Modbus IP
Aqua-Scope WiFi devices feature an integrated Modbus TCP/IP server. Modbus IP (also known as Modbus TCP/IP) is a widely used industrial communication protocol that operates over standard Ethernet networks on TCP port 502.
Characteristics:
- Simple, lightweight, and broadly supported
- Data exchange via 16-bit word registers
- No encryption or authentication (use in trusted networks recommended)
Enabling Modbus
Modbus IP is enabled via the app:
- Open the Aqua-Scope App
- Select the device
- Navigate to Configuration → Communication Options
- Enable Modbus IP
The device is then accessible as a Modbus TCP server on port 502 within the local network.
Register Map
Configuration Registers (1–32)
Access: Read / Write
Size: 16 bits per register
Registers 1–32 directly map to the device's internal configuration parameters. Which parameters are available is documented in the respective product manual.
Changing configuration values requires specific knowledge of the respective device's parameters. Incorrect values may impair device behavior.
Sensor Data Registers (from 100)
Access: Read Only
Size: 32 bits per sensor (2 consecutive 16-bit registers)
Each sensor occupies two consecutive registers:
- Even register = upper 16 bits
- Next odd register = lower 16 bits
Register address calculation:
Base register = 100 + (Sensor Index × 2)
| Sensor Index | Register | Description |
|---|---|---|
| 0 | 100–101 | First sensor |
| 1 | 102–103 | Second sensor |
| 2 | 104–105 | Third sensor |
| 4 | 108–109 | Fifth sensor |
Which sensor indices a device supports is documented in the respective product manual.
Valve Control (Register 99)
Access: Write Only
Size: 16 bits
| Value | Action |
|---|---|
0 | Close valve |
| Any other value | Open valve |
Only relevant for devices with valve control (BVS, KFR).
Example: Modbus Access
Using a Modbus TCP client (e.g., mbpoll, pymodbus, Node-RED Modbus node):
# Read temperature (Sensor Index 1, Register 102-103)
mbpoll -a 1 -r 102 -c 2 -t 4 192.168.1.100
# Close valve (Register 99, Value 0)
mbpoll -a 1 -r 99 -t 4 192.168.1.100 0
# Read configuration parameter 1 (Register 1)
mbpoll -a 1 -r 1 -c 1 -t 4 192.168.1.100
Supported Devices
Modbus IP is supported by all WiFi-enabled Aqua-Scope devices: