CANBUS Digital Control

The Digital Control feature allows various aspects of the motor controller to be controlled via CANBUS. These include:

• Virtual activation of 'buttons' like REVERSE, IN/OUT, or QUICKSTOP
• Virtual control of Throttle
• Virtual control of the Max Speed Pot

Once configured, the external controller simply sends periodic Digital Control Messages to the motor controller. It is recommended that the messages be sent periodically rather than only upon change, to allow for the possibility of a lost or missed message due to CANBUS noise, etc. A period of 50ms is often used and provides adequate responsiveness for most applications.

Configuring Digital Control Mode

Note that depending on model, the controller may be shipped pre-configured for digital control. This section provides details for users who need to adjust or enable digital control.

Set CAN Control Options

CANBUS Digital Control Options will be set to the desired options. For example, if it is desired that motion is inhibited unless Digital Control messages are being received, set the quickstop and/or zero throttle bits of this item. As a result, unless valid Digital Control messages are being received, the motor will not move an the Reason for Stop indication will include 'Digital Stop Active'

Set Motor Control Options

Configuration Register 0x0357 determines whether Digital Throttle is enabled, and/or Analog Throttle is enabled. Possible values for bits 2:0:

000: Allow Analog Throttle Only

001: Use Analog Throttle, but control buttons (like forward/reverse) using digital CAN messages

101: Use both Analog Throttle and Digital Buttons and Digital Throttle. Depending on the CAN control Options, Digital Throttle may be set to override Analog Throttle. Or, Digital Throttle may be configured to act as a Max Speed Pot (gain value) for the Analog Throttle.

111: Use Digital Throttle and control buttons

Configuration Register 0x031F: If the Digital Pot is to be used as a Max Speed Pot, set bit 6.

Motor Control Commands

Digital Throttle

The Digital throttle is also referred to as the Digital Pot. The Digital Pot command must be sent out every 50msec. When the commands stop the Digital throttle automatically goes to 0. There are several options to stop the motor when commands cease to be sent. See Digital Control Options for information on how to enable or disable throttle shut off and/or quick stop after throttle commands cease to be sent. This function (0x50), is a write only command and no response is returned.

[ ] means optional data. However all data previous to the last value sent must be populated. All missing data fields after the last byte sent are ignored.

NOTE: For dual motor controllers this command only affects the motor associated with the ID used.

Digital Pot

Throttle Value 0-255. This is the same value as Digital Throttle. See Digital Throttle.

The Throttle Value is an 8-bit number that equals the desired throttle setting. 0 is off and 1 or greater can start the motor moving. However, the motor may not shut off if used in conjunction with manual/virtual throttle unless they are set to deadband.

Digital Buttons

NOTE: All bits are set to 1 by default. All features are active low.

Digital Mode

NOTE: All bits are set to 1 by default. All features are active low.

Examples

Set Digital throttle to 25% PWM:

Command:    10EF8090 50 40        0x40 = 64 = 25% PWM       

Set Digital throttle to zero and set buttons to run forward

Command:    10EF8090 50 00 FF     0x00 = 0 = 0% PWM       

Set Digital throttle to 50% and set buttons to run reverse and mode to FF

Command:    10EF8090 50 80 DF FF    0x80 = 128 = 50% PWM       

Refresh CAN Timeout without changing any settings

Command:    10EF8090 50        

Special Diagnostic Commands

Special diagnostic information on motor faults can be found by reading special RAM registers.