Vital Systems Motenc-100 and Motenc-LITE

The Vital Systems Motenc-100 and Motenc-LITE are 8- and 4-channel servo control boards. The Motenc-100 provides 8 quadrature encoder counters, 8 analog inputs, 8 analog outputs, 64 (68?) digital inputs, and 32 digital outputs. The Motenc-LITE has only 4 encoder counters, 32 digital inputs and 16 digital outputs, but it still has 8 analog inputs and 8 analog outputs. The driver automatically identifies the installed board and exports the appropriate HAL objects.


loadrt hal_motenc

During loading (or attempted loading) the driver prints some useful debugging messages to the kernel log, which can be viewed with dmesg.

Up to 4 boards may be used in one system.

1. Pins

In the following pins, parameters, and functions, <board> is the board ID. According to the naming conventions the first board should always have an ID of zero. However this driver sets the ID based on a pair of jumpers on the board, so it may be non-zero even if there is only one board.

  • (s32) motenc.<board>.enc-<channel>-count - Encoder position, in counts.

  • (float) motenc.<board>.enc-<channel>-position - Encoder position, in user units.

  • (bit) motenc.<board>.enc-<channel>-index - Current status of index pulse input.

  • (bit) motenc.<board>.enc-<channel>-idx-latch - Driver sets this pin true when it latches an index pulse (enabled by latch-index). Cleared by clearing latch-index.

  • (bit) motenc.<board>.enc-<channel>-latch-index - If this pin is true, the driver will reset the counter on the next index pulse.

  • (bit) motenc.<board>.enc-<channel>-reset-count - If this pin is true, the counter will immediately be reset to zero, and the pin will be cleared.

  • (float) motenc.<board>.dac-<channel>-value - Analog output value for DAC (in user units, see -gain and -offset)

  • (float) motenc.<board>.adc-<channel>-value - Analog input value read by ADC (in user units, see -gain and -offset)

  • (bit) motenc.<board>.in-<channel> - State of digital input pin, see canonical digital input.

  • (bit) motenc.<board>.in-<channel>-not - Inverted state of digital input pin, see canonical digital input.

  • (bit) motenc.<board>.out-<channel> - Value to be written to digital output, seen canonical digital output.

  • (bit) motenc.<board>.estop-in - Dedicated estop input, more details needed.

  • (bit) motenc.<board>.estop-in-not - Inverted state of dedicated estop input.

  • (bit) motenc.<board>.watchdog-reset - Bidirectional, - Set TRUE to reset watchdog once, is automatically cleared.

2. Parameters

  • (float) motenc.<board>.enc-<channel>-scale - The number of counts / user unit (to convert from counts to units).

  • (float) motenc.<board>.dac-<channel>-offset - Sets the DAC offset.

  • (float) motenc.<board>.dac-<channel>-gain - Sets the DAC gain (scaling).

  • (float) motenc.<board>.adc-<channel>-offset - Sets the ADC offset.

  • (float) motenc.<board>.adc-<channel>-gain - Sets the ADC gain (scaling).

  • (bit) motenc.<board>.out-<channel>-invert - Inverts a digital output, see canonical digital output.

  • (u32) motenc.<board>.watchdog-control - Configures the watchdog.
    The value may be a bitwise OR of the following values:

    Bit # Value Meaning



    Timeout is 16ms if set, 8ms if unset





    Watchdog is enabled





    Watchdog is automatically reset by DAC writes (the HAL dac-write function)

Typically, the useful values are 0 (watchdog disabled) or 20 (8ms watchdog enabled, cleared by dac-write).

  • (u32) motenc.<board>.led-view - Maps some of the I/O to onboard LEDs.

3. Functions

  • (funct) motenc.<board>.encoder-read - Reads all encoder counters.

  • (funct) motenc.<board>.adc-read - Reads the analog-to-digital converters.

  • (funct) motenc.<board>.digital-in-read - Reads digital inputs.

  • (funct) motenc.<board>.dac-write - Writes the voltages to the DACs.

  • (funct) motenc.<board>.digital-out-write - Writes digital outputs.

  • (funct) motenc.<board>.misc-update - Updates misc stuff.