> For the complete documentation index, see [llms.txt](https://docs.lorric.com/qr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lorric.com/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/troubleshooting/oct-alarm-debug-process.md).

# NPN alarm debug process FP-AS310A

<figure><img src="/files/F2VQ9m5s8y0CECaXAOAJ" alt=""><figcaption></figcaption></figure>

### Environmental and Parameter Verification

1. Verify that the main unit is properly powered.
2. Confirm that the data displayed on the interface matches the communication data.
3. Ensure that the NPN function is enabled and correctly configured (Parameter E02). If E02 is set to Pulse v2, verify the NPN Pulse troubleshooting procedure.
4. Confirm the default NPN state is set to either 'Normally Closed (NC)' or 'Normally Open (NO)' (Parameter E01).
5. Verify that the parameters for Alarm A, B, and C are correctly configured according to operational requirements.
6. Check that all wiring is correctly installed, external power connections are stable, and all unused wires are properly insulated. Also ensure there is no magnetic interference in the surrounding area.

* Using a multimeter in current mode, measure between NPN+ and the positive power terminal to check for current flow when C0 = 1.\
  Alternatively, use voltage mode to measure the potential difference between NPN+ and NPN− when S0 = 1; the value should closely match the supply voltage.\
  If no output is detected on first inspection, re-check the power supply circuit.

### **Results and Actions**

1. If the NPN output and the receiving equipment and programme are functioning correctly, but data anomalies persist, check for other possible causes (e.g., pipe diameter, flow rate).
2. The main unit may be damaged. If another unit is available, perform cross-testing to verify the receiver, data processing programme, and wiring are functioning normally.
3. Record the unit’s serial number, wiring diagram (all connections related to the flow meter), and the make and model of the receiving equipment, and contact the manufacturer.
4. Please verify whether there are any faults in the receiving equipment, data processing programme, or wiring.

{% hint style="info" %}
Users should assess the actual on-site conditions. For detailed troubleshooting, please contact LORRIC for further assistance.
{% endhint %}


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