Agrowtek SXH Hydroponics Sensor
Water sensor transmitter for nutrient solution temperature, pH, EC and ORP or dissolved oxygen.
The Agrowtek SXH is a hydroponics sensor transmitter that measures temperature, pH, electrical conductivity and, on the SXH+, ORP or dissolved oxygen of the nutrient solution in greenhouse and indoor fertigation. This Modbus RTU template reads all water values and identification through the LX2 ModLINK, and lets you run zero and span calibration and change units from ModbusCloud.
- Protocol
- Modbus RTU
- Connection
- RS485, 19200 baud
- Registers
- 28, read and write
- Brand
- Agrowtek
- Key readings
- Solution temperature · pH · Electrical conductivity · ORP or dissolved oxygen
- Available commands
- Zero calibration · Span calibration · Analog output calibration · Measurement units
- Compatible models
- SXH · SXH+
- Last updated
Registers (28)
14 read, 15 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Temperature | °C | Read | |||
| pH | pH | Read | |||
| Conductivity | µS/cm | Read | |||
| ORP / DO / Flow | Read | ||||
| Temperature Float | °C | Read | |||
| pH Float | pH | Read | |||
| Conductivity Float | µS/cm | Read | |||
| ORP / DO / Flow Float | Read | ||||
| Toggle Units | Write | ||||
| Temperature Zero Calibration | °C | Write | |||
| pH Zero Calibration | pH | Write | |||
| Conductivity Zero Calibration | µS/cm | Write | |||
| ORP / DO / Flow Zero Calibration | Write | ||||
| Temperature Span Calibration | °C | Write | |||
| pH Span Calibration | pH | Write | |||
| Conductivity Span Calibration | µS/cm | Write | |||
| ORP / DO / Flow Span Calibration | Write | ||||
| Temperature Analog Output Calibration | Write | ||||
| pH Analog Output Calibration | Write | ||||
| Conductivity Analog Output Calibration | Write | ||||
| ORP / DO / Flow Analog Output Calibration | Write | ||||
| Clear Calibration | Write | ||||
| Device Address | Read and write | ||||
| Serial Number | Read | ||||
| Date of Manufacture | Read | ||||
| Hardware Version | Read | ||||
| Firmware Version | Read | ||||
| Device Model | Read |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Show pH, EC and solution temperature of each nutrient tank on one ModbusCloud dashboard.
- Get an email or webhook when pH or EC leaves the band you set, with one rule for each limit.
- Compare EC of supply water and drain water from two sensors over 365 days of history.
- Catch a fouled pH probe with the automatic monitoring, which reports a value that stays exactly the same for hours.
- Run pH 7 and pH 4.01 calibration from the portal by writing the buffer values to the zero and span registers.
Installation
Mount the SXH near the tank or line and fit the pH, EC and temperature probes and, on the SXH+, the ORP or DO probe. Keep pH and ORP tips wet.
Connect the GrowNET port to an Agrowtek LX2 ModLINK, directly or through an HX8 hub, and wire TX/RX+ and TX/RX- of the LX2 to the RS485 terminals of the ModbusCloud Gateway. Terminate the bus.
Give the transmitter its own address from 1 to 247 in its setup menu or with the AgrowLINK utility.
In ModbusCloud, add a Modbus device with protocol RTU, the address, 19200 baud, 8 data bits, no parity and 1 stop bit, and import this template.
Check pH and EC against a buffer or reference solution before you rely on alarms.
Things to watch for
The SXH does not answer through the LX2. What should I check?
Check 19200 baud, no parity, 1 stop bit and the transmitter address in ModbusCloud; the LX2 may have been set to another speed with the ModLINK utility. Swap TX/RX+ and TX/RX- if nothing comes back, terminate the RS485 bus, and give every GrowNET device behind the LX2 its own address.
EC reads about half of what I expect. Why?
The conductivity channel is probably set to ppm instead of microsiemens; on the SXH scale 2500 ppm matches 5000 µS. Change the EC units in the transmitter menu or write 3, the channel number of conductivity, to Toggle Units.
What does the fourth value mean on my SXH?
It carries ORP in mV on an SXH+ with an ORP probe, or dissolved oxygen with a DO probe. The scaled value is mV as is, or mg/L times 100 for DO. The floating-point value shows the reading directly, so use that one if you are not sure which probe is fitted.
How do I calibrate pH from ModbusCloud?
With the probe in pH 7 buffer, write 7.00 to pH Zero Calibration; then in pH 4.01 buffer write 4.01 to pH Span Calibration. Always zero before span. For EC write 1413 to the span register in a 1413 µS standard. Writing is off per gateway by default; request it for the gateway in the portal.
Can I plug the GrowNET cable into the network port of the Gateway?
No. GrowNET uses RJ45 plugs but it is not Ethernet. Connect the SXH to the LX2 ModLINK and wire the LX2 to the RS485 terminals of the ModbusCloud Gateway.
Want to see how it works?
