My Ruida 644xs will not home nor move correctly in the X axis

I think I had a power blip that got through the surge protector. Now I am having some strange behavior from my machine.

Symptoms:
1.) Will not home correctly in the X axis. The machine tries to home, but only VERY slowly moves in the opposite direction from the limit switch for about 15s. It will then move VERY VERY slowly in the same direction for another 30s until stopping all together. The HMI shows XY coords of 0,0.
2.) Right arrow button on the controller does not work. If I press any other arrow button, the head will move in the correct direction. If I press the movement buttons inside Lightburn, the head will move in all directions correctly.

I have just replaced the HMI and controller with a brand new board and nothing has changed. I am usually pretty savvy with motion control problems but this one has me stumped.

Machine details: Robotec dual head 1300x900. Ruida 644xs controller. Servo motors.

Any thoughts would be greatly appreciated.

Well, after a lot of confusion myself, #1 is because it’s reading the homing switch as “tripped” all the time. So as it starts to home, it sees it’s already AT the homing switch, aborts the fast-seek, and goes to the slow back-off stage, which in normal operation is like 1/4" before it sees the homing switch untrip so it can proceed to the slow-seek step. But it never untrips, and it forever crawls in the opposite direction waiting for the homing input to untrip.

Display the inputs in the diagnostics menu.

If you replace the head and keypad, then it’s not the buttons. I did notice if its understanding of where it is is all wrong, then it may think it’s at XLimit+ and refuse to jog further. Look at the current X coordinate and then go to Mfg Config, X, and look for “breadth”.

in addition to this, you need to properly configure all of the vendor settings to your specific machine’s needs. The slow movement upon startup is due to improper configuration.

Danny, thanks for the tips. I am moving in the right direction.

I am now homing correctly on both axes. However, the X axis seems to get “stuck” at the limit switch. When it homes to the X axis it finds the reed switch, illuminates the LED, then just stays there. It takes another 30s or so before the controller gives up on the homing. After the controller gives up the carriage will not physically move when pressing the panel buttons despite the panel showing the coordinates moving.

Ok are you sure it’s the limit switch that stopped it? Check and see if you can move the axis by hand despite being turned on

If the axis hits a stop, the drive can sense that and latch in a fault state and unpower the motor until you cycle power to the drive

Also more likely is if ruida sees the ximit+ switch tripped, it will not allow jogging in the x- direction, only x+ and homing jumps to the crawlaway step right from the start and never stops trying to crawl off the switch. This is an easy mistake if you set limitpolarity wrong it reads as tripped any time it’s NOT at the limit

Danny, thanks a ton for the help. It was the limit switch that stopped the carriage but not in the way it was supposed to! :smile: The body of the switch was hitting a part of the carriage and causing the drive to trip just prior to activation of the switch. The momentum of the carriage carried it just a tickle further which was enough to activate the switch.

Excellent observation about the drive tripping. Much appreciated.

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