• Process connection: 3/4 inch MNPT
  • Temperature: 32 to 221°F (0 to 105°C)
  • Temperature (option -60): 32 to 392°F (0 to 200°C)
  • Pressure: 250 psig (1825 kPa abs) maximum
  • Vacuum: 7.4 psia (51 kPa abs)
  • Cable length options:
    • 10ft cable standard
    • 50ft cable optional
  • Wetted materials:
    • Electrodes; titanium
    • Body; 316 stainless steel
    • Insulator; PEEK
    • O-rings; Viton


The Rosemount Analytical Model 400 /400VP Endurance Conductivity Sensor are designed for direct screw-in insertion into process piping using a 3/4-inch MNPT fitting. The Model 400 sensors can also be used in sidestream samples. A 1-inch pipe tee with a 3/4-inch bushing is a suitable flow cell. A 3/4-inch pipe tee can be used with 0.1 and 1.0/cm cells. A transparent plastic flow cell is also available (PN 24091-02).

ENDURANCE sensors are contacting conductivity sensors. They are available in cell constants of 0.01, 0.1, 1.0, and 10/cm. The choice of cell constant depends on conductivity. High conductivity samples require larger cell constants. Consult the analyzer Product Data Sheet for recommended ranges and accuracy.

Sensors with 0.01, 0.1 and 1.0/cm cell constants have concentric titanium electrodes separated by a PEEK insulator. Viton O-rings seal the internal parts of the sensor from the process liquid. Sensors with 10/cm cell constants have graphite electrodes and an epoxy body.

Electrolytic conductivity is a strong function of temperature, and conductivity readings are typically converted to the value at a reference temperature. To measure temperature, ENDURANCE sensors use a platinum RTD. In metal electrode sensors the RTD is inside the inner electrode. In the epoxy body sensor, the RTD is in a titanium thermowell protruding from the end of the sensor.

The Model 400 sensor is available with Variopol 6 quick disconnect watertight connectors. Wire the interconnecting cable to the analyzer and run the cable to the sensor. The sensor plugs into the cable receptacle. To replace the sensor, simply disconnect the Variopol fitting and plug in a new sensor. There is no need to rewire or rerun cable.


This product can be used in the following applications:

Here's how some of our customers use this product...

TDS in Rinse Loop

The Background: Our customer operates a chemical plating and etching facility. To control their production costs, they create their own demineralized rinse water via reverse osmosis. The customer seeks a way to measure the amount of total dissolved solids (TDS) in this rinse water to ensure it meets their standards for rinse water as well as to determine the overall health of their reverse osmosis system.

The Problem: TDS isn't a directly measurable parameter. Instead, electrical conductivity is measured and a correction factor is applied to the conductivity reading to obtain the TDS value. The correction factor varies and accounts for the minerals and salts that give the water its qualities.

The Solution: We recommended the Rosemount Analytical 400 series conductivity probe paired with the Rosemount Analytical Model 1056 analyzer. This combination creates a simple and effective system to prevent unclean water from entering the process. If the 1056 detects a TDS value above the customer defined threshold of 200ppm, the relay closes a vale and prevents the out-of-tolerance water from ever reaching the critical processes elsewhere in the facility.

In Stock

Part Number Price Available
$701.00 2 in stock
$701.00 2 in stock
$715.00 2 in stock

Interested in Other Part Numbers?

Other part numbers are available to order but are not currently in stock. Current availability for non-stock parts is "Usually ships in 2 weeks". Click here to select options