Skip to main content

No Trigger or Output

This page explains how to troubleshoot issues when the OV20i system does not respond to hardware triggers or fails to activate digital outputs.

tip

The fastest way to isolate the issue is to short the Trigger IN wire to GND manually and check for a capture on the HMI.

Common Symptoms​

  • No image capture when sensor or PLC sends trigger
  • Outputs not activating even when inspection passes/fails
  • "Hardware trigger" mode is selected, but no action occurs
  • Output seems to be always low or never pulls down

Step-by-Step Troubleshooting​

1. Switch to Hardware Trigger Mode​

  • Navigate to Image Settings → Acquisition Settings
  • Set Trigger Mode = Hardware
  • Once a trigger signal is received, the camera will automatically capture and the result will appear on the HMI
  • Make sure a project is loaded and active

2. Manually Test the Trigger Circuit​

To rule out camera issues:

  1. Connect Trigger IN (Pin 16, Yellow/Brown) and DIO GND (Pin 5 or 6, Pink/Yellow)
  2. Briefly short Trigger IN to GND
  3. Watch for a capture and result on the HMI

If this works: the camera is functioning correctly — check the external sensor/wiring next.

3. Check Digital I/O Wiring (NPN Logic Only)​

FunctionPin #Wire ColorBehavior
Trigger IN16Yellow/BrownPull to GND to trigger
Digital Output 010VioletSinks to GND when active
Digital Output 111Gray/PinkSinks to GND when active
DIO GND5, 6Pink, YellowMust be tied to system GND

Logic Type: OV20i uses NPN-compatible sinking inputs and outputs

  • Inputs: Activate when pulled to GND
  • Outputs: Pull to GND (active low), require external pull-up to 24 V
  • Max output current: 100 mA

4. Check Sensor Compatibility​

If using an external sensor or PLC, confirm:

  • Sensor output logic is NPN (sinking to GND)
  • If using PNP sensors, you must add a pull-down resistor (~10 kΩ) to GND
  • OV20i and sensor must share common ground (DIO GND)

5. Confirm Output Behavior​

  • Outputs will sink current when active
  • Use a 24 V indicator (LED, relay, etc.) wired like this:
+24 V ---- [Load] ---- OV20i DO (Pin 10 or 11)
                       |
                       +-- DIO GND → System GND
  • If using a relay or high-current device, make sure load < 100 mA or use an interface module

Common Issues & Fixes​

IssueCauseFix
Trigger doesn't workFloating input or wrong wiringShort Pin 16 to GND for manual test
Random capturesInput is floatingAdd pull-down resistor to GND
Output not respondingLoad too heavy or wired incorrectlyCheck current rating, wiring orientation
PNP sensor not workingIncompatible logicUse NPN sensor or add interface circuit
Shared GND missingNo common ground between systemsTie DIO GND to external system ground

Best Practice for Testing​

  1. Load an inspection project
  2. Enable hardware trigger mode
  3. Manually short Trigger IN to GND
  4. Confirm capture is shown on the HMI
  5. Attach sensor and trigger again
  6. Connect output load and verify sinking behavior

Tools & Components​

ToolPurpose
MultimeterMeasure voltage at Trigger IN / DO pins
10kΩ ResistorPull-down for PNP input logic testing
Relay or Load TesterValidate DO output response
Power & DIO CableOfficial camera I/O cable (17-pin M12)

🔗 See Also​