How Connectivity Works for Level Sensors
HPzenAi LS-PRE level sensors do not connect directly to Wi-Fi. Each sensor communicates with the HPzenAi Gateway over RS485 Modbus RTU — a wired industrial protocol that is reliable, noise-immune, and capable of running up to 100 m without repeaters. The gateway then forwards all sensor readings to the HPzenAi cloud over its Wi-Fi or SIM connection. This means the gateway must be online before sensor data can reach the app.
Before You Start
Complete these steps before attempting to link the level sensor.
- 1HPzenAi Gateway powered on and connected to the internet — confirm the LED is solid green.
- 2Gateway registered in the HPzenAi app and showing Online status.
- 3Level sensor physically installed in the tank with the sensor body submerged.
- 4RS485 cable wired from the sensor to the gateway terminal block.
- 512V DC power applied to the sensor.
Step 1 — Complete Gateway Wi-Fi Setup
The gateway must be online before you can link any field device. If the gateway has not yet been configured, complete the Wi-Fi setup first.
- 1Set up the gateway Wi-Fi using the guide at IoT Gateway → Wi-Fi Setup Guide.
- 2Confirm the gateway LED is solid green and the gateway shows Online in the app.
- 3If using SIM connectivity (GW-1, GW-2), confirm the SIM LED is solid amber if Wi-Fi is unavailable.
Step 2 — Wire the Sensor and Apply Power
With the gateway online, connect the sensor RS485 cable to the gateway terminal block and apply 12V DC power to the sensor. The gateway begins scanning the RS485 bus automatically within 60 seconds.
Image
- 1Connect RS485 A wire to the RS485 A terminal on the gateway.
- 2Connect RS485 B wire to the RS485 B terminal on the gateway.
- 3Connect the sensor 12V DC power wire to the gateway 12V output or a dedicated 12V supply.
- 4Tighten all terminal screws firmly.
- 5Wait 60 seconds for the gateway to detect the sensor on the bus.
Step 3 — Link the Sensor in the App
Once the gateway detects the sensor on the RS485 bus, it appears as a Discovered Device in the app. Complete the linking process to name the sensor and begin monitoring.
Guided Help Center
Open the HPzenAi app.
Step 4 — Verify Live Readings
After linking, confirm the sensor is delivering accurate live data before configuring alerts.
- 1Open the sensor device tile in the app — live level readings in mm, metres, and percentage should be displayed.
- 2Compare the displayed level against a physical measurement or known tank level to verify accuracy.
- 3If the reading is zero or unexpected, refer to the Troubleshooting guide.
- 4Confirm readings update periodically — the default polling interval is 1 minute.
Gateway Wi-Fi Signal Requirements
The gateway requires adequate Wi-Fi signal strength for reliable cloud synchronisation. If the gateway location has a weak signal, use a Wi-Fi repeater or upgrade to a GW-1/GW-2 with SIM fallback.
- 1Minimum recommended Wi-Fi signal at the gateway: −75 dBm.
- 2Check signal strength in the app under Gateway → Settings → Network → Wi-Fi Signal.
- 3Sensor readings are buffered locally on the gateway for up to 24 hours if cloud connectivity is lost — data is uploaded automatically when the connection is restored.
- 4For remote agricultural or off-grid sites, use GW-1 or GW-2 with a SIM card for permanent cellular backup.