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Signalling LEDs

Jupiter Servo Drive provides information through 6 signalling LEDs:

  • Supply and operation: 3 LEDs next to the Absolute encoder connector. 
  • CANopen communication: 2 LEDs next to the CAN connector.
  • STO: 1 LED next to the STO connector.

Jupiter with EtherCAT includes 3 more LEDs for the EtherCAT fieldbus status.

Power and operation signalling LEDs

Three LEDs situated next to the Absolute encoder connector indicate the supply and operation status. Next table shows the meaning of each LED:






LED is on when internal power supply is working.



LED is on when a fault or error has occurred.



LED is turned on with the shunt braking resistor is activated, indicating that maximum user voltage has been exceeded and power is being dissipated.

CAN signalling LEDs

Two LEDs besides the CAN connector provide information about the CANopen communication status, according to CiA 303-3 recommendations. The red LED is ERROR LED and green one is RUN LED

ERROR LED indicates the status of the CAN physical layer and errors due to missed CAN messages (sync, guard or heartbeat). Next table the meaning of the ERROR LED states:

ERROR LED state*




No error

Device is in working condition.

Single flash

Warning limit reached

At least one of the error counters of the CAN controller has reached or exceeded the warning level (too many error frames).

Double flash

Error control event

A guard event (NMT-slave or NMT-master) or a heartbeat event (heartbeat consumer) has occurred.

Triple flash

Sync error

The sync message has not been received within the configured communication cycle period time out.



Bus off

The CAN controller is bus off.

RUN LED indicates the status of the CANopen network state machine. Next table shows the meaning of the RUN LED states:

RUN LED state*





The device is switched off



The device is in state PREOPERATIONAL

Single flash


The device is in state STOPPED



The device is in state OPERATIONAL

*See a detailed description of the states in the next table:

* Possible LED states



The LED is always on


The LED is always off

Single flash

One short flash (~200 ms) followed by a long off phase (~1000 ms)

Double flash

Sequence of 2 short flashes (~200 ms), separated by an off phase (~200 ms). The sequence is finished by a long off phase (~1000 ms)

Triple flash

Sequence of 3 short flashes (~200 ms), separated by an off phase (~200 ms). The sequence is finished by a long off phase (~1000 ms)


On and off with a frequency of ~2.5 Hz: ON for ~200 ms followed by off for ~200 ms.

Note that the specified timings can vary in up to ±20%.

STO signalling LED

A LED next to the STO connector indicated the status of the Safe Torque Off system. The states of the STO LED are indicated in the following table:

STO LED state




STO deactivated

The STO is deactivated (STO inputs are energized) and the drive operates normally.


STO activated

The STO is activated (some STO input opened) and the drive power stage is disabled.

EtherCAT signalling LEDs

The Jupiter Servo Drive with EtherCAT fieldbus includes 3 more LEDs to indicate communication status according to EtherCAT specification.

The EtherCAT bicolor green/red LED indicates the EtherCAT state machine status. The green LED is the RUN LED, and the red LED is the ERROR LED. Next table shows their states meaning:

RUN LED state

EtherCAT slave status


EtherCAT slave status

OffINITOffNo error
BlinkingPRE-OPERATIONALBlinkingInvalid configuration
Single FlashSAFE-OPERATIONALSingle flashLocal error
OnOPERATIONALDouble flashWatchdog timeout

OnApplication controller failure

For high severity errors inside the Jupiter Servo Drive, an special LED state has been developed:

StatusSignallingRUN LED stateERROR LED state
Internal errorInterleaved blinkBlinking (Initial status: OFF)Blinking (Initial status: ON)

The frequency of the blinking is different than the used for communication and is product dependent.

The other two LEDs are situated in the EtherCAT connector. Each connector has two LEDs, but only the yellow LED is used. The LINK LED indicates the state of the EtherCAT physical link activity:

LINK LED state

Slave State

OffPort closed
FlickeringPort opened (activity on port)
OnPort opened (no activity on port) 
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