Help wiring up BLDC drives with BISSC linear encoder to 6i25_7i76_7i74

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2 years 5 months ago #300816 by pmchetan
How can I use GPIO digital output to handle motor direction?
Like PCW said, it could've been simpler with negative and positive analog voltages for both speed and directions but Like I said earlier, I imagined the drive analog output of 7i77 as external pot controlling the BLDC. I tried and it works. The motor spins with the analog out from 7i77 in open loop test in pncconf.

how to set gpio pin to control forward/reverse function for this application. Axis motor direction seems critical so is using signals on servo thread might not be a good idea. What other option do I have?

@ besriworld Again configured as spindle, I need to set F/R somehow.

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2 years 5 months ago #300943 by tommylight

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2 years 5 months ago #300991 by pmchetan
The drive in pulse mode isn't working with 7i76. I tried tune axis during pncconf to let 7i76 talk to the drive and get something on the motor, but I get nothing. Any 7i76 firmware I flash seem to be missing dpll.01.timer-us and stepgen.timer-number I tried MesaCT to flash 5i25_7i76x2, 5i25_7i76_7i74, 5i25_7i76_7i77 as well as I downloaded the bit files from mesa website and flashed using mesaflash 3.4.6 running linuxcnc 2.9.2 on debian 12.

I thought both +5v pin on the 7i76 daughterboard as well as my BLDC drive are +5v out, so I haven't connected them. Is it safe to connect?

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2 years 5 months ago #301060 by pmchetan
Does either 7i76 or 7i77 outputs PWM signal for axis control (3 axes)? pncconf uses the nomeclature axis stepgen during 7i76 and axis PWM during 7i77 configuration.

Like PCW has already mentioned, controlling the speed with sv and separate forward/reverse pin is awkward but I'm willing to go that route if it is at least possible.

 

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controlling through 7i76 with the wiring I began this thread with isn't working. I would like for someone who has dealt with similar hardware to chime in.
Or is completely abandoning the drive and buying an new BLDC drive with step and direction input a better option?

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