The New Metrohm 856 Conductivity Module

The 856 Conductivity Module introduces the new 5-ring conductivity sensors which are far superior to the classical conductivity sensor. The 856 Conductivity Module can be used as an extended measuring input for the Titrando autotitrator or as a standalone instrument with the 840 Touch control.

Whether it is used as an add-on measurement to boost the functions of a Titrando or used as a standalone instrument, the 856 Conductivity Module is a very sophisticated high specification instrument. Historically there was interference to potentiometric measurements when measuring conductivity in the same sample beaker but with the 856 there is a galvanically separated measuring input so conductivity and pH (e.g. with the 867 pH Module or any Titrando) can now be measured in the same beaker.

There are three new conductivity cells to measure from .01 μS – 2000 mS/cm which have the new five-ring technology that allows a wider range of linearity than classical conductivity cells with Pt sheets and shows no wall effect.

Advantages of Metrohm’s new five-ring conductivity cell

Two electrode cell (Generally suited for low conducting solutions)
• Needs platinization to reduce polarisation effects at higher conductivities
• Limited linearity range without platinum black, several different sensors needed to cover wider conductivity range
• Wall effect caused by stray current: Position in the measuring vessel may have influence on the result

Four electrode cell (Platinization not needed)
• Larger linearity range than two electrode cells
• Wall effect caused by stray current: Position in the measuring vessel may have influence on the result

Five electrode cell (Platinization not needed)
• Larger linearity range than two electrode cells
• No wall effect

General Features

• The 856 Conductivity Module is an extension measuring input for any Titrando installation. It can only be used for measurement, not for titration.
• Four MSB inputs for connection of a stirrer (801, 804 or 803) or dosing units.
• Two USB interfaces for connection of a printer, barcode reader, etc.
• The new five-ring conductivity cells allows a wider range of linearity than classical conductivity cells with Pt sheets and shows no wall effect.
• No interference to potentiometric measurements. Conductivity and pH (e.g. with the 867 pH Module or any Titrando) can now be measured in the same beaker.
• Modes: CAL C, MEAS Cond, Dosing (ADD, PREP, EMPTY)
• Fully FDA compliant standalone conductivity meter when using 840 Touch Control