• 27.04.2020
  • WTW | Process Segment

Instrumentation for EX area for pH/ORP and Conductivity

Instrumentation for EX area for pH/ORP and Conductivity


Unfortunately, at regular intervals explosions are reported in the media - mostly with tragic consequences. Explosion protection is and will therefore remain an enormously important topic in order to avoid high material damage and, above all, to protect the health and lives of employees. The first goal should always be to avoid an explosive atmosphere. If this is not possible, it is important to avoid ignition sources to nullify explosions. Xylem Analytics Germany offers the appropriate measuring instruments for pH/ORP and conductivity.

pH/ORP measurement in wastewater

The SensoLyt® 650-7 EX for explosive areas up to zone 1 includes a long lifespan, an integrated temperature measurement sensor and the ability to simply change electrodes. The SensoLyt® 650-7 EX is a passive armature without a pre-amplifier for high impedance operation.

Depending on the measuring range and application, the respective electrode can be used. The most typical application is to measure in the inlet of a wastewater treatment plant. In this case we recommend the SensoLyt® SEA EX electrode.

The connection to the EX transmitter StratosProA201xpH-0 (with 1 analog output) or -1 (with 2 analog outputs) is made via open cable ends.

Depending on the available voltage, the transmitter is supplied by the respective version of the isolated amplifier WG 21 A7. Data can be transferred to the PLC or the IQ SENSOR NET depending on your needs.

pH/OPR in the process

For measurements in the process industry, specific process electrodes are available. Select the brand “SI Analytics” on the left to optimize the search results.

Conductivity measurement

The analog conductivity sensors TetraCon® 700 EX are available with different cable lengths and provide the highest linearity by way of a 4 electrode system, a wide measuring range and an integrated temperature sensor. They can be used up to zone 1. The inlet of a wastewater treatment plant is the most common application.

They are connected via open cable ends to the transmitter StratosProA201XCond-0 or -1. As with the pH/ORP, the transmitters are supplied by the isolated amplifiers WG 21 A7.

Mounting accessories

Needed mounting accessories for pH/ORP und conductivity locations can be found here.

 Configuration example

Configuration example for measuring pH/ORP or conductivity