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4.1 Introduction

The 4 Ampere Stepper Motor Card was designed for controlling bipolar stepper motors operating with currents to 4 ampere. Possible applications are e.g. CNC-machines or robots. Controlling of the card happens over an easy accessible interface e.g. directly by the parallel printer port of a personal computer. The 4 Ampere Stepper Motor Card also supports a wide range of available CNC software packages (e.g. AKKON).

The card is equipped with the well known standard stepper motor controlling circuit L297 from SGS Thomson. The power part is equipped with two drivers L6203 – also from SGS Thomson. For operation the card needs one power supply with 5Volts (for the logic parts) and one power supply for the power part (at maximum 36V). It can either be put in 19” chassis or combined like a sandwich (see picture below).

Figure 4.1 4 Ampere stepper motor card

4.2 Functionality

The 4 Ampere Stepper Motor Card is controlled by five controlling input pins.

Available controlling input pins are:

• Direction input: for controlling the direction of the rotation

• Clock input: input pin for creating the step

• Enable input: for switching the card on or off (if the card is off, no current flows through the drivers)

• Half/Full input: specifying if the card should work in Half step or in Full step mode. In half step mode, the stepper motor is rotating the half angle as to the full step mode

• Imax input: additional input pin for controlling the motor current it the stepper motor is not in movement.

If more than one card is used in parallel, the oscillator clock can be synchronized by using the sync input. This function can be setup up by hardware jumpers, placed on the card. By this way noise can be reduced.

Figure 4.2: Inputs and outputs of the 4 Ampere Stepper Motor Card (principle)

Good setup for the motors and noise can also reduced by the selection of the chopper control. The led indicates if the current selected winding current has the value of IMax or IHold.

The full pin assignment is as follows:

Figure 4.3: Pin assignment of the 4 Ampere Stepper Motor Card

4.3 Signals for controlling a stepper motor card

Figure 4.4: Signals for controlling a stepper motor

Using the 4 Ampere Stepper Motor Card controlling of a stepper motor is very easy. Before the stepper motor goes in operation, it has to be decided if the stepper motor card should work in half or in full step mode. With half step mode, a higher accuracy can be reached by the cost of a small torque. According to figure 4.3 all inputs are set to logical "0". After that the stepper motor card is enabled by setting the enable bit. From now on the holding current flows through the windings of the stepper motor and imply the holding torque of the stepper motor. Next, by settings the direction bit, the direction of the rotation is selected. Before sending clock signals to the stepper motor, the maximum current for movement is set by setting the IMAX-pin. The stepper motor card is now ready for movement. Now, with each clock, the stepper motor rotates on step in the selected direction. Using a stepper motor with a step resolution of 1.8° per step, and 4 clock pulses, the motor would move 4 * 1.8° = 7.2°. If a spindle with a gradient of 5mm per rotation directly coupled to the stepper motor axis is used, the spindle nut would move 7.4°/360° * 5 mm = 0.102mm. The formal relation is shown in figure 4.4.

Figure 4.4 Formal relation between a stepper pulse to the linear movement of a spindle nut.

Figure 4.5 shows the principle how to transform rotation to linear movement using a spindle.

Figure 4.5: Mechanics for the creation of liner movement

An easy control of the 4 Ampere Stepper Motor Card can be realized by using the parallel printer port of a personal computer. The structure is shown in figure 4.6.

Figure 4.6: Direct control of the 4 Ampere Stepper Motor Card over the parallel printer port of a personal computer

4.4 Setup of the 4 Ampere Stepper Motor Card

There are three configurable parameters available for setting up the stepper motor card to the used stepper motors.

These are:

• the maximum current on operation of the stepper motor

• the holing current during operation if the motor does not move

• the delay for automatically setting the holding current

4.5 How to build a 4 Ampere Stepper Motor Card?

In the future, there are two possible variants available:

4.5.1 Variant I: Assembly kit for 4 Ampere Stepper Motor Card

• a printed circuit board of one stepper motor card without parts,

• schematics and layout diagram of parts,

• an easy test program for controlling on 4 Ampere Stepper Motor Card running under Microsoft Windows™ (95, 98, 2000 und XP)

• the source code of the test program written in Borland Delphi Version 7 (professional version)

• a short description how to assemble and setup the 4 Ampere Stepper Motor Card

• all electronic parts for assembling one card

4.5.2 Variant II: Circuit board for 4 Ampere Stepper Motor Card

Your get:

• a printed circuit board of one stepper motor card without parts,

• schematics and layout diagram of parts,

• an easy test program for controlling on 4 Ampere Stepper Motor Card running under Microsoft Windows™ (95, 98, 2000 und XP)

• the source code of the test program written in Borland Delphi Version 7 (professional version)

• a short description how to assemble and setup the 4 Ampere Stepper Motor Card

Schematics etc. for self construction will be provided (probably) soon.

4.6 Specification

• Stepper motor card for 4 ampere (current can variable be set up on the card)

• Mounting dimensions: 100mm * 100 mm, height assembled with parts ca. 30mm

4.7 What do you need for operation? (not included in delivery)

• a power supply (a switching regulated power supply would be very good) with around 5 Ampere and 24-36 Volt

• a small power supply with 5 Volt, 200 mA for the digital control logic

• aA CNC software package (e.g. AKKON)

4.8 What do you need for self assembly?

• Soldering iron

• eElectronic side cutter, tong, small screw driver

• a little bit handy about the house

• Multimeter for checking the assembled printed circuit board and setup of the stepper motor card

4.9 Downloads

File type	Document	Description
	TN001	Description how to setup and configure the 4 Ampere Stepper Motor Card
	Part list	Part list of 4 Ampere Stepper Motor Card
	Schematics	Schematics for 4 Ampere Stepper Motor Card
	Testsoftware	Simple Test Software for parallel port using MS-Windows NT, 2000, XP
	Testkabel	Pin assignment for test cable of 4 Ampere Stepper Motor Card test software