Mike Dolt Enterprises
Mike Dolt Enterprises
User: zj1090, Location: Portage, Indiana NEC: 2008
Asked on: Tuesday, March 29, 2011 at 11:57 am EDT
Answered on: Tuesday, May 14, 2024 at 3:26 am EDT
Question: We are looking in to installing a PLC chassi with processor and I/O modules outdoors in a NEMA 4x SS enclosure with a heat strip. The temparature in the enclosure during the summer may go up to 120F or may be more (one of the southern state of US). My concern is, eventhough they (Allen Bradely) are industrial rated, we might have intermittent problems. Has anybody done this before.
Can Allen Bradley PLCs Be Installed Outdoors in Extreme Heat?
Yes, Allen Bradley PLCs can be installed outdoors in enclosures with appropriate temperature control measures, but it requires careful consideration and planning.
Temperature Range and Considerations
Allen Bradley PLCs typically have an operating temperature range of 32°F to 140°F (0°C to 60°C). Exceeding these temperatures can lead to intermittent problems, performance degradation, or equipment failure.
Enclosure and Temperature Control
Use an NEMA 4x SS enclosure with a suitable heat strip to maintain the internal temperature within the PLC's operating range. The heat strip should be sized appropriately to prevent overheating or condensation. Consider installing a temperature sensor and alarm system to monitor the internal enclosure temperature.
Other Factors to Consider
Ventilation
Ensure adequate ventilation to prevent heat buildup within the enclosure.
Sunlight
Locate the enclosure in a shaded area or protect it from direct sunlight.
Humidity
High humidity can contribute to condensation and corrosion. Use moisture-resistant components and seal any cable entry points.
Maintenance
Perform regular maintenance and inspections to ensure the enclosure and heat strip are functioning properly.
Recommendations
Consult with Allen Bradley or a qualified industrial electrician for specific guidance on temperature control solutions. Monitor the internal enclosure temperature closely during extreme weather conditions. Consider implementing a redundant system or backup PLC in case of unexpected failures. Train operators on proper maintenance and troubleshooting procedures.
Real-World Examples
Inadvertent outdoor installations of PLCs in southern US states have been successful with proper enclosure and temperature control measures.* However, it's important to emphasize that these installations are not recommended by Allen Bradley and may void warranty agreements.
Conclusion:
While it is feasible to install Allen Bradley PLCs outdoors in extreme heat, it requires careful planning, appropriate enclosure selection, and temperature control measures. Closely monitoring the internal enclosure temperature and implementing redundant systems can help minimize the risk of intermittent problems or equipment failure. Flag for review