China TDS EC Temperature Meter Manufacturers & Pricelist

Electrical conductivity measures the ionic current carrying capacity of a solution, whereas TDS measures dissolved inorganic mass (mg/L or ppm). Because an electrical probe cannot weigh physical salt particles, it applies a mathematical conversion factor: TDS (ppm) = EC (µS/cm) × k. The factor k typically varies between 0.50 (for monovalent salt profiles like NaCl) and 0.70 (for multi-ion groundwater profiles, such as the 442 standard). Advanced industrial transmitters allow operators to customize this factor or select dynamic algorithmic non-linear curves.

Water viscosity decreases and ionic kinetic velocity increases as temperature rises. For each 1°C increase in solution temperature, apparent electrical conductivity increases by roughly 2%. Without automatic temperature compensation referencing a precision internal Pt100/Pt1000 sensor, an uncompensated meter measuring liquid at 45°C would report a wildly inaccurate EC value nearly 40% higher than the true chemical concentration at standard 25°C.

Contacting sensors rely on electrodes (platinum, stainless steel, or graphite) in physical contact with the sample liquid. They provide ultra-high sensitivity down to pure water levels (0.01 µS/cm), but are prone to fouling, polarization, and scaling in high-salinity or dirty fluids. Inductive (toroidal) sensors enclose wire coils inside chemically inert fluoropolymer (PVDF/PEEK) housings. They induce a current in the liquid through magnetic coupling, making them immune to electrode fouling and ideal for harsh chemical baths, brine concentration, and sewage.

BOQU industrial online meters provide multiple simultaneous output options: isolated 4-20mA current loops with programmable ranges, dual SPDT mechanical relays for high/low alarm triggers and pump dosing, and RS485 Modbus RTU serial communications. Smart digital IoT sensors transmit Modbus directly from the probe cable, allowing direct multi-drop connection to PLCs, gateways, or SCADA panels without external transmitters.

All BOQU instruments and sensors are fabricated in Shanghai under audited ISO 9001 quality management and ISO 14001 environmental safety frameworks. Products carry European CE conformity, SGS factory audit verification, and FDA material compatibility declarations for sanitary contact surfaces. Products include a standard 12-month factory replacement warranty and lifetime calibration firmware support.