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Phone: (575) 437-0698 Fax: (575) 439-5314 |
The SSC3 Stepper Motor Control InterfaceControl 3 stepper motors using 1 serial port
The SSC3 interface circuit board controls three 4-phase unipolar stepper motors simultaneously and independently with commands sent from your computers serial port. Stepper motor motion is performed by the SSC3 interface in the foreground while it receives commands from your computer in the background. All 3 stepper motors can be controlled independently, or you can start or stop any combination of stepper motors synchronously. While one stepper motor is in motion you can be setting up step counts and direction for another stepper motor. Your computer can be busy computing the position coordinates for the next move while the SSC3 interface is positioning motors from previously sent commands.
The hardware that you will need to control 3 stepper motors is the SSC3 interface circuit board, a serial interface cable to connect it to your computer, and power sources for the interface and stepper motors. Example programs are provided to help you get started with your CNC (Computer Numeric Control) and Robotics projects. The example programs include stepper motor exercisers that are written in QuickBasic and Visual Basic for Windows. Figure 1 illustrates how the various components of the SSC3 system are interconnected to the interface circuit board. Only 1 of the 3 stepper motors is shown connected in this illustration.
Figure 1. SSC3 System InterconnectThe SSC3 interface interprets 14 different commands. Three of the commands initialize the interface for full step or half step mode, one or two phase excitation mode, and mechanical limit sense. Nine of the commands control stepper motor motion. One command controls the logic states of 7 general purpose digital outputs and another command reads the logic states of 11 digital inputs. Five of the digital inputs are for general purpose use. Six of the digital inputs can be configured at system initialization for use as stepper motor mechanical limit sense inputs or for use as general purpose digital inputs. If they are initialized as stepper motor mechanical limit sense inputs then the stepper motor will stop immediately whenever a limit is reached. A command that reads the stepper status word can be used to determine if a stepper is stopped or running, or if it has reached a mechanical limit. The SSC3 Interface Technical Manual explains all of the commands in detail and provides a listing of a simple QuickBasic stepper motor exerciser program that illustrates how easy it is to command and control 3 stepper motors with the system.
The SSC3 interface circuit board4-Phase Unipolar 4.0 Amp (3 Axis)
Circuit board dimensions: 6.0" x 5.5" x .75".
SSC3 Interface Technical SpecificationsGeneral Operation
Electrical
The SSC3 stepper motor control system is a low cost solution for controlling stepper motors. The SSC3 system only works with 4-phase unipolar stepper motors. Some Stepper motors are designed to function with either 4-phase unipolar or 2-phase bipolar drive control circuitry. These motors have 8 wires. When they are connected properly they will work with the SSC3 stepper motor control system. Stepper motors can be connected to the SSC3 system as simple as illustrated in the system interconnect diagram of figure 1. However, motor torque will only be sufficient at slow speeds. The SSC3 drive circuitry is intended to be used with a current limiting ballast resistor in series with the motor power supply positive output and the V+ terminal on the SSC3 interface circuit board. The motor power supply output voltage should be at least twice the motor coil voltage rating for good motor performance. The current limiting power resistor needed in series with the power supply is determined using ohms law. The voltage drop across the current limiting resistor will be the power supply output voltage minus the motor coils rated voltage. The SSC3 Interface Technical Manual explains the power supply and motor configuration in detail. The program examples disk can be sent as an e-mail attachment free of charge upon request.
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mailto:eee@tularosa.net Phone: (575) 437-0698Copyright © 2008 Eggert Electronics Engineering. All rights reserved. 125 Pasa Por Aqui Lane, Alamogordo, NM 88310 (575) 437-0698 |
