1. Log in to the IG502 WEB interface and navigate to the "IO Module → Digital Input" section of DSA;

2. Select the target input channel (e.g., DI1) and check "Enable this channel";

3. Set the signal trigger mode (e.g., "High-level trigger" or "Low-level trigger") to match the output type of the external device;

4. Click "Save" and proceed to the "IO Module → Status Monitoring" section to view the input status (high/low level) of the channel in real time, enabling external switch signal acquisition.