Clams are extremely sensitive to water quality. Even short-term deviations in dissolved oxygen, pH, temperature, or salinity can cause clams to close their shells, stop feeding, or even die in large numbers. Traditional experience-based, occasional spot-checking methods cannot cope with sudden water quality deterioration. To increase production and income, a 24/7 automated monitoring system that intervenes immediately when thresholds are exceeded is essential. The BLIIOT BL192Pro IoT-based water quality monitoring IO module can provide valuable support for such data monitoring.
|
Water Quality Parameter |
Optimal Range |
Consequence of Exceeding Limits |
Sensor Type |
Output Signal |
|
Dissolved Oxygen (DO) |
≥5 mg/L |
Oxygen deficiency causes shell closure, breathing obstruction |
Optical/electrochemical DO sensor |
4-20mA or RS485 |
|
Water Temperature |
25-30°C |
Above 35°C → shell closure; 40°C → death |
PT100/PT1000 RTD |
RTD or 4-20mA |
|
pH Value |
7.8-8.3 |
>9 or <7 leads to prolonged shell closure |
pH electrode |
RS485 or 4-20mA |
|
Salinity |
20-35 ppt (depends on species) |
Sudden salinity change causes osmotic stress |
Conductivity/salinity sensor |
RS485 |
|
ORP |
Local baseline |
Too low indicates anaerobic decomposition of bottom sediment |
ORP electrode |
RS485 or 4-20mA |
|
Ammonia Nitrogen (NH₃-N) |
As low as possible |
High concentration is toxic to clams |
Ammonia sensor |
RS485 |
Most industrial water quality sensors provide either a standard RS485 (Modbus RTU) interface or a 4-20mA analog output – exactly the types of signals the BL192Pro can directly acquire.
Use Y31 (4-20mA), Y33 (0-5V/0-10V) or Y36 (±5V/±10V) AI modules – 16-bit resolution, automatically converts current/voltage to engineering values (mg/L, °C, pH, etc.).
Use Y51/Y52 (PT100/PT1000 RTD) or Y58 (thermocouple) modules – 3-wire or 4-wire connection, outputs temperature directly.
One isolated RS485 port (expandable to 5 ports with Y61 module), supports 2400–230400 baud, Modbus RTU master mode. Up to 25 Modbus commands can be created to automatically poll sensors and store data into mapping addresses (10000–49999).
Use Y11 (NPN) or Y12 (PNP) DI modules – supports dry/wet contacts, collects pump running status, high/low level alarms, etc. Mapped to addresses 2000–2999.
Use Y21 (PNP DO), Y22 (NPN DO) or Y24 (2A relay output) modules – controls aerators, water pumps, feeders, valves, etc. Mapped to addresses 1000–1999.
Two 10/100M adaptive Ethernet ports with built-in switch functionality. BL192Pro supports three protocols:
BL192Pro has built-in arithmetic, logic, and conditional operation modules – no programming required to configure automation rules. Three practical examples:
In the Logic Operation page, add a rule: Input 1 selects the DO sensor register (e.g., REG3000), operator <, threshold 5.0, Output Address selects the DO register that controls the aerator (e.g., REG1001). When DO < 5 mg/L, the DO closes to start the aerator; when DO recovers, it automatically turns off.
Configure a rule: Input 1 selects the temperature register (e.g., REG3002), operator >, threshold 32°C, Output Address selects the relay for the circulating pump (e.g., REG1002). When water temperature > 32°C, the pump automatically starts to bring in cooler water; it stops automatically after cooling down.
Use the combinational logic function: first create Logic1 to determine if pH < 7.8 OR > 8.3, and Logic2 to determine if ORP is below threshold. Then connect them with an AND relationship and output to an alarm DO register. The audible/visual alarm is triggered only when both conditions are met simultaneously, avoiding false alarms from a single sensor.
The system consists of four layers:
From "farming by experience" to "farming with knowledge", the BLIIOT BL192Pro IoT-based water quality monitoring IO module enables clam farmers to achieve automated water quality monitoring and control through a simple web configuration. Real-time monitoring of key parameters such as dissolved oxygen, pH, temperature, and salinity – with automatic start/stop of aerators and circulating pumps when thresholds are exceeded – ensures that clams are always in an optimal growing environment. This shortens the growth cycle, improves size uniformity at harvest, and ultimately increases production and income.
