. You may not need all the pins anyway.

Note that terminals are extra and need a rather small crimping tool.
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15 Jun 2018 12:59 #112403 by Toolman321
Thanks for the useful information provided here.

Atm I have a 7i76 in p3 of my 5i25, is there any reason why I can’t use a common 5 axis bob plugged into p2?
Pncconf is currently configured for 2x7i76.
Many thanks
15 Jun 2018 14:38 #112406 by andypugh
You can use a cheap Mach3 BoB connected to P2. Breakout cables to connect a back-panel 25-pin D-sub are inexpensive:
If you limit the number of stapgens and smart-serial ports in the config="" part of the HAL file then all those pins will be seen as GPIO. (And you will probably find that there is a handy set of encoder pins available too).
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