Safety at Work Installation Certification Applications

AS-Interface in THE chemical Industry

Production monitoring in EX Zone 0, acetone vapor

Cellulose is a versatile material, the best-known and most common material as foundation for paper production. However, cellulose fibers are also suitable for other products, for example, as a raw material for filters. To be used as a filter, the cellulose requires a pretreatment that also involves the use of the highly explosive acetone. Continuous production diagnostics in this environment is difficult, but possible with so-called Namur sensors. This plant in the Brazilian state of Sao Paulo  uses about 1000 of these sensors (EXi).

Naturally, such an installation in Ex zones can be wired in the common way with appropriate sub-distributors and complex installation technology. However, there is a much better option that not only significantly reduces the installation effort and costs, but also offers additional diagnostic possibilities.

This project used 300 special AS-Interface modules from Sense. On site, the entire production line consists of 14 machines, each equipped with an AS-Interface network.

AS-Interface offers the simple wiring and connects sensors and actuators with the control system. For this purpose, the AS-Interface transmits power and data on a two conductor cable to the connected devices.

AS-Interface is used for wiring in zones 1 and 2. AS-Interface technology supplies the power for all connected devices through a single cable, offering advantages in wiring and omitting additional lines while bringing additional potential ignition energy into the hazardous areas.

For this reason, the system is only used for zone 1, from where the Namur sensors are then routed into hazardous zone 0.

This installation was made possible by the ASI3.2-MD-4EN-Ex modules from SENSE, which have the appropriate approvals for use in such environments. Further information about the module at: