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5i25 + 7i76: Axis mixed-up and movement only in one direction

27 Jul 2023 08:26 #276355 by Panowski-San
Hi there, im in the middle of setting up my XYYZ gantry-style router using a setup based on a 5i25 and a 7i76 as a breakout board. i'm running four Nema36 closed loop steppers (www.wantmotor.com/closed-loop-stepper-mo...p-stepper-motor.html) with chinese drivers (manufacturers site is quite useless; see manual here: www.hobbytronics.co.za/Content/external/...S880%20programme.pdf). i guess thats about as generic a setup as can be, right?  

Well ive been struggling since the beginning, first issue was that i mis-wired the encoder inputs from the steppers, luckily GND was in the correct spot, but i figured that the driver got a signal on one of the encoder A/B-pins because the motors were shaking as hell. got that resolved, yay! 

Then next issue i could clear was that i messed up something with the power supply, i feed the four switching supplies for the steppers with 230V, also one 24V supply for Vfield on TB1. Regarding the steppers+drivers+7i76, i double and triple checkd that everything's wired correctly then, but the steppers just didnt react at all when i fed them some pulses via StepConf. I then measured that on the 5V-pins of Step/Dir[0-4] on TB[3-4] there was only a tiny voltage, something like 0.1-ish, far from the supposed 5V. Those 5V logic voltage come from the 5i25, which has a seperate power connection btw. Also i noticed that even when the power to my cabinet was cut, the LED for indicating 24V from Vfield was periodically flashing. Oh well, i then re-did the wiring, bypassing the contactor which i thought was a good idea to dis-/connect the mains power from/to the cabinet. I guess the problem was that i used the Neutral line to break the power connection. Anyway, after re-doing the 230V-connections and properly connecting all neutral and earth wires, the 5V LED on the 7i76 now lights up an the steppers finally *ARE* moving -- great success! :-)

TL;DR - the (two) problems i am now facing is
a) somehow the mapping between my phyiscal drivers and the step/dir-ports on the mesa is messed up. clicking through the pncconf-wizard, i assigned STEP/DIR0 -> X-Stepper, 1->Y0, 2->Z; nothing fancy, for now i wanted to get the motors up and running and worry about dual-Y-axis later. now no matter which axis i select (X, Y or even Z, respectively STEP/DIR0,1,2) - its always the X-axis that moves!
b) to make matters worse, that X-axis is only capable of moving in the same direction :-( 

bonus infos
- on point a) when i enable tandem Y-axis, then STEP/DIR 0+2 are moving together; so i guess the hardware step-generators (at least 2 of them) are okay? 
- i found the following thread -> forum.linuxcnc.org/27-driver-boards/4794...moving-one-direction which mentions that the 5i25 might be bad? i wouldnt be surprised if i fried something given my amateurish handling of the power delivery; but at no time i tripped any breakers or seen any other indication of errors (besides the erratic behaviour of the system altogether).

i am currently at work so i only have access to the machine's HAL + ini files and cannot give detailed info on which software versions are involved. i will attach that info ASAP; but given the fact that i only used tools that come with the stable version of the linuxcnc-iso, i would like to exclude sw-bugs; and from my point of view, i think my setup all-in-all seems fairly standard... 

thanks a lot for your attention! 

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27 Jul 2023 12:09 #276365 by tommylight
Pictures of wiring?
Make a new config, choose XYZ, then choose X, Y and Tandem Y, then Z for the stepgens.
Beware that when set as tandem, jog will not work for Y axis untill homed, so that will also imply having working home switches or Y axis set to "imediate homing".
First test drives and motors, since you already have something moving, plug the rest of the drives to the working connector to check if they all move.
Then we can chase gremlins... :)

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