We are building a machine that consists of the following: BlackBox X32 A gantry that moves along the y-axis, driven by a stepper on each end (timing belt, not lead screw). A carriage on the gantry driven by a stepper. The carriage contains a standard RC servo and a linear actuator that is driven by two GPIO pins that should always be in opposite states. There will (ideally) be limit switches on both ends of both axes. Also: Our intention was to use the dual limit switches on the 'home' side of the Y axis to make sure the two Y axis steppers are in sync (so the gantry doesn't get racked by the two ends not being driven together. Basically when we home we want to see both limit switches hit. Current thought is: Drive X axis like any other normal x axis Drive linear actuator with the double throw relay output Drive servo with servo output I'm confused on how to handle the Y axis, particularly with respect to homing the two steppers individually. Does anyone have any advice on how to do this if it's even possible?
Using AutoSquaring under http://svn.io-engineering.com:8080/?driver=ESP32&board=BlackBox X32 > Y-Axis dropdown > Auto Squared X switch wires to X Limit port Y1 switch wires to Y Limit port Z and Y2's switches wires in parallel to the Z Limit port (Z and Y moves seperate, so putting Y2 on Z allows firmware to check for it during the Y move) docs:blackbox-x32:connect-rc-servo [OpenBuilds Documentation] - note onboard supply limited to around 500mA (meant for these little 9gram servos typically used as pen lifts on a plotter) - if its a big servo rather power externally and use only SIG and GND off the BlackBox to prevent damage to BlackBox Use a stepper based actuator? Would be a lot easier: Linear Actuators - OpenBuilds Part Store
We are. We bought one from y'all. Our gantry is one of your stepper-based linear actuators. The linear actuator on the carriage is a tiny little thing about 5 inches long. None of your linear actuators would ever fit on the carriage. In any case our main problem is how to zero/home both sides of the Y axis.
NEMA17, one of these Nut Plate for 8mm Metric Acme Lead Screw on a short piece of 2040, and a couple Mini V-Wheels? Similar to ACRO 1010 with custom Z axis but can be made more compact if you try Even in the standard actuators you know - you get them in either DC or stepper. The spindle outputs might be able to do external relays (with additional circuitry they only provide logic signals, can't drive coils on a relay directly), but just better to have a stepper based axis if possible (standard Z axis, follows gcode, is in sync, drivers already there just plug it in etc) Or search the forum for Acro Z axis - couple cool ideas around, like Z-Axis for Laser Diode and many more
As an update to this - I've been out of town for three week and just got back to it. My Y2 limit switches trigger an alarm when the gantry backs *away* from them. I know there is a way to invert limit switches but I can't figure out how to do it for just one axis (Y2 is wired into Z limit as @Peter Van Der Walt suggested above). Ideas?
@Peter Van Der Walt, thanks. Sorry to keep peppering you with questions but... Is there a way to have the BlackBox completely disregard the Z axis for homing? Or in there alternative, is there a command to home an axis individually? For all relevant purposes my machine is a 2-axis machine. I DO have the Y2 limit switches wired into Z though, as you suggested. When I try to "home all" I get a "Could not find limit switch within search distance..."
Perfect. That worked. Now another issue... This is getting close though! I thought it was supposed to close the limit switch, then back off and re-approach very very slowly until it closed again...? Instead I get this the instant the switch closes and everything stops. ALARM: 6 - Homing fail. Reset during active homing cycle. [ $H ]
What are your grbl settings, especially $27. This is the pull off distance and it is explained here :- grbl/doc/markdown/settings.md at master · gnea/grbl If you are new to grbl it is worth bookmarking that reference. Alex.
Its not, it literally reset the controller. Looks like a wiring mistake / short shorting V+ to GND when the switch closes. The can damage the Blackbox! Check all wiring against docs docs:blackbox-x32:start [OpenBuilds Documentation] (Sections 3.4.x) or post wiring pics for review
I set that to 10mm. It's not backing off the switch at all. The instant the switch closes it alarms and everything stops.
Peter, you were correct. One of us (almost certain my coworker) incorrectly wired one of the limit switches for the Y2. Inexplicable because both the switches and the BlackBox are clearly marked. In any case, we’ve likely blown the Z Axis limit switch input. For this project I can get away without it but assuming we wanted to try to fix it, could we replace the microcontroller in the BlackBox and burn new firmware into it? Or is it another part that would be damaged? We have full PCB rework capability in-house.
The inputs themselves are hard to damage are you sure? Shorting V+ to GND (causing the reset) is more likely to damage voltage regulator / cause voltage regulator to damage microcontroller. Per the symptoms thats what was wrong. Signal input can tolerate GND to 24V and anything in between, not easy to kill. Arte you testing with the Troubleshooting tab in CONTROL? Maybe still wired wrong, thus not detecting pressing of switch? Or it was wired so wrong the switch PCB burned traces? (Try different switch on Z port)
Hm. Now I'm testing with the troubleshooting tab and the Z Axis seems to work fine (same limit switch). But still getting the problem while homing - it hits the limit switch and throws an alarm. If I disconnect the Y2 limit switch it homes just fine. I do have the "Auto Squared" build burned onto the controller.
Just to rule out the firmware so maybe without Y2 and with squaring firmware vs normal firmware? I believe its more likely wiring unless there are other firmware crash messages in the log
