The 3‑9900.394 is a field‑installable Direct Conductivity/Resistivity Module that interfaces Signet 2819 -2823 / 2839-2842 electrodes straight into the 9900 SmartPro ® base unit, providing signal filtering, conditioning, and ±2% reading accuracy with auto temperature compensation.

It enables the 9900 to drive isolated 4 -20 mA / relay actions for RO/DI quality interlocks, regenerate triggers, rinse accept/reject, and effluent conductivity alarms — no extra transmitter needed, just slot it in and configure via the ¼‑DIN display.

Xiamen Zhicheng Automation Technology Co., Ltd. is a professional supplier of industrial automation products and solutions, dedicated to providing reliable, cost-effective, and high-performance products to customers worldwide.

With extensive experience in industrial automation and process control, we specialize in supplying a comprehensive range of automation components for industries such as oil & gas, power generation, petrochemical, water treatment, manufacturing, and industrial infrastructure.

• PLC Interface Modules
• I/O Systems and Interface Solutions
• Signal Isolators and Signal Converters
• Relays and Relay Modules
• Industrial Power Supply Units
• Control Valves and Actuators
• Industrial Pumps
• Process Instrumentation

• Professional industrial automation supplier
• High-quality products with competitive pricing
• Fast response and technical support
• Reliable supply chain and stable product availability
• Customized solutions for industrial applications
• Global export experience and customer-oriented service

We are committed to helping customers improve operational efficiency, system reliability, and process performance through dependable automation products and professional support.

Whether you are an end user, system integrator, engineering contractor, or distributor, Xiamen Zhicheng Automation Technology Co., Ltd. is ready to become your trusted partner in industrial automation.