The
DigiRout 200 has high torque NEMA 23 Square Frame
Digital Motors available for all axes .
The picture above shows the construction of the motor. The
robust square frame profile allows a larger diameter rotor which along
with the rare earth magnets & high pole count gives 10 in-lb of
torque True brushless wound outside stator
means there are no
brushes that can wear out. These high torque digital motors combine
affordability and performance for the prime movers of the DigiRout.
The Janus Dual Axis DSCStep™ drive is a new design taking
advantage of the
latest DSC (Digital Signal Controller) technology to digitally filter
the step
& direction motion signals for extra smoothness, precisely
control
the motor current with advanced
digital Sine/Cosine Wave PI (Proportional & Integral) control
algorithms, provide stall detection with automatic shutdown,
and with a proven
compact power output stage rated for 36 VDC provide superior motion
control for the DR200. Made in the USA.
The diagram above shows a block diagram of the controller. The step
signal provides a position interrupt to the DSController. The
firmware program of the DSC digitally filters the accumulated position
reference and calculates the sin/cosine references. The PI
(Proportional & Integral)controllers read the A/D (Analog to
Digital) data provided by the coil current sense circuits at a rate of
25 Khz (25,000 times per second). A calculated PWM (Pulse Width
Modulated) signal is then output to each coil's Mosfet Power stage
providing an averaged voltage output. The reference filtering and
feedback current control provides smooth motion to the motors.
More sophisticated
than microstepping, DSCStep (Digital Signal Controller Stepping)
provides superior motion movement to the DR200. An bonus feature of the
method is that future enhancements to the control algorithm are
field upgradeable. The present version of the firmware provides for
stall detection and automatic shutdown (useful for the dual motor drive
of the DR200 Y axis to prevent racking and binding if one motor stalls
out). Future enhancements will provide anti-stall current contro
techniques. The advanced DSCStep™ filtering smooths the choppy step
& direction
signals controlling the motor current to a true Sine wave for smooth motion.
With this method the motor operates as a high pole count AC
Brushless motor. The above diagram shows actual data transmitted by a running drive via a serial port to a PC.
Here is a video showing the smoothness and speed of the Janus DSCStep Dual Axis
Drives: JanusAxisDrives.wmv Specs
for the X Y Z axes motor:
