DSP-10 - Troubleshooting Guide

No Power LED

Possible Causes

• Incorrect detector model for the installation
• Incorrect wiring
• Insufficient supply voltage
• Failed detector

Troubleshooting

• Verify the correct detector model is installed.
• Confirm wiring is correct.
• Measure input voltage:
  • LV: >10-40VDC, 10-30VAC
  • 117: >100-135 VAC
  • 220: >200-270 VAC

Final Action

• If proper voltage is present and LED remains off, replace the detector.

Power LED Flashes Once Every 2 Seconds

This indicates a problem with the power.

Possible Causes

• Incorrect detector model
• Incorrect wiring
• Insufficient voltage
• Defective detector

Troubleshooting

• Verify correct detector model.
• Confirm wiring is correct.
• Measure applied voltage:
  • LV: >10-40VDC, 10-30VAC
  • 117: >100-135 VAC
  • 220: >200-270 VAC

Final Action

• If voltage is correct and LED continues flashing, replace the detector.

Power LED Flashes Slowly (1 Hz)

This indicates an open loop.

Possible Causes

• Open loop
• High loop resistance
• Excessive loop inductance

Troubleshooting

• Confirm a loop is connected to the correct terminals.
• Disconnect loop and measure resistance:
  • Normal: ≤ 1.5 Ω
  • Fault: > 5 Ω
• Measure loop inductance:
  • Must be < 1500 µH
• If no meters available:
  • Swap loop with a known‑good detector.

Final Action

• If fault follows loop → Repair or replace loop
• If fault stays with detector → Replace detector

Power LED Flashes Quickly (5 Hz)

This indicates a shorted loop.

Possible Causes

• Shorted loop
• Low loop resistance
• Insufficient inductance

Troubleshooting

• Verify loop wiring to correct terminals.
• Disconnect loop:
  • LED should slow to 1 Hz
  • If not → detector faulty
• Measure loop resistance:
  • Normal: 0.5–1.5 Ω
  • Fault: < 0.2 Ω
• Measure inductance:
  • Must be > 20 µH
• Swap loop with known‑good detector if meters unavailable.

Final Action

• Loop fault → Replace loop
• detector fault → Replace detector

Power LED Shows Two Quick Flashes Every 2 Seconds

This indicates a failure but is in working conditions.

Possible Causes

• Intermittent loop fault (open or short)
• Wire fatigue or damaged insulation
• Poor splices or connections

Troubleshooting

• Repair or redo all splices.
• Replace wire nuts with crimp or soldered connections.
• Inspect areas with movement:
  • Expansion joints
  • Conduits
  • Junction box entries
• Look for embedded foreign objects in saw cuts.

Final Action

• If fault persists and cannot be isolated, replace the loop.

Detect LED Intermittently ON / ON With No Vehicle Present

Possible Causes

• Loop insulation failure
• Electrical interference
• Moving metallic objects near loop

Troubleshooting

Loop Integrity

• Perform megger test:
  • Disconnect loop
  • Measure loop‑to‑ground resistance
  • ≥ 100 MΩ = good
  • < 50 MΩ = failed insulation

Electrical Interference

• Adjust loop frequency to avoid cross‑talk.
• Power down suspected interference sources.
• Increase lead‑in wire twisting if needed.

Environmental Causes

• Gates or arms too close to loop (keep ≥ 4 ft).
• Reduce sensitivity one level if needed.
• Secure nearby metal objects (e.g., manhole covers).

Final Action

• Failed insulation → Replace loop
• Unresolved interference → contact Technical Support

Detect LED Will Not Turn ON With Vehicle Present

Possible Causes

• Failed Detect LED
• Sensitivity too low
• Loop or detector fault

Troubleshooting

• Perform lamp test:
  • Toggle DIP switch 1
  • Both LEDs should cycle ON/OFF
• Adjust sensitivity:
  • Typical setting: 5
  • Increase incrementally if needed
• Swap loops with known‑good detector if available.

Final Action

• LED fails lamp test → Replace detector
• Fault follows loop → Replace loop
• Fault remains with detector→ Replace detector