LED States

LED State Reference Table

The following table shows all possible driver states and their corresponding LED patterns.

Legend

Symbol	Meaning
💡 i	Illuminated (ON)
⚫ e	Extinguished (OFF)
🔴 f	Flashing
n	Not relevant

Complete State Table

State	TEC	Power	TEMP	Laser	Interlock	Description
Power-up delay	n	💡	🔴	🔴	🔴	A power-up delay is running or the driver is waiting for start signal reset
Failure mode (interlock and temperature)	n	💡	🔴	⚫	🔴	The driver detected an interlock and a temperature failure. The laser is disabled
Failure mode (interlock)	n	💡	⚫	⚫	🔴	The driver detected an interlock failure. The temperature sensor is not connected, or the wire is broken. The laser is disabled
Failure mode (temperature)	n	💡	🔴	⚫	⚫	The driver detected an overtemperature failure. The laser is disabled
Laser power-up delay	n	⚫	💡/⚫	🔴	⚫	A power-up delay is running. The driver will start after 5 seconds. The TEMP LED is illuminated if a temperature sensor is connected
Laser enabled	n	💡	💡/⚫	💡	⚫	The laser output is enabled. The TEMP LED is illuminated if a temperature sensor is connected
Waiting for start signal / Laser disabled	n	💡	💡/⚫	⚫	⚫	The laser output is disabled. The driver is waiting for a start signal. The TEMP LED is illuminated if a temperature sensor is connected

Detailed State Descriptions

1. Power-Up Delay

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      🔴 FLASHING
Laser:     🔴 FLASHING
Interlock: 🔴 FLASHING

Meaning:

System is initializing after power-on
All safety checks are being performed
Driver is preparing for operation
OR waiting for start signal reset in Standard Mode

Duration: Typically 5 seconds

Next State:

Laser power-up delay (if conditions met)
Waiting for start signal (Standard Mode)

2. Failure Mode (Both Interlock and Temperature)

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      🔴 FLASHING
Laser:     ⚫ OFF
Interlock: 🔴 FLASHING

Meaning:

BOTH safety systems have triggered
Interlock loop is open
Temperature has exceeded threshold
Laser is completely disabled

Action Required:

Close interlock loop
Allow temperature to drop below hysteresis
Reset start signal (Standard Mode) or wait (ARM Mode)

3. Failure Mode (Interlock Only)

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      ⚫ OFF
Laser:     ⚫ OFF
Interlock: 🔴 FLASHING

Meaning:

Interlock loop is open
Temperature sensor is NOT connected or wire is broken
Laser is disabled

Action Required:

Close interlock loop
Check/connect temperature sensor (if needed)
Reset start signal (Standard Mode) or wait (ARM Mode)

4. Failure Mode (Temperature Only)

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      🔴 FLASHING
Laser:     ⚫ OFF
Interlock: ⚫ OFF

Meaning:

Temperature has exceeded threshold
Interlock is functioning normally
Laser is disabled for thermal protection

Action Required:

Allow laser to cool
Temperature must drop below hysteresis threshold
Reset start signal (Standard Mode) or wait (ARM Mode)

5. Laser Power-Up Delay

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      💡/⚫ (ON if NTC connected)
Laser:     🔴 FLASHING
Interlock: ⚫ OFF

Meaning:

All conditions met for laser operation
5-second safety delay is running
Laser will enable after delay completes
TEMP LED state depends on NTC connection

Duration: 5 seconds

Next State: Laser enabled

6. Laser Enabled (Normal Operation)

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      💡/⚫ (ON if NTC connected)
Laser:     💡 ON
Interlock: ⚫ OFF

Meaning:

✅ Laser driver is ENABLED
✅ All safety conditions met
✅ Ready for modulation
TEMP LED ON indicates temperature monitoring active

Notes:

Laser emission depends on modulation voltage
If modulation <0.3V, laser won’t emit despite being enabled

7. Waiting for Start Signal / Laser Disabled

TEC:       n (not relevant)
Power:     💡 ON
TEMP:      💡/⚫ (ON if NTC connected)
Laser:     ⚫ OFF
Interlock: ⚫ OFF

Meaning:

All safety conditions met
Driver is waiting for start signal (Standard Mode)
OR Modulation voltage below threshold
Laser is disabled

Action Required:

Set start signal (Standard Mode)
OR Increase modulation voltage above threshold

State Transition Diagrams

Normal Startup Sequence

Power Applied
      ↓
Power-Up Delay (All LEDs flash)
      ↓
Laser Power-Up Delay (Laser LED flashes)
      ↓
Laser Enabled (Laser LED solid)

Interlock Failure and Recovery (ARM Mode)

Laser Enabled
      ↓
Interlock Opens
      ↓
Interlock Failure (Interlock LED flashes)
      ↓
Interlock Closes
      ↓
5-Second Delay
      ↓
Laser Enabled

Temperature Failure and Recovery (Standard Mode)

Laser Enabled
      ↓
Temperature Exceeds Threshold
      ↓
Temperature Failure (TEMP LED flashes)
      ↓
Temperature Drops Below Hysteresis
      ↓
TEMP LED Continues Flashing
      ↓
Start Signal RESET
      ↓
TEMP LED Stops Flashing
      ↓
Start Signal SET
      ↓
5-Second Delay
      ↓
Laser Enabled

Troubleshooting by LED Pattern

All LEDs OFF

Problem: No power Solution: Check power supply connection

Power ON, All Others OFF

Problem: Driver not starting Solution: Check mode selection, start signal, and safety conditions

Three LEDs Flashing (Laser, TEMP, Interlock)

Problem: Power interruption while start signal was set Solution: Reset and set start signal again

Interlock LED Flashing

Problem: Interlock loop open Solution: Close all interlock switches

TEMP LED Flashing

Problem: Overtemperature Solution: Allow cooling, check TEC operation

Laser LED ON, No Emission

Problem: Modulation voltage too low Solution: Increase modulation voltage above 0.3V