MaxFrenzy

The gecko 251x has the same specs as the gecko 250x , but the 250x isn’t optically isolated and needs a 30 pin male or female header connection to a breakout board. The 250x’s have been used with shopbot’s sbv300 control card (their ARM based mcu running G2), w/ an interface board that accepts the drivers. It currently is run on their handibot cnc, but have been tested on the desktop and various tester’s diy machines.

The specs are:
Signal Voltage – 3.3-5VDC
Supply Voltage – 15-50VDC
Motor Current – 0-3.5A
Power Dissipation – 1-3W
Motor Inductance – 1-50mH
Input Frequency – 0-250kHz
Step Pulse “0” Time – 2uS
Step Pulse “1” Time – 1uS
Direction Setup (Before step rising edge)- 200nS
Direction Setup (Hold after pulse rising edge) – 200nS

From those specs, I can’t see any reason it wouldn’t work, but the disable driver pin presents an issue if I want to use G2 power management. I think they could just be hooked up to 3.3v and work, but having the motors on all the time is just a waste. Regarding the enable pins on the Due, when $MT expires (motor timeout) are the enable pins pulled high or is this handled in another way? If it is the case, then it sounds like the only issue to deal with is inverting either through motate or through external I can look into motate a bit more to see how I could potentially invert those pins as that would be the best solution. For an external pull-up, can you comment on how that is wired? Ex One end of 2.7k resister to 3.3v due pin, the other to enable….etc.

Thanks

I wanted to update a couple things to post findings. I have a buddy that is running a shopbot control card that is essentially their SAM board for running G2 w/ external gecko 250x drivers, 3.5A steppers, 48v psu. He was having similar issues with his x axis on his microcarve cnc. They weren’t nearly as pronounced as mine but it was at the deceleration point as he moved his x axis back and forth. His settings are relatively modest, similar to mine with jerk values set at either 50 or 100. Here is a video of his YouTube Link

Regarding mine, I tried removing the stepper from the coupler to test without any load and had the same results. The stepper seems to handle the higher speed rates but locks up at slower rates. Doesn’t make much sense to me. I replaced the power supply in the machine as well as swapping out the stepper motor from the x axis with the Y and found the same behavior on the Y axis. Just to test some more, I hooked up an arduino uno to a Tb6560ahq driver that came with the 6040 and ran the motor off an atx power supply @ 24v. While I couldn’t achieve the same top speeds (not enough juice from the atx psu I assume), I didn’t have any issues running the stepper at various speeds. I don’t know what the max speed in mm/min the 6040 CNC 3A steppers with a tinyG v9 TI 8825 2.5A drivers are supposed to be, but the concern is obvious that these higher jog/rapid speeds are fun but cutting is going to happen at lower rates. I’ll write a few macros and try to nail down the exact range where the motor locks up. Any other ideas? Drop down to fb=83.09?

Thanks

Sorry I wasn’t quite thinking clearly. For whatever reason, I wasn’t realizing they are part of the trace and thus filled in w/ solder. So, either 2.54mm pin headers or screw terminals would be fine it seems. As for using a due…good question. I do have one available and that probably is the right route to go. I want to clarify something though. While you can setup the pin assignments however you please w/ motate, for convenience and comparison, would it be fine to just use the gshield configuration even if you have no intention of using a gshield? Since I don’t want to break out any additional pins right now, it seems that would at least give me a common reference point and allow me to compare against the gshield for a little easier setup. Does that sound right?

Thanks

Thanks for the info. That is kind of what I started to assume after getting no where speaking to a variety of people about accessing a board. When I did find one from the main company I’m working with, they only had one beta board and wanted to hang on to it for the meantime. As far as contacting the team at Synthetos, that was actually my first route as the development work that I’m doing is in their interest as well. Unfortunately, I did not receive a response back. I wonder if there is a direct email I could try to communicate with someone if I’m unable to get through with the website contact form. You had mentioned some upcoming boards? Could you elaborate on what/when and from whom those might be coming from? Outside of the DUE for handling G2, does a motion control board exist that has an ATMEL 32-bit arm, drivers, and I/Os? I just liked the idea of having everything in a neat package as the machine I’m using for dev/testing has a combined driver/interface board that’s severely antiquated, probably 10 times the footprint size and slower from a variety of perspectives. Thus, I need to update the drivers anyway and figured I’d try to cover it all with one combined unit.

Thanks!