PIC STEP V4 - stalling
Is anyone using the PIC STEP v4 driver from Alan, with firmware Std 20 MHz
in the microsteping mode.
I had notice that in this mode all the time the motor is losing steps or you may call stalling.
Vexta motor Pv 267 -- 6 wires/1.4A Bipolar mode/4.8V
35V power supply
I didnt have exactly the same problem,but have troubles with the short pulses of
Mach3 which are configurable from 3 - 25Ás.My optocouplers are too slow to transfer this pulses properly(Masured with Oszilloscope).I used the Optoboard from Dmitri Shilov and PC817 couplers.I think the Opto PCB from Alan seems to be OK.
6 wire to 8 wire stepper - increase torque
6 wire steppers are often unipolar motors.
They have two windings on each pole.
Each winding is phased opposite to the other.
To run a unipolar motor in bipolar mode you use one of the coils on each phase.
If you put an ohm meter across the coils, you often find the power lead is the center of two coils. These coils are wrapped opposite on the pole.
If you open the back of the motor, you can sometimes access the wiring.
Find the center tap and separate the wires to each coil. Leace the original power wire on one coil and cut apart the wire feeding the second coil on the pole. Add a wire to the second coil and bring it out to your wiring harness.
Do this for both poles and you will have an 8 wire motor instead of a 6 wire motor.
You must then phase the coils on each pole to add field and not buck each other. You can do this by wiring the original power wire as power and the added wire as ground. If you wire them in parrallel, the current draw will increase. If you wire the coils in series, the current will stay the same but the voltage will double.
Torque will increase substantually.
You must adjust the power to limit overheating.
I have done this successfully on Slo/Syn motors. The wiring is very easily accessable.
I'm not sure how your motor opens.
Perhaps this will help stop stalling.
Last edited by BCwanderer; 11-13-2005 at 11:42 PM.