AVAILABLE YASKAWA ELECTRIC Industrial Servo Motor 3000RPM 0.318N.m SGM-01AW14

 
 
 
OTHER SUPERIOR PRODUCTS

SIMILAR PRODUCTS

Controlling a Stepper Motor
Steppers have been around for a long time. In the old days, stepper motors were actuated by a mechanical switch, a solenoid-driven device that pulsed each of the windings of the motor in the proper sequence. Now, stepper motors are invariably controlled by electronic means. Basic actuation can be accomplished via computer control by pulsing each of the four windings in turn. The computer can’t directly power the motor, so transistors must be added to each winding, as shown in Fig. 19.6.

USING A STEPPER MOTOR CONTROLLER CHIP
In the absence of direct computer control, the easiest way to provide the proper sequence of actuation pulses is to use a custom stepper motor chip, such as the Allegro Microsystems

The basic hookup connection to drive a stepper motor from a computer or other electronic interface. The phasing sequence is provided by software or other means through a port following a four-bit binary sequence: 1010, 0110, 0101, 1001 (reverse the sequence to reverse the motor).

This chip is designed expressly for use with the common unipolar stepper motor and provides a four-step actuation sequence. Stepper motor translator chips tend to be modestly priced, at about $5 to $10, depending on their features and where you buy them. Figure 19.7 (refer to the parts list in Table 19.1) shows a typical schematic of the UCN5804. Heavier duty motors (more than about 1A per phase) can be driven by adding power transistors to the four outputs of the chips, as shown in the manufacturer’s application notes. Note the Direction pin. Pulling this pin high or low reverses the rotation of the motor.