oDCMotor3 Object

The oDCMotor3 Object uses two digital I/O lines to communicate with two motor drivers which in turn handle the voltage and current requirements of the DC Motor.  An optional I/O line controls a mechanical braking device. 

How fast the motor turns and in which direction it turns is controlled by a single value with a range of  -128 to +127.  When this value is 0, the motor is at free-spinning rest.  When the value is a positive number from 1 to 127, the motor turns forward at the speed indicated by the value.  The higher the value, the faster the motor turns.  When the value is a negative number from -1 to -128, the motor turns backwards at the speed indicated by the value.  The lower the number, the faster the motor turns in reverse.

The physical direction that the motor will turn can be configured to:  forward turns clockwise and reverse turns counter-clockwise  or  forward turns counter-clockwise and reverse turns clockwise.

When brakes are activated, the speed value is ignored so that the motor can be stopped. The method used to stop the motor can be either active braking or friction braking.  For friction braking, an output is provided to activate a mechanical braking device.

When the oDCMotor3 object is initialized, it configures the oHBridgeH object to use two drivers by setting the oHBridgeH object's properties. It then sets the oDCMotor3 object's properties as specified in the arguments to the Init method.

The Speed property controls the speed of the motor.  When operating, a 0 in the Speed property will cause the motor to be at a full stop. If the Speed property is greater than 0, then the DC Motor will go forward at a speed specified by the Speed property. The higher the number (up to 127), the faster the motor will turn. If the Speed property is less than 0, then the DC Motor will go backwards at a speed specified by the Speed property. The lower the number (down to negative 128), the faster the motor will turn in reverse.

The actual direction that the DC Motor spins when going in the "forward" direction can be reversed by setting the Invert property.

When the Brake property is set to 1, the I/O line specified by IOLineB is activated and the two drivers are set to the same voltage rail which causes the motor to generate power back into itself, effectively driving itself back the other way which causes it to come to an abrupt stop without the need for mechanical braking.

The Operate property specifies if the motor is on or off.  When the Operate property is set to 1 the two drivers control the motor based on the Speed and Brake properties. When the Operate property is set to 0 the two drivers shut off and the motor stops.

The HBridge property is an instance of the oHBridgeH object which is created when the oDCMotor3 object is.  The oDCMotor3 object configures the oHBridgeH object in such a way that it will provide the proper I/O control for the two drivers and the physical brake.  Attributes of the motor's operation can be adjusted by directly manipulating the oHBridgeH object. Note that doing so may change the way the motor behaves to something different than the way described in this document.  (see oHBridgeH object for more detail)

The maximum number of oDCMotor objects that can be dimensioned in a single application program is 2, limited only be the number of PWM channels available in the ooPIC.

The following table lists the properties of the oDCMotor3 Object:

Property	Description
Speed	A value that specifies how fast and in what direction the motor turns. Object Class:  oPower   Value Range: -128 to +127 Data Type:  Numeric   Default Value:  0 When operating, a 0 in the Speed property will cause the motor to be at a full stop. When the Speed property is greater than 0, the motor will go forward at a speed specified by the magnitude of the Speed property. The higher the number (up to 127), the faster the motor will turn. If the Speed property is less than 0, then the motor to go backwards at a speed specified by the magnitude of the Speed property. The lower the number (down to negative 128), the faster the motor will turn in reverse. Speed Description -128 Full Reverse -96   -64 Half Reverse -32   0 Stopped 32   64 Half Forward 96   127 Full Forward The Speed property is an oPower object which has properties and methods such as SetFullForward and Stop that can also be used to control the speed of the motor.  Examples:  A.Speed =  64  A.Speed.SetFullForward A.Speed.Stop A.Speed++ A.Speed.Value.Dec
IOLineP	A value that specifies which PWM I/O Line is connected to the motor driver's first drive line. Object Class:  oIOLineP   Value Range:  0 - 1 Data Type:  Numeric   Default Value:  0 IOLineP Description 0 The PWM signal is outputted on I/O Line 18.  18 can be assigned to IOLineP in place of 0 but it will read back as 0. 1 The PWM signal is outputted on I/O Line 17.  17 can be assigned to IOLineP in place of 1 but it will read back as 1.
IOLineD	A value that specifies which I/O Line is connected to the motor driver's second drive line. Object Class:  oIOLine   Value Range:  0 - 31 Data Type:  Numeric   Default Value:  0 Some I/O Lines have special purposes.  Be sure to see oIOLine help file for details.
IOLineB	A value that specifies which I/O Line is connected to the braking system's control line. Object Class:  oIOLine   Value Range:  0 - 31 Data Type:  Numeric   Default Value:  0 Some I/O Lines have special purposes.  Be sure to see oIOLine help file for details.
Invert	A value that selects if the physical direction the motor turns is inverted. Object Class:  oSelect0to1L   Value Range:  0 - 1 Data Type:  Numeric   Default Value:  0 Invert Description 0 Motor turns in the direction specified by the Speed property. 1 Motor turns in the direction opposite the one specified by the Speed property.
Brake	A value that selects if the brake is on or off. Object Class:  oSelect0to1L   Value Range:  0 - 1 Data Type:  Numeric   Default Value:  0 When the Brake property is set to 1, the I/O lines specified by the IOLineA and IOLineB properties are set to 0 volts and IOLineP is set to 5 Volts.  Setting the Brake property will cause the motor to generate power back into itself, effectively driving the it back the other way which causes it to come to an abrupt stop without the need for mechanical braking. Brake Brake Output 0 Brakes are off. 1 Brakes are on.
Operate	A value that selects if the motor is on or off. Object Class:  oOperate   Value Range:  0 - 1 Data Type:  Numeric   Default Value:  0 Operate Constant Description 0 cvOff The motor is off. 1 cvOn The motor is on.
Direction	Indicates the direction that the motor is turning. Object Class:  oLogic   Value Range:  0 - 1 Data Type:  Numeric   Default Value:  0 The Direction property is set to 0 if the Speed property is a positive number and set to 1 if the Speed property is a positive number. Direction Direction Output 0 0 Volts 1 5 Volts
HBridge	The I/O function object used to control the Motor Driver. Object Class:  oHBridgeH   Value Range:   Data Type:  Numeric   Default Value:  0 When the oDCMotor3 object is created, it configures its oHBridgeH object to use a dual driver H-Bridge by setting its properties to: HBridge.PWM.Period = 254 HBridge.Option = 1 Attributes of the motor's operation can be adjusted by directly manipulating the oHBridgeH object, but note that doing so may change the way the motor behaves to something different than the way described in this document.
Address	Returns a pointer to the address of the oCounter Object instance. Object Class:  oAddress   Value Range:  0 - 127 Data Type: Pointer (Read Only)   Default Value:  Address of Object

' This program ramps a DC Motor's speed ' up and down / forwards and backwards. Dim A As New oDCMotor3 Sub Main() A.IOLineP = 17 A.IOLine1 = 27 A.IOLine2 = 25 A.Operate = 1 A.Brake = cvOff Do For A = -100 To 100 ooPIC.Delay = 2 Next A For A = 100 To -100 step -1 ooPIC.Delay = 2 Next A Loop End Sub

Bugs: No known bugs.