How to Connect a Conductivity Analyzer Over RS485 Modbus RTU: AEC1-T1 T2 Integration

Connecting a conductivity analyzer to a PLC or SCADA system is a common integration task. This guide explains how the Daruifuno AEC1-T1 T2 online conductivity controller uses RS485 Modbus RTU and what you need to know to get it online quickly.

Step 1: Confirm the Interface

The AEC1-T1 T2 provides an RS485 port supporting the standard Modbus RTU protocol. Wire the D+(A) and D−(B) terminals to your bus and daisy-chain additional slaves as required.

Step 2: Set the Communication Parameters

The default settings are 9600-8-N-1 with slave address 1. If your network uses different values, change them from the communication settings menu on the instrument.

Step 3: Read the Measurement Registers

The controller acts as a Modbus slave. Use function code 04 to read the values, each stored as 32-bit floating point (CDAB):

Step 4: Add Analog or Relay Control if Needed

In addition to the digital link, the controller offers two active 4–20mA outputs (max. load 1000 Ω) and two SPST relays rated 3A 250V AC, allowing it to drive dosing pumps, valves and alarms directly.

Frequently Asked Questions

Which protocol does the analyzer use?
Standard Modbus RTU over RS485.

Is the register map documented?
Yes, temperature, conductivity, resistivity, TDS and salinity registers are fully defined.

Can I also use analog output?
Yes — two 4–20mA outputs mirror the measured values for recorders and legacy loops.

Typical Integration Scenarios

Across the water industry, the AEC1-T1 T2 supports a wide range of integration projects, including:

• Wastewater plants logging conductivity trends to a central SCADA server
• Pure water skids reporting resistivity directly to a PLC for valve control
• Cooling water loops raising alarms through the relay contacts
• Cloud-connected systems polling Modbus registers for live dashboards

Commissioning Tip

Take a note of the default 9600-8-N-1 setting and slave address 1 before you begin. If your network differs, adjust both from the communication settings menu so the controller responds correctly on the first poll.

About Daruifuno

Suzhou Delfino Environmental Technology Co., Ltd. designs and manufactures water analysis instruments and sensors, supplying online, portable and laboratory products to customers around the world since 2015.

Contact Daruifuno for the complete Modbus register map, integration guidance or a sample unit for evaluation.