1. Identification and preliminary inspection
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Problem: During the mold closing operation, the machine displays a “Please close door” warning on the screen even though the door is already closed.
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First step: Press the manual button to turn off the fault indicator. Check the safety relay light in the electrical panel. If the relay is not illuminated, the system is experiencing a signal or power supply problem.
2. Inspect and adjust the limit switches.
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Observe the front door limit switch in practice: If the switch is not fully closed, the signal will not be activated.
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Troubleshooting: Adjust the position of the limit switch so that the contacts are fully engaged when the door is closed. In the video, after adjusting the position, the safety relay lit up and the machine operated normally.
3. Check for contact continuity.
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If the relay still doesn’t light up after adjusting its position, you need to remove the limit switch cover to check the internal contacts (usually two normally open contacts are used).
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Measurement method: Use a multimeter in continuity test mode. If flipping the switch does not result in the two pairs of contacts having continuity, the limit switch is faulty and needs to be replaced.
4. Check the safety relay.
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If the signal from the limit switch returns normal but the safety relay still doesn’t light up, you should try replacing it with a different safety relay to test.
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If the problem persists after replacing the relay, users should contact the manufacturer’s technical team for expert support.
This procedure allows operators to quickly resolve common door safety system issues themselves, ensuring the machine can return to production as soon as possible.