Troubleshooting¶
No Display / Meter Not Powering On¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| Blank LCD | No auxiliary power | Check terminals 5-6: verify 85-277V AC present |
| Blank LCD | Blown fuse/breaker | Check circuit protection upstream |
| Dim display | Low voltage | Measure voltage at terminals 5-6 (min 85V AC) |
| Display flickering | Loose connection | Tighten terminal screws on 5-6 |
No Modbus Communication¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| No response from meter | Wrong baud rate | Verify baud rate matches (default: 9600) |
| No response from meter | Wrong address | Verify Modbus address (default: 1) |
| No response from meter | Wrong parity | Set to EVEN (default) |
| Garbled data | RS485 wiring swapped | Swap D+ and D- wires |
| Intermittent communication | Poor grounding | Connect RS485 shield (terminal 11) |
| Bus errors | No termination | Add 120Ω resistor at bus ends for long runs |
Modbus Debugging via Tasmota Console¶
This enables verbose serial logging to see Modbus traffic in the Tasmota console.
Incorrect Readings¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| Zero current reading | CT not connected | Check Rogowski coil cables on terminals 15-20 |
| Zero current reading | CT ratio = 1 | Set CT ratio to match coil rated current |
| Negative power reading | CT reversed | Check coil arrow direction (source → load) |
| High power reading | CT on wrong conductor | Verify CT1→L1, CT2→L2, CT3→L3 |
| Wrong voltage reading | Wrong system type | Verify 3P4W/3P3W/1P2W setting |
| Inaccurate readings | CT ratio mismatch | Match CT ratio to installed coil model |
Reset Energy Counters via Tasmota Web Interface¶
If accumulated energy totals (kWh) are wrong — for example after changing the CT ratio, re-wiring the coils, or moving the meter — clear the stored counters so new readings start from zero:
- Open the Tasmota web UI in a browser:
http://<device-ip>(find the IP from your router or the AP-mode portal). - Click Console.
- Enter the reset command and press Enter:
EnergyReset 3 clears the total energy counter. Use EnergyReset 1 for the
Today total or EnergyReset 2 for the Yesterday total. See
Appendix C: Tasmota Commands for the full
EnergyReset 1-7 range.
- Confirm the console reply shows the counter reset to
0.000, then verify the live values on the Main page.
Note: This clears only the accumulated energy history. It does not change live voltage, current, or power readings — if those are wrong, correct the CT ratio or wiring using the table above first, then reset the counters.
Wi-Fi Connection Issues¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| Cannot connect to Wi-Fi | Wrong credentials | Reset to AP mode (see below) |
| Intermittent disconnection | Weak signal | Check RSSI in console: Status 5 |
| Device not on network | DHCP issue | Set static IP: IPAddress1 192.168.1.x |
| Slow telemetry | Wi-Fi power save | Increase Sleep setting: Sleep 0 (no sleep) |
Reset to AP Mode¶
Method 1 — Via console:
Method 2 — Hardware reset:
- Press and hold the reset button on ESP32-C3 for 10+ seconds
- Device restarts in AP mode with SSID "RS-EMON3P"
MQTT Connection Errors¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| MQTT not connecting | Wrong host/port | Verify broker address and port (1883/8883) |
| TLS handshake failure | Fingerprint mismatch | Update MqttFingerprint1 with current cert |
| TLS handshake failure | Wrong port | TLS requires port 8883, not 1883 |
| Authentication failed | Wrong credentials | Verify MQTT username/password |
| Connection drops | Broker unreachable | Check network path to broker |
Check MQTT Status¶
Shows current MQTT connection state, broker, and topic.
Home Assistant Not Discovering Device¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| No entities in HA | Wrong discovery prefix | Verify SetOption19 0 and Prefix homeassistant |
| No entities in HA | MQTT not connected | Check MQTT connection first |
| Stale entities | Old discovery messages | Restart Tasmota: Restart 1 |
| Duplicate entities | Multiple devices same topic | Verify unique topic per device |
OTA Update Failures¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| Update fails to start | Wrong OTA URL | Verify URL is accessible and HTTPS |
| Update fails mid-way | Unstable Wi-Fi | Ensure stable connection before updating |
| Device unresponsive after update | Corrupted firmware | Flash via serial (recovery mode) |
Rogowski Coil Positioning Issues¶
| Symptom | Possible Cause | Solution |
|---|---|---|
| Intermittent zero readings | Coil not fully closed | Verify latch is clicked shut with no gap |
| Erratic readings | Coil near high-EMI source | Move coil away from VFDs, contactors |
| Phase error | Incorrect orientation | Arrow must point toward load |
| Low accuracy | Conductor not centered | Position conductor in center of coil opening |
RS485 Bus Termination¶
When to Install 120Ω Termination¶
- Required: Bus length > 10 meters
- Required: Baud rate > 9600
- Install: At each physical end of the bus (only 2 resistors total)
- Remove: If present on every node (causes signal attenuation)
Verification¶
Measure resistance across D+ and D- at one end of the bus (power off):
- With termination: ~60Ω (two 120Ω resistors in parallel)
- Without termination: >10kΩ (high impedance)
Getting Support¶
If you cannot resolve an issue, see Support & Contact for support channels.