LED Description

LED Indicator Array

The LED array shows the current state of the driver and all implemented failure states. Every LED has their own states, which are shown by:

💡 Illuminated (ON)
⚫ Extinguished (OFF)
🔴 Flashing

Individual LED Functions

TEC LED

State	Description
⚫ OFF	No TEC board mounted / TEC is not cooling
💡 ON	TEC is cooling

Purpose: Indicates active TEC (Thermoelectric Cooler) operation

Notes:

Only functional when TEC controller board is installed
LED is OFF when TEC controller is not present
LED ON indicates active temperature regulation

Power LED

State	Description
⚫ OFF	Power supply not connected
💡 ON	Power supply connected

Purpose: Indicates presence of supply voltage

Notes:

First LED to check during troubleshooting
Should be ON whenever power is connected
Remains ON during all operating modes

TEMP LED

State	Description
⚫ OFF	No temperature sensor connected / Wire break detected
💡 ON	Temperature sensor connected and temperature below threshold
🔴 FLASHING	Temperature exceeded threshold value - Temperature failure

Purpose: Indicates temperature sensor status and thermal shutdown

Notes:

OFF indicates missing or disconnected NTC sensor
Flashing indicates overtemperature condition
Temperature must drop below hysteresis before flashing stops

Laser LED

State	Description
⚫ OFF	Laser is disabled
💡 ON	Laser is enabled
🔴 FLASHING	Power-up delay is running

Purpose: Indicates laser output enable status

Notes:

ON means driver is enabled (laser may or may not emit depending on modulation)
OFF means driver is disabled (laser cannot emit)
Flashing indicates waiting period before enable

Interlock LED

State	Description
⚫ OFF	Interlock loop is intact (normal operation)
🔴 FLASHING	Interlock loop opened - Interlock failure

Purpose: Indicates interlock system status

Notes:

OFF is normal during operation
Flashing indicates safety interlock has been triggered
Interlock loop must be closed and conditions reset to clear

Quick Reference

┌─────────┬────────┬──────┬───────┬───────────┐
│   TEC   │ Power  │ TEMP │ Laser │ Interlock │
├─────────┼────────┼──────┼───────┼───────────┤
│ ⚫/💡    │  💡    │ ⚫/💡  │  ⚫/💡  │    ⚫      │ Normal States
│         │        │      │  🔴   │    🔴     │ Flashing States
└─────────┴────────┴──────┴───────┴───────────┘

LED Symbols Used

Symbol	Meaning
⚫	OFF (extinguished)
💡	ON (illuminated)
🔴	FLASHING
n	Not relevant

Understanding LED Patterns

Normal Operation Pattern

For typical operation with temperature sensor:

TEC:       💡 (if TEC board installed)
Power:     💡
TEMP:      💡
Laser:     💡
Interlock: ⚫

Startup Pattern

During 5-second power-up delay:

TEC:       varies
Power:     💡
TEMP:      💡/⚫
Laser:     🔴
Interlock: 🔴

Temperature Failure Pattern

When overtemperature occurs:

TEC:       varies
Power:     💡
TEMP:      🔴
Laser:     ⚫
Interlock: ⚫

Interlock Failure Pattern

When interlock opens:

TEC:       varies
Power:     💡
TEMP:      💡/⚫
Laser:     ⚫
Interlock: 🔴

Multiple Failure Pattern

When both interlock and temperature fail:

TEC:       varies
Power:     💡
TEMP:      🔴
Laser:     ⚫
Interlock: 🔴

LED Diagnostic Tips

Power LED Check

If Power LED is OFF → Check power supply
If all other LEDs are OFF → Power supply issue

TEMP LED Check

If TEMP LED is OFF (unexpectedly) → Check NTC connection
If TEMP LED is flashing → Check laser temperature

Laser LED Check

If Laser LED is flashing continuously → Check start signal
If Laser LED is ON but no emission → Check modulation voltage

Interlock LED Check

If Interlock LED is flashing → Check interlock loop continuity
If flashing persists → Check all safety switches

Flash Rate

All flashing LEDs use the same flash rate:

ON time: ~0.5 seconds
OFF time: ~0.5 seconds
Frequency: ~1 Hz

This consistent flash rate makes it easy to identify failure conditions at a glance.