Regeneration Current Limiting, Off | RoboteQ AX2550, AX1500 guide

General Operation

Vbat

On

Motor

Off

FIGURE 17. Current flow during operation

On	Off
	I mot
	Avg
	I bat
	Avg

FIGURE 18. Instant and average current waveforms

The relation between Battery Current and Motor current is given in the formula below:

Motor Current = Battery Current / PWM Ratio

Example: If the controller reports 10A of battery current while at 10% PWM, the current in the motor is 10 / 0.1 = 100A.

Important Warning

Do not connect a motor that is rated at a higher current than the controller. While the battery current will never exceed the preset Amps limit, that limit may be reached at a PWM cycle lower than 100% resulting in a higher and potentially unsafe level through the motor and the controller.

Regeneration Current Limiting

The AX1500’s current sensor is capable of measuring current in the reverse flow (regener- ation). Using this capability, the controller will automatically relax the braking effect of the power output stage to keep the regeneration current within safe values. Because of the controller’s high current handling capabilities, this protection mechanism activates only when abrupt deceleration are applied to high-inertia, ultra-low impedance motors.

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AX1500 Motor Controller User’s Manual

Version 1.9b. June 1, 2007

Image 44

RoboteQ AX2550, AX1500 user manual Regeneration Current Limiting, Off

Contents

AX1500 Dual Channel Digital Motor Controller AX1500 Motor Controller User’s Manual Date Version Changes Revision HistoryRevision History AX1500 Motor Controller User’s Manual Section Section Section 100 122 144 173 AX1500 Motor Controller User’s Manual Beware of Motor Runaway in Improperly Closed Loop Important SafetyDo not Connect to a RC Radio with a Battery Attached Important Safety Warnings Locating the Connectors AX1500Quick Start What you will need AX1500 Quick Start AX1500 Controller Rear View Connecting to the Batteries and Motors Connecting to the Batteries and Motors Connecting to the 15-pin Connector Signal Pin RC Mode RS232 Mode Analog Mode Connecting the R/C Radio Connecting the R/C Radio Parameter Default Values Letter Powering On the ControllerDefault Controller Configuration Connecting the controller to your PC using Roborun Connecting the controller to your PC using Roborun Obtaining the Controller’s Software Revision Number Exploring further AX1500 Motor Controller Overview Product Description Technical features Technical features Low Power ConsumptionHigh Efficiency Motor Power Outputs Optical Encoder Inputs optional Compact Open Frame PCB Design Advanced Safety FeaturesData Logging Capabilities Power Connections Connecting Power and Motors to the ControllerPower Connections Controller Power Connecting Power and Motors to the Controller Controller Power Mended Off Configuration Controller Powering Schemes Powering the Controller from a single Battery Powering the Controller Using a Main and Backup Battery Controller Powering Schemes Connecting the Motors Powering the AX1500 with a Main and Backup Supply Single Channel Operation Converting the AX1500 to Single Channel Power Fuses Wire Length Limits Electrical Noise Reduction Techniques Power Regeneration ConsiderationsElectrical Noise Reduction Techniques Undervoltage Protection Using the Controller with a Power SupplyOvervoltage Protection Using the Controller with a Power Supply Connecting Power and Motors to the Controller Input Command Modes General OperationBasic Operation Basic Operation Selecting the Motor Control Modes Open Loop, Separate Speed ControlOpen Loop, Mixed Speed Control General Operation Selecting the Motor Control Modes Closed Loop Speed ControlClose Loop Position Control Temperature Max Amps User Selected Current Limit SettingsTemperature-Based Current Limitation Motor Current = Battery Current / PWM ratio Battery Current vs. Motor CurrentBattery Current vs. Motor Current Regeneration Current Limiting Off Programmable Acceleration Programmable Acceleration Command Control Curves Exponentiation Parameter Value Selected Curve Left / Right Tuning AdjustmentLeft / Right Tuning Adjustment Parameter Value Speed Adjustment Emergency Stop using External Switch Activating Brake Release or Separate Motor ExcitationInverted Operation Activating Brake Release or Separate Motor Excitation Special Use of Accessory Digital Inputs Using the Inputs to Activate the Buffered Output AX1500 Connections Connecting Sensors and Actuators to Input/OutputsAX1500 Connections Connecting Sensors and Actuators to