PROFIBUS introduces new profiles for ident systems and weighing & dosage systems
PROFIBUS International (PI) has released two new PROFIBUS profiles for ident systems and for weighing and dosage systems. In the course of the tracking & tracing efforts of several corporations to improve the logistics and traceability legally required by 2005 in the foodstuff and pharmaceutical industry, the simple integration of such systems in higher-level company networks is gaining ever greater importance.
Identification systems based on transponders and barcodes are becoming increasingly important in production processes. They can no longer be ignored today, from product tracking, the identification of individual objects or the saving of data directly on the product. The market appropriately offers a number of devices from various manufactures that are however not compatible with each other in terms of application. On the one hand, the cause of this is a non-standardized "air interface" in transponder systems and on the other, a non-existent standard for transferring data between the PLC and the identification systems. Additional expenditures in operation and integration into control systems are the result.
The situation is similar for weighing and dosage systems. Since nearly all production processes require weighing systems, there are also many different weighing principles in use making just as many different and complex connections to controls necessary. There are currently no international standards that classify the various weighing types.
Ident systems and weighing & dosage systems place high requirements on fieldbus communication, since they have task-oriented demand on cyclical and (in part comprehensive) acyclic communication. Therefore, by creating the new profiles PI has developed a standard for ensuring interoperability between field device application and control program.
With the definition of both profiles new ground has been broken. The details of the field devices were not described, as was previously customary. Instead, so-called proxy function blocks are defined that contain a standardized programming interface (i.e. defined function block inputs and outputs) and subordinate communication mechanisms between the PLC and the field device. Since the blocks have been specified in accordance with IEC 61131-3, it ensures that blocks can be easily ported to different control systems.
The goal of the new PROFIBUS profiles is to achieve the interoperability of products from different manufacturers based on standard proxy function blocks in the control, as well as of standard communication mechanisms between control and field device, which can result in substantial savings in engineering costs with the application. There is another advantage when tendering through well-defined specifications based on appropriate ident devices and weighing/dosing profiles.
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