Installation of PLC Control Panel Complete Guide for Safe & Reliable Operation

PLC control panel installation guide covering temperature, humidity, vibration, and safety for reliable automation.

Introduction

• In order to ensure the reliability and security of the system, prior to the design of the system it is important to make certain that the conditions in which it will be installed is well understood.
• Basically, the stresses on the PLC system (temperature, humidity, vibrations, shocks, corrosive gases, over-current, noise etc.) need to be reduced as much as possible.
• By taking advanced measures to prevent problems, the reliability of the system can be improved, and in the long-term the operation rate can also be increased.

Installation of PLC Control Panel

Installation & Environmental Conditions for PLC Control Panel

The following describes the environmental conditions and measures to be taken for the installation of the PLC control panel.

Temperature

• Based on the operating temperature of the element parts of the PLC, the operating temperature for the system is generally between 5°C and 40°C.
• At the same time, with both forced and natural cooling of the panel, the fact that it is miniaturized to save space means that from our experience the temperature of the panel is sometimes 10°C to 15°C higher than the ambient temperature of the room.
• As such, it is important that the following measures be taken depending on the installation site and the temperatures being generated to make certain that the panel's internal temperature does not exceed the range of the unit operating temperature, and to provide a sufficient margin for the range of operating temperature.

High Temperature

1. Natural Cooling (Natural draft at the top and bottom of Panel) When installing the panel, it is optimal not to make use of cooling devices such as fans and coolers.

The following are important points in the installation of the PLC.

Natural Cooling System

• Do not install in the upper part where the warm air in the panel stagnates
• In order to ensure ventilation space, maintain a sufficient distance from other machinery, wiring ducts etc around the panel.
• Do not install in positions other than those specified (for example upside down), which can lead to the generation of abnormal heat within the PLC
• Do not install directly above devices that generate heat such as
• heaters, transformers and high-capacity resistors etc.
• Avoid direct sunlight

2. Forced Ventilation (forced ventilation by use of a fan directly mounted at Top of Panel).

Controlled Ventilation System

3. Controlled Circulation (controlled circulation by means of a fan in the airtight enclosure panel).

Controlled Circulation System

4. Full Room Cooling (Use a cooler to cool the entire room in which the panel is installed).

Room Cooling System

Notes:

Environmental conditions and cooling system should be as follows.

• Panel installed in room with low dust - 1 or 2
• Panel installed in room with dust - 3 or 4

When using a fan

• Attach an air filter to the suction mouth to prevent the entry of dust.
• Periodically wash the air filter in water.
• Temperature sensors should be attached near the PLC to emit an alarm in the event that the fan or air conditioner break down etc.

Low-Temperature Conditions

• In cold areas where the morning temperature falls below 0°C at the time of start-up, attach a small space heater inside the panel to heat the internal temperature to about 5°C. 
• In order for the PLC power supply to generate heat, don't turn off the power.

Humidity Control

• In order to maintain the insulating properties of the PLC, relative humidity should be kept within the range of 35% to 85%. 
• In particular in the winter, when heaters are turned on and off, sudden changes in temperature may be experienced resulting in condensation which can lead to shorts or malfunctions. 
• Where there is danger of such a change in temperature, power should be kept on during the night and condensation should be prevented through such measures as installing a small heater inside the panel to maintain low heat.

Humidity Control

Vibrations & Shock Protection

• The PLC is tested in accordance with the environmental (electricity and electrons) the sine wave vibration test method and the shock test method, so that vibrations and shocks in the general specifications will not cause malfunctions.
• However, the system should not be installed in a place where it will be subject to regular vibrations or shocks, especially to the PLC and the panel.
• The following methods may be used to reduce the effect of vibrations and shocks.

Vibrations & Shock Protection

• For vibrations and shocks that originate externally, the panel should be removed from the source. Alternatively, the PLC and the panel should be protected with the use of rubber.
• Isolate vibrations such as through the construction of the building, flooring etc.
• Regarding shocks experienced during magnetic contactor operation in the panel, the source of the shock or the PLC should be protected by rubber so that the shock is not felt.

Atmospheric Conditions

When using the system in any of the following kind of places, connections may be loosened or elements and parts may experience corrosion, and an air purge should be implemented to avoid this.

Atmospheric Conditions

• Places where dust, salt particles, soot or organic solvents etc are common, and where the enclosure is sealed in such a way that the internal temperature does not increase very much.
• Where corrosive gases are common, an air purge (air purification) of the panel should be performed, to pressurize the panel and prevent the intrusion of air from outside.
• Places with flammable gases may be a cause of ignition. The system should not be used without a fire prevention mechanism in place.

Workspace & Maintenance Requirements

• Make sure that there is sufficient space to operate programs and to replace the unit. Further, for the sake of safety and maintenance, installation should be as far as possible from high pressure or high power devices.
• Mount the PLC and I/O unit in a position in which the use of the debugging tool and the connection and operation of peripheral devices will be possible.
• The PLC and I/O unit generally has a maintenance light, and this should be easy for the operator to see, and in a position where it can easily be reached.

Workspace & Maintenance Requirements

• For systems using the PLC as a control system, it is likely that there will be future additions and alterations to the system, so approx. 10-20% extra space should be allowed for this.
• Where necessary, about 600 mm of space should be kept behind the panel for the purpose of performing maintenance.

Practical example:

• In the PLC and HVAC controller