Input/Outputs AX1500’s Inputs and Outputs Signal Type Use Activated AX1500’s Inputs and Outputs Pin1 List and Pin Assignment Connecting devices to Output C Connecting devices to Output C Connecting Switches or Devices to Input E Connecting Switches or Devices to Input F Connecting Switches or Devices to EStop/Invert Input Connecting Switches or Devices to EStop/Invert Input Connecting Position Potentiometers to Analog Inputs Analog Inputs Ana Ana2 Operating Mode Pin Connecting Tachometer to Analog InputsConnecting Tachometer to Analog Inputs Operating Mode Ana 1 p11 Ana2 p10 Ana 3 p12 Ana 4 p8 Connecting External Thermistor to Analog Inputs Connecting External Thermistor to Analog InputsTemp oC Resistance kOhm Using the Analog Inputs to Monitor External Voltages Internal Voltage Monitoring Sensors Connecting User Devices to Analog InputsInternal Heatsink Temperature Sensors Temperature Conversion C Source Code Internal Heatsink Temperature Sensors Connecting Sensors and Actuators to Input/Outputs Optical Incremental Encoders Overview Installing Connecting Using Encoder ModuleOptical Incremental Encoders Overview Installing, Connecting and Using the Encoder Mod Recommended Encoder Types Pulse Frequency in Hz = RPM / 60 * PPR Installing the Encoder ModuleInstalling the Encoder Module Connecting the Encoder Pin Name Cable Color Cable Length and Noise ConsiderationsCable Length and Noise Considerations Voltage Levels, Thresholds and Limit Switches Motor Encoder Polarity Matching Wiring Optional Limit Switches Wiring Optional Limit Switches SW1 SW2 GND Wiring Limit Switches Without Encoders Effect of Limit SwitchesWiring Limit Switches Without Encoders Motor 1 Fwd Motor 1 Rev Motor Fwd Motor Rev Using the Encoder Module to Measure DistanceUsing the Encoder to Measure Speed Using the Encoder to Track Position Using the Encoder to Track Position RS232 Communication with the Encoder Module Distance = Destination Counter value / Divider Encoder Testing and Setting Using the PC Utility Encoder Testing and Setting Using the PC Utility Installing, Connecting and Using the Encoder Mod Closed Loop Position Mode Mode DescriptionSelecting the Position Mode Mode Description Sensor Mounting Closed Loop Position ModePosition Sensor Selection Feedback Potentiometer wiring Feedback Potentiometer wiringFeedback Potentiometer wiring in RC or RS232 Mode Feedback Potentiometer wiring in Analog Mode Pot wiring for RS232 or RC Command and Analog Feedback Analog Feedback on Single Channel Controllers Analog Feedback on Single Channel Controllers Using Optical Encoders in Position Mode Sensor and Motor Polarity Encoder Error Detection and Protection Encoder Error Detection and ProtectionAdding Safety Limit Switches SW1 SW2 Control Loop Description Using Current Limiting as ProtectionUsing Current Limiting as Protection PID tuning in Position Mode PID tuning in Position Mode Closed Loop Position Mode Closed Loop Speed Mode Selecting the Speed Mode Tachometer or Encoder Mounting Tachometer wiringClosed Loop Speed Mode Speed Sensor and Motor Polarity Speed Sensor and Motor Polarity Adjust Offset and Max Speed PID tuning in Speed Mode PID tuning in Speed Mode Closed Loop Speed Mode Normal Fault Condition LED Messages Power On LEDDiagnostic LED Power On LED Output Off / Fault Condition Normal and Fault Condition LED Messages C radio control mode C Operation Selecting the R/C Input Mode Connector I/O Pin Assignment R/C ModePin Input or Number Output Signal Description Operation Input Circuit Description Input Circuit DescriptionSupplied Cable Description Powering the Radio from the controller RC Cable wiring diagram Powering the Radio from the controller Wiring for powering R/C radio from controller Connecting to a Separately Powered Radio Operating the Controller in R/C mode Reception Watchdog Reception Watchdog Transmitter/Receiver Quality Considerations Joystick Deadband Programming Command Control Curves Effect of deadband on joystick position vs. motor speed Joystick Calibration Left/Right Tuning AdjustmentActivating the Accessory Outputs Data Logging in R/C Mode Data Logging in R/C Mode 112 Analog Control and Operation Analog Control and Operation Connector I/O Pin Assignment Analog ModePin Input or Number Signal Output Description Connecting to a Voltage Source Connecting to a Voltage SourceConnecting a Potentiometer Selecting the Potentiometer Value = U/R = 5V / 1000 Ohms = 0.005A = 5mA Analog Deadband Adjustment Analog Deadband Adjustment Data Logging in Analog Mode Power-On SafetyUnder Voltage Safety Data Logging in Analog Mode Modified Analog cable with RS232 output data logging for PC 120 Use and benefits of RS232 Serial RS-232 Controls OperationUse and benefits of RS232 Connector I/O Pin Assignment RS232 Mode Serial RS-232 Controls and Operation Extending the RS232 Cable Cable configurationCable configuration Establishing Manual Communication with a PC Communication SettingsBits/s, 7-bit data, 1 Start bit, 1 Stop bit, Even Parity Roboteq v1.9b 06/01/07 s RS232 Communication with the Encoder ModuleEstablishing Manual Communication with a PC Entering RS232 from R/C or Analog mode Data Logging String in R/C or Analog mode Commands Acknowledge and Error Messages RS-232 Watchdog Controller Commands and QueriesCommand Type Description Controller Commands and Queries Set Motor Command ValueSet Accessory Output Syntax Query Power Applied to MotorsQuery Amps from Battery to each Motor Channel Query Heatsink Temperatures Query Battery VoltagesQuery Analog Inputs ?r or ?R Reset Controller Query Digital Inputs Accessing & Changing Configuration Parameter in Flash Accessing & Changing Configuration Parameter in FlashApply Parameter Changes Read parameter Flash Configuration Parameters List Location Description Active after Input Control Mode Motor Control ModeAddress Access Read/Write Effective After Reset Value Mode See pages Amps Limit Bit Definition See pages Input Switches Function Acceleration Exponentiation on Channel 1 and Channel Address Channel Access Read/Write Effective InstantlyRC Joystick or Analog Deadband Left/Right Adjust Default Encoder Time Base 1 Joystick Min, Max and Center Values Default Encoder Distance DividerDefault PID Gains Reading & Changing Operating Parameters at Runtime Location Function Operating Modes Registers Read/Change PID ValuesBit Function Address 82 P1 83 I1 84 D1 85 P2 PWM Frequency Register Controller Status Register Bit Model or Function Controller Identification RegisterCurrent Amps Limit Registers Read Encoder Counter RS232 Encoder Command SetSet/Reset Encoder Counters and Destination Registers Read Speed Or !Q n Read Speed/Distance Read Encoder Limit Switch StatusRead Distance DD= parameter value Switch ValueRead / Modify Encoder Module Registers and Parameters Address Parameter Description Size Access Switch Status Register DescriptionEncoder Hardware ID code Speed or Distance 1 or Counter Read/Write Mailbox Counter 1Destination Register 1 Register Description Distance 1 Speed 1Time Base 1 Encoder Threshold Decimal Bit Hex Controller Output Counter Read Data FormatCounter Read Data Format 154 Automatic Switching from RS232 to RC Mode Automatic Switching from RS232 to RC Mode Analog and R/C Modes Data Logging String Format Data Logging Cables Dec Hex Decimal to Hexadecimal Conversion TableDecimal to Hexadecimal Conversion Table UDec Hex AX1500 Motor Controller User’s Manual 159 160 System Requirements Using the Roborun Configuration UtilityDownloading and Installing the Utility Connecting the Controller to the PC Using the Roborun Configuration Utility Roborun Frame, Tab and Menu Descriptions Parameter Selection and Setting and Special FunctionsRoborun Frame, Tab and Menu Descriptions File and Program Management Commands View Controller Connector PinoutGetting On-Screen Help Loading, Changing Controller Parameters Control Settings Motor Control ModeInput Command Adjustment Loading, Changing Controller Parameters Power Settings Joystick Timing Analog or R/C Specific SettingsDeadband Encoder Setting and Testing Closed Loop Parameters Encoder Module Parameters Setting Encoder Setting and Testing Viewing Encoder Data Running the MotorsExercising the Motors Motor Power setting Running the MotorsRun/Stop Button Measurement Transmit and Receive Data Real-Time Strip Chart RecorderInput Status and Output Setting Logging Data to Disk Using the Console Connecting a Joystick Using the Console Command EntryTerminal Screen Keep Watchdog Alive Operating the AX1500 over a Wired or Wireless LAN Using the Roborun Configuration Utility Send Reset StringViewing and Logging Data in Analog and R/C Modes Loading and Saving Profiles to Disk Operating the AX1500 over a Wired or Wireless LAN Roboserver screenshot when idle Updating the Controller’s Software Updating the Encoder Software Objectmaker creates controller firmware with custom defaults Creating Customized Object Files 180 Mechanical Dimensions Mechanical SpecificationsMechanical Dimensions Thermal Considerations Mechanical SpecificationsMounting Considerations Attaching the Controller Directly to a Chassis Attaching the Controller Directly to a Chassis Precautions to observe Wire Dimensions Wire DimensionsWeight 186