Clariant, a producer of plastic additives, is using PROFIBUS to communicate with intelligent HART devices that control the production process. The link between PROFIBUS and HART is a Remote-I/O b lock that translates 4-20mA signals into digital values and transmits the process data over a fast RS485 IS (Intrinsically Safe) PROFIBUS connection through a barrier (RS485 IS to RS485 signal converter) to a DeltaV system (PROFIBUS master).
The system worked efficiently, but it had one major drawback when HART devices were reconfigured. To reconfigure the devices, staffers had to enter the EX area with a notebook, which is certainly not an intrinsically safe device.
Re-configuration came with an immense price tag because it was necessary to formally request a gas clearance certificate. This request begins with informing/alerting the local hospital and the local fire department. Then the production process must be shut down and the hermetic seals around the EX area must be broken. This drawback happened often due to the ever-increasing need to modify the recipe of the plastic additives.
The new solution was elegant and economical at the same time. At the core of the solution is Softing’s PROFIBUS to Ethernet gateway with its capability to run as a non-interfering PROFIBUS master (Class 2 master) parallel to the DeltaV system. In addition, an upgrade of the Remote-I/O blocks was necessary to support the HARTonDP protocol. PactWare™, a free FDT Frame Application, was the solution on the software side. With Softing's PROFIdtm, the HART gateway DTM, and all necessary deviceDTM’s integrated into PACTware, the staff was able to configure the HART device remotely.
"The communication DTM and PROFIBUS/Ethernet gateway from Softing are the central components in our plant. Softing's PROFIdtm provides our FDT based engineering application remote access to field devices via Ethernet. Via the FG PROFIBUS from Softing we can control three Profibus segments in parallel. Softing's components fit perfectly into our architecture and allow us to extend our plant in the future in a very cost efficient way." Ludwig Wenninger, Plant Technics Plastics Additives, Clariant
Today, Clariant’s technicians can access, re-configure, and even diagnose HART devices from their office desktops. The configuration data is routed over Ethernet to Softing’s gateway and then through the barrier to the Remote-I/O blocks. The blocks translate the DP data frames into HART signals that are sent to the field devices. In view of the fact that this solution has significantly cut plant downtimes, it is clear that this investment will pay off very quickly.