Toroidal conductivity probe C8825.4 | RS485 Modbus RTU and 4-20 mA

The toroidal conductivity probe C8825.4 The B&C Electronics product is designed for continuous measurement of electrical conductivity and TDS in industrial processes, especially in applications where conventional electrode sensors can be affected by fouling, dirt, polarization, or solid buildup.

Its toroidal inductive measuring principle allows measurement without metal electrodes in direct contact with the fluid, offering a robust solution for industrial waters, brines, seawater, chemical processes, CIP circuits, WWTPs, ETAPs and applications with liquids of high conductivity or high solids load.

The C8825.4 has analog output 4-20 mA and digital communication RS485, allowing its integration into PLCs, SCADA systems, data loggers, acquisition cards, and industrial controllers. In digital mode, the probe simultaneously transmits conductivity, TDS, and temperature values.

Measurement ranges and TDS

The probe allows you to select different conductivity scales, from 0…4,000 ms until 0…2000 mS, as well as TDS scales from 0…2,000 ppt until 0…1000 ppt. The TDS/EC conversion factor is configurable, allowing the measurement to be adapted to the characteristics of the fluid or the process.

RS485 Modbus RTU Communication

The C8825.4 incorporates communication RS485 Modbus RTU and the proprietary B&C ASCII protocol. The Modbus protocol allows reading measurements, modifying parameters, and performing calibration operations using the functions 03, 06 and 16. The Modbus address is configurable from 1 to 243 and the communication speed can be set to 2400, 4800, 9600 or 19200 baud.

Temperature calibration and compensation

The probe incorporates a Pt100 temperature sensor for automatic conductivity compensation. The reference temperature can be set to 20 °C or 25 °C, and the temperature coefficient is adjustable between 0.00 and 3.50 %/°C.

Calibration can be performed via digital communication, including zero calibration, sensitivity calibration with a standard solution, and factory reset. The temperature coefficient of a KCl standard solution can be used during sensitivity calibration.

RT90 digital filter

The device incorporates a digital filter with two configurable RT90 response times, one for small and one for large signal variations. This allows for stable readings under normal process conditions while maintaining a fast response to significant changes in conductivity.

Industrial facility

The C8825.4 model features a PVCC body, protection grade IP68, 10-meter cable and process connection via male thread 1½" NPT. It can be installed by immersion or in a pipe, always maintaining an adequate separation from metal walls or conductive surfaces to avoid measurement errors.

For immersion installations, the SZ7531 adapter and suitable extension tubes can be used to protect the cable and facilitate assembly in tanks, channels or open conduits.

Download the user manual for the C8825.4 toroidal conductivity probe.