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Errors and recovery

When the driver detects a fault it disables the motor, goes to idle, turns the status LED on steadily and sets the error bit in every CAN frame it sends. A disabled motor coasts, also when #Brake 1 is set. The driver stays there until the error is cleared.

Seeing the error

  • The LED: on and not flashing means error mode (or not calibrated). Three short flashes and a pause is normal operation; fast flashing, about 10 times a second, is calibration.
  • #Error prints In error state! or No errors!, followed by one line per active error.
  • Send_Respond_State_of_Errors returns every flag as a bit; the error bit of any frame says whether there is one.
Normal operation Calibration Error mode
Three short flashes and a pause Fast flashing On, steady

In error mode the LED does not flash: it stays on, as in the photo on the right.

The errors

Error #Error line Cause What to do
Vbus Vbus error the supply voltage is below 9 V or above #Vmax (29 V after #Default). From firmware 109 a low voltage is not checked for the first 500 ms after power-up, while the supply ramps up check the supply and the cable; a decelerating motor can push the voltage up
Encoder Encoder error the magnet is not detected or the reading is invalid magnet distance and type, see The encoder magnet
Driver Drv error, and FAULT pin is LOW: the gate driver reports a fault while the fault lasts (firmware 107 and older printed FAULT pin is HIGH) the MOSFET driver's own protection tripped: undervoltage, thermal shutdown or overcurrent lower the current limit, cool the driver, check for a short between the motor leads
Velocity Velocity error the measured speed exceeded 20,000,000 ticks/s (about 1220 revolutions per second), a fixed limit that #Vlimit does not change a runaway or an encoder fault: check the magnet and the encoder, see The encoder magnet
Temperature Temp error the thermistor reads more than #Tlim (75 °C by default) or less than −20 °C, with #Term 1 let the motor cool; lower the current limit
E-stop Received ESTOP command Send_ESTOP was received, or from firmware 110 #Estop over UART clear it when it is safe
Watchdog Watchdog error no motion command or answered request over CAN within the watchdog time (Send_Watchdog); what the motor does then is the watchdog's action, see The watchdog the host stopped sending; fix the host, then clear. See The watchdog
Wrong product Wrong firmware for this board (product lock) from firmware 109: this board was calibrated by the other product (a STEPFOC firmware on a Spectral Micro, or the other way round), so the firmware drives nothing (The product lock) flash the right firmware; it does not clear otherwise
Not calibrated Not calibrated the motor has not been calibrated since #Default, or the EEPROM is invalid run #Cal and #Save
Current Current error reserved; this firmware never raises it —

Clearing

#Clear or Send_Clear_Error clears the flags and goes to idle. An error whose cause is still present comes straight back: a Vbus error at 2 V stays until the supply is right; once the supply is 24 V, one #Clear returns the driver to normal operation.

The calibration error clears only by calibrating (or, for a motor you know is calibrated, #Calibrated 1).

The watchdog

The watchdog is set with Send_Watchdog over CAN, or with parameters 6 (time) and 7 (action): over UART, #Par 6,<ms> and #Par 7,<action>. It counts the motion commands (Send_data_pack_1, Send_data_pack_PD, Send_gripper_data_pack) and the requests the driver answers (the Send_Respond_ remote frames, Send_Get_Parameter, Send_Buffer_Read).

Other CAN frames and UART commands do not reset it. Send_Save_config keeps it over a power cycle, like the heartbeat interval. What the driver does when it runs out is the watchdog's action (The watchdog).

A driver with a saved watchdog that is used over UART only, or by a host that sends no motion command, raises a watchdog error each time the watchdog time runs out, also right after #Clear.

To turn it off, send Send_Watchdog with 0 and then Send_Save_config over CAN. Over UART, #Par 6,0 and then #Save do the same; nothing else is changed.

When the driver does not answer

  • No LED at all: no power. Check DC+ and DC− and the cable orientation.
  • LED on, no answer on UART: the baud rate (256000), TX and RX crossed, the adapter's port.
  • No answer on CAN: the node ID, the termination (about 60 Ω across the bus, unpowered), 1 Mbit/s on the adapter.
  • #Info shows -1 or nonsense: the EEPROM holds values the firmware does not expect, usually from an older release (see Saving the configuration); #Default, then calibrate again.

Troubleshooting goes through the symptoms one by one.

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