Minnesota-based RTP Company is a global leader in specialty compounding. The company's specialty thermoplastic compounds provide conductive, structural, wear resistant, flame retardant, soft-touch and color properties in over 60 engineering resins.
To remain on the cutting edge of engineering plastic compounds, RTP needed to expand their business with a new research and development (R&D) center. As part of the R&D center expansion, the plastic extrusion equipment used within the R&D lab needed to be state of the art technology.
RTP's goal was to increase data acquisition capabilities on their plastic extrusion equipment. The engineering effort of new plastic compounds required a high volume of intimate process control information. Plus, the timeline to bring the R&D center on-line was very tight.
The extrusion machine was specified to utilize 15 EZ-ZONE ST integrated control loops from Watlow to control and monitor 15 zones on the extrusion machine. To meet the desire for process and equipment-related data acquisition, the EZ-ZONE ST with digital communications capability was identified to provide system performance data to a programmable logic controller (PLC) (15 registers x 15 zones). The EZ-ZONE ST delivered intelligent data and distributed temperature and power control switching, which unburdened the PLC. Because EZ-ZONE" ST is an integrated control loop, it offers greater ability to monitor system-related information within the thermal control zone.
As a result of using the EZ-ZONE ST integrated control loop, RTP lowered the overall cost of ownership, reduced components required to mount in limited panel space, and saved time by not having to struggle with the time and expertise required with writing PLC temperature tuning algorithms.
Build panels became easier because RTP no longer had to run wires from the back of the machine all the way to the inside front door panels, and less wiring and less termination was required, which improved reliability and saved time and money during installation.
Using all of the following integrated functions resulted in less engineering time and expense to specify the solution:
Limit control for over-temperature protection Mechanical contactor for safety shut-down Solid state relay for heater power switching Heat sink PID temperature control Current measurement diagnostics In addition, EZ-ZONE ST offered TRU-TUNE+, an adaptive PID control algorithm to meet tight temperature control requirements in this dynamic and challenging process application.
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