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iLD Driver

Passive Interlock Systems

Overview

Section titled “Overview”

The driver generates a low voltage signal for passive interlock systems. In these systems, the interlock loop is realized with ordinary breaker switches.

Safety Shutdown Triggers

Section titled “Safety Shutdown Triggers”

The driver monitors two parameters which trigger the shutdown event:

  1. Interlock loop status
  2. Operating temperature

Passive Interlock Configuration

Section titled “Passive Interlock Configuration”

Basic Setup

Section titled “Basic Setup”

The passive interlock system uses:

  • Driver-generated low voltage signal
  • Mechanical breaker switches
  • Series-connected safety switches

Connection Scheme

Section titled “Connection Scheme”
Driver IL+ ───┬─── Switch 1 ───┬─── Switch 2 ───┬─── Switch N ───┬─── Driver IL-
              │                │                │                │
           (Door)          (Cover)         (Emergency)       (Panel)

Wiring Instructions

Section titled “Wiring Instructions”

  1. Multiple Switches in Series

    • Connect all breaker switches in series
    • This creates a single continuous loop
    • Opening ANY switch will break the loop and disable the laser

  2. Connection to Driver

    • Connect one end of the loop to IL+ (Interlock Positive)
    • Connect the other end to IL- (Interlock Negative)

  3. Switch Types

    • Door interlock switches
    • Cover safety switches
    • Emergency stop buttons
    • Access panel switches
    • Any normally-closed safety switch

Example Configurations

Section titled “Example Configurations”

Single Switch System

Section titled “Single Switch System”
IL+ ──── [Emergency Stop] ──── IL-

Multiple Safety Switches

Section titled “Multiple Safety Switches”
IL+ ──── [Door] ──── [Cover] ──── [E-Stop] ──── IL-

Room Safety System

Section titled “Room Safety System”
IL+ ──── [Entry Door] ──── [Window Cover] ──── [Safety Panel] ──── [E-Stop] ──── IL-

Important Restrictions

Section titled “Important Restrictions”

Parasitic Current Protection

Section titled “Parasitic Current Protection”

Ensure that:

  • No parasitic current can influence the interlock loop
  • Switches are properly isolated
  • No leakage paths exist
  • Contacts are clean and reliable

Testing the Interlock System

Section titled “Testing the Interlock System”

Functional Test Procedure

Section titled “Functional Test Procedure”
  1. Power up the driver with interlock loop closed
  2. Verify laser operation (laser should be enabled)
  3. Open any switch in the interlock loop
  4. Verify immediate shutdown (laser disables within microseconds)
  5. Check Interlock LED (should be flashing)
  6. Close the switch
  7. Verify recovery (laser enables after 5-second delay in ARM mode)

Regular Maintenance

Section titled “Regular Maintenance”
  • Test all interlock switches monthly
  • Verify proper contact operation
  • Check for mechanical wear
  • Clean contacts if necessary
  • Document test results

Interlock Loop Resistance

Section titled “Interlock Loop Resistance”

The interlock circuit should have:

  • Low resistance when closed (typically <1Ω)
  • High resistance when open (>1MΩ)
  • No intermediate states

Common Issues

Section titled “Common Issues”

Intermittent Failures

Section titled “Intermittent Failures”

Symptom: Laser randomly shuts down Causes:

  • Dirty or corroded switch contacts
  • Loose connections
  • Vibration affecting switches

Solutions:

  • Clean all contacts
  • Tighten all connections
  • Use vibration-resistant switches

False Triggers

Section titled “False Triggers”

Symptom: Interlock triggers without switch opening Causes:

  • Electromagnetic interference
  • Parasitic currents
  • Ground loops

Solutions:

  • Use shielded cable
  • Ensure proper grounding
  • Isolate from noise sources

Best Practices

Section titled “Best Practices”
  1. ✅ Use high-quality safety switches
  2. ✅ Keep interlock wiring short and direct
  3. ✅ Use shielded cable in noisy environments
  4. ✅ Label all interlock switches clearly
  5. ✅ Document the interlock circuit
  6. ✅ Test regularly
  7. ✅ Train operators on interlock function