Thats the one that can handle SPI speeds, not the cheaper mosfet ones? http://cdn.sparkfun.com/datasheets/...N*MTY5NzA0OTc5NC4yLjEuMTY5NzA1MTMxMC42MC4wLjA. Datasheet says 50mA capable
I think I have fallen foul of that very datasheet previously - I do not believe that the device can source/sink anything like 50mA. If you look at the technical guidance note that's linked to in the datasheet: "3. Driving External Loads with TXB Translators TXB devices were architected for driving high-impedance loads. If the application requires an external pull-up or pull-down resistor (Rpu or Rpd), special consideration must be given to the resistor value. When the output is in a steady high or low dc state, it is exclusively driven by the 4-kΩ impedance buffer. If an external resistor is added as either a pull-up or pull-down, a resistor divider network will be formed with the 4kΩ buffer. If the value of the resistor is too small, the VOH or VOL will be adversely impacted." TL/DR My experience is that they're not capable of [reliably] driving opto isolators on stepper drivers. Something like a 74HCT245 is.
Ok easy to fix Solder failed Need to redo it , fan/case top pressing the solder thank you gentlemen, will come back with the next problem
Hi Peeps, been a while ;-) am doing a conversion of a large old chinese CNC, it has external drivers (with 75v dc) so will be soldering to the pin headers for stp & dir and taking gnd from the 24v (4.5A) power supply that will be running the blackbox (don't think will even need that, as am not using the onboard drivers)... question: as I am not using the onboard drivers, the fan is really needed? I have to solder 4 pairs of cables to the pin header, and would be convenient on top and coming out of the side grill, but the fan is in the way.... (and a curiosity plus, the old installed PCB has marked stp+ and dir+ (connected to drivers), but in the actual drivers it is wired to stp- and dir- (with the +ve sides going to a 5v power supply that only supplies voltage to the signal side of the drivers and the endstops)... the pinheaders I imagine are +ve signal..? Not sure if should leave as is on the driver or change round) thanks for any advice! Andy PD actually could also use the bottom pinheaders, and still pass the cables to the drivers thru the side grill
BlackBox outputs + signals, so if you need pulldowns, you'll need to add inverting buffers (or N-channel mosfets) to do that. Fan is for cooling the onboard drivers, heatsink sits right over the back of the drivers.
Thanks for the quick replay, what do you think would happen if I leave "as-is" (as mentioned, the actual PCB has the driver signal wires connected to stp+ & dir+, and there is nothing connected to stp- & dir- on the actual PCB, but on the driver these signals enter into the stp- & dir-.. only to the +ve side of the power supply) not sure if this may be an issue with these Leadshine drivers being incorrectly labeled these signal pins..? any way I can test with a simple multimeter..? I had understood that step pulses are way too short to measure with a normal multimeter, I would need an oscilloscope..? but dir maybe..? should be gnd one direction and 5v the other, but which way is which! edit.. (FWIW, 5v is down, gnd is up at the moment)... (and stp goes to +2.5v approx when moving the motor)** another curiosity, the Z axis endstop with the actual PCB does not activate, however when jogging up the z-axis always stops a tenth of a mm before activating it (so does not activate)... this was very annoying when trying to locate which endstop cable went there, until pulled off the cover and saw this, and also could then check that the z-stop does actually work when I press it, just not when using the actual jog controller.... **ok, think I understand.. the +5v is the "return" and the signals are -ve with respect to this..? so if black box signals are +ve, I WILL have to change the signals to the +ve side on the driver, and wire the -ve to the gnd on the power supply, correct?
Step - / Dir - = GND Step + / Dir + = signal (logic high) Real leadshine or fakes? Most external drivers allow logic high signalling too. Using logic low is more of a 1980s thing (parallel ports could sink more current than source) but modern drivers should be fine with a 10mA logic high signal on the + pin. Good drivers SHOULD have optocouplers inside. Just lighting up an LED internally. Wrong polarity = no light = no step/dir But if its a questionable driver, wrong wiring could short signal to GND, fry the output pin = dead controller
to resume.. the drivers have stp+ & dir+ wired to +ve powersupply, and -ve signals.. this I will swap so the BB is connected to stp+ & dir+ and the stp- and dir- to gnd on power supply and the fan is not needed if not using the onboard drivers... (however will most likely solder to bottom pinheads in the end) this should work...? thanks Andy
well at the moment the machine has both Y axis drivers to the same signal pin, so I could configure the BB as if dual Y motors, and wire to Y2 only first of all.. if all goes well, can swap to Y1, and add the rest, if that driver dies, swap round and SHOULD work with Y1 Using logic low is more of a 1980s thing (parallel ports could sink more current than source) Effectively, the jog pendant is a parallel port (with USB for the computer to upload)
OK cool, in that case, yes, seperate Y signals. Do note it 3.3v though so check the drivers datasheets - if they'll be happy with 3.3v
Leadshine M860, having trouble finding exactly that info... :-/ plenty about max amps, microsteps, etc, even to use resistor if using 12 or 24v signal, but so far not exactly what the signal voltage is...
https://robu.in/wp-content/uploads/2015/12/MA860H-Digital-Stepper-Motor-Driver-ROBU.IN_.pdf page 4 says 5v - 24v signal .. will have to use a logic level shifter.... where can I get 3.3v from the BB to power the BB side..? and will have to add (or leave the old one) a 5v power supply to power the driver side.. :-( page 8 says 4-5v is high logic level
Beware that most common logic level shifters (this sort of thing) cannot supply enough current to work the opto-isolators in the drive. The drive *may* work directly from 3.3V, but if not, you may have to resort to something like a 74HCT245 bus driver.
3V3 is not exposed on any pins, so easiest might be to solder a wire to the top tab of 1117-33 3.3v Regulator (between the ESP and SD Card) Inverting buffer sinking the low side of the drivers might be a good idea then anyway
Hi Peter, So in the end the client does not want to continue with this install as-is... I suppose partially (at least) my fault for not seeing the power supply label for the drivers is 75V until the actual moment of install, & each driver is at 6A, so I was hoping until that point to use the onboard drivers, but 75V, now this obliges to re-use the actual driver PSU and external drivers, which in turn would require soldering direct to pin headers, and then also having a couple of LLS PCBs dangling from the BB... the client wanted a simple plug and play solution (w/o full screen and with pendant), so having to solder was already a problem, but when also wanted to add the LLS to change the voltage from 3.3 to 5v... anyway, I will be returning the BB and the Interface (wish I could justify keeping them for myself/another project, but cannot at the moment), and I will keep the XYZ probe - where can I get a copy of the macro that the probe uses..? Still not sure what controller will go with now, but for sure the XYZ probe will be useful ;-) I will still be recommending the BB as I see it as a great easy way to convert (almost) any CNC, and have already installed a couple, but so far always using the onboard drivers... if it was for myself (my BB converted CNC is much smaller), I would not hesitate to solder and have LLS, for the ease of use of the Controller software as well Cheers! Andy
yeah, I know that the Control software has the XYZ probe interaction, but as I will be returning the BB x32 and Interface, but not the XYZ probe, I'm not sure yet which hardware I will be using, but it is likely that will not be Control software compatible** So I'd like to (easily) find out the macro gcode for the XYZ probe, so I may incorporate it into whatever controller that end up using... ** a doubt arises... if I get a Grbl based controller, will OpenBuilds Control software be able to interact with it, even thou is not a BB? hadn't though about that, but would be very useful as like the simplicity of Control, it is much easier to work with for me ;-) cheers! Andy
That's a controller dependant question then The probe is just a switch. The question is What does the Macro for your new CONTROLLER need to look like - whats its command set, what moves you want it to do, etc. Read its documentation, its software will have its own way to do things, or its own wizards
Hi everybody! I have a Ox Cnc with a lot of modifications, and now, I want to use external drivers. I’ve got the same steppers of Mohamma393 but nothing happen with the same configuration. @Mohamma393 did you use a high level shifter?
