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Header image Energie-to-Components
The Carlo Gavazzi Group

Solid state relays ready for IIoT

Thermoforming equipment typically utilizes a series of single phase heating elements to heat the plastic sheet to the forming temperature. In recent years, there has been a growing trend towards sustainability and reducing carbon emissions including in the plastics and rubber industry.
The NRG digital solid state relay solution integrates current, voltage, energy and other electrical variables within the solid state relay. This real-time monitoring data is then exchanged with the NRG controller which, in turn, exchanges data with the machine's PLC. Apart from saving considerable wiring time, NRG enables OEMs to improve their process control and, with the integrated diagnostic functions, may also predict heater failure thereby reducing machine downtime.

Partial heater break detection

Heater breakdown and thermal runaway due to a shorted heater, are two critical issues in most plastic processes.
A failure of the heater will cause a drop in temperature in the heating zone, thereby increasing friction on the screw, resulting in overheating and barrel wear.
If a heater shorts out, the temperature in that specific area cannot be controlled and can cause the plastic to overheat resulting in significant material scrap.
The RGC1S solid state relay and contactor series integrates current monitoring to detect total and partial heater failures.
Based on a "teach" function, the RGC1S compares the measured current to the one stored during the "teach" function and checks for current deviations for up to 6 heaters connected to the relay. The status of the relay is available via a transistor output with normally open (NO) or normally closed (NC) logic.

Real-time heater monitoring

Monitoring the status of the heating elements is crucial to ensure a uniform heating across the plastic sheet. Whereas NRG provides an all-in-one solution that also includes fieldbus communication, sometimes OEMs just want to know the status of the SSR and heater. In these cases, the RGS...M and RGC...M series of solid state relays and solid state contactors, provide the optimal solution. In addition to the standard switching function, the RG monitoring variants include internal diagnostics such as mains loss, load loss and SSR short. Status of the relay is then communicated to the machine's PLC via a transistor output with normally open (NO) or normally closed (NC) logic.

Maintaining stable temperature control

Fast switching of heaters results in a more precise temperature control. Solid state contactors like the RGC and RGS solid state relays, can switch on and off within half a mains cycle respectively. This rapid turning on and off allows the heater to be switched multiples times every second to avoid temperature overshoots.
The RGC and RGS series have been tested to 100 kA short circuit current rating according to UL508 for an easier integration into industrial panels. The high I2t (up to 18,000 A2s) within the RGC series also allows protection with miniature circuit breakers (MCBs) for a lower installation cost.