Trace heaters are used for the electrical temperature control of media during conveying between plant components. In the specific application, raw material is conveyed into extruders over longer distances. Particular emphasis is placed on the maintenance of a pipe temperature level of 75 ° C. Therefore heat conductors are attached along the pipeline in order to heat them by means of current if necessary.
Trace heating system
Former cabinet configuration
So far, the structure of the system consists of two spatially separate cabinets each with 18 consisted single controllers that gated for the trace heating. As part of a comprehensive modernization and expansion control technology for heating should be completely renovated. Offering a comfortable touch operation for all control loops the requirement that the scheme is coupled via a SIEMENS S7 with other system components existed. In addition, all control circuits should be designed with redundancy so that a second regulator acts as a limiter and engaging in case of temperature deviations.
The solution was the multichannel temperature controller FP1600. Due to its modular design, all 36 individual controllers could be replaced by one processor unit. The processor is then individually expanded by input and output modules. The local distance between the two control cabinets can be simply bridged over a bus line between the FP1600 components.
Cabinets including FP1600 and touch IPC
Due to the fully modular design of the FP1600, input and output modules can be specially configured according to customer requirements. For the temperature detection of the actual value, Pt100 3-wire modules were used in the specific application, which guarantee a high measuring accuracy. The output modules were implemented as 24V digital outputs. Switching relays, which are controlled by the FP1600 output module, are used to switch the heating current required by the trace heating system.
The process visualization Visual Fecon is used to visualize all plant components. Each cabinet was equipped with a 15 “touch IPC, which functions as a parameterization and monitoring unit and provides the plant operator with a quick overview of the process values.
In connection with the trend towards industry 4.0 and the associated networking of plant components, the FP1600 was connected via a real-time Ethernet interface and ProfiNet to a PLC. In addition to the centralized recording of data, the coupling also offers the advantage of remote monitoring and maintenance.