Power to the driver is directly from the power supply.
Basically my issue is: with the potentiometer turned all the way to max current, I still can't get the stepper to move the rail faster than ~6 cm/s or 6 revolutions/second. I'm in default stepping mode, with 16 microsteps per 1.8 deg. The rail however is specced at 220 mm/s, 22 cm/s, or 22 revolutions/second.
I got this combo because the rail is specced at a rated current of 2 A, the BED can supply 2 A, and a power supply which should be more than capable.
What can I try to get to max speed? Am I missing anything blatantly obvious about my setup? Do i need to change the microstep resolution?
For maximum speed with any stepper, you need a high voltage motor power supply (typically 40V) and for the stepper linked, a current limiting driver capable of at least 2 Ampere/phase continuous.
Contrary to the advertising, the Big Easy Driver unfortunately cannot handle 2 A/winding current. A4988 based drivers like the BED can handle only about 1A/phase without extra cooling.
You will need an industrial stepper driver, like the one Amazon recommends on the product page, or the Pololu 36V4 driver (4A/phase continuous without extra cooling), and a 35-45 Volt motor power supply.
jremington:
For maximum speed with any stepper, you need a high voltage motor power supply (typically 40V) and for the stepper linked, a current limiting driver capable of at least 2 Ampere/phase continuous.
Contrary to the advertising, the Big Easy Driver unfortunately cannot handle 2 A/winding current. A4988 based drivers like the BED can handle only about 1A/phase without extra cooling.
You will need an industrial stepper driver, like the one Amazon recommends on the product page, or the Pololu 36V4 driver (4A/phase continuous without extra cooling), and a 35-45 Volt motor power supply.
I've added heat sinks to both sides of the Big Easy Driver and turned the potentiometer to max, but your saying that the BED's true capacity is just not what is advertised?
Paul_KD7HB:
Did you try individual steps rather than microstepping? If not, why not?
Thanks!
To confirm what you're suggesting--set the microstepping resolution to "Full Step" as listed here on the "Microstep Select Resolution Truth Table": Big Easy Driver Hookup Guide - SparkFun Learn
To confirm what you're suggesting--set the microstepping resolution to "Full Step" as listed here on the "Microstep Select Resolution Truth Table": Big Easy Driver Hookup Guide - SparkFun Learn
Probably, I didn't look. You may also need to accelerate the stepper motor as it can't suddenly go to some maximum speed.
your saying that the BED's true capacity is just not what is advertised?
Correct, and you can easily verify that for yourself.
turned the potentiometer to max
That is NOT the way to set the current limit. See the A4988 data sheet for instructions, taking into account the actual value of the current sense resistor on the BED.
Edit: you may find this video by Pololu helpful, but the actual numbers depend on the current sense resistor.
WKau:
I've added heat sinks to both sides of the Big Easy Driver and turned the potentiometer to max, but your saying that the BED's true capacity is just not what is advertised?
Not unless you force cool it - just because the chip can handle the current doesn't mean it will do so without help. Maximum specifications are usually assuming very good thermal management (think water-cooled heatsink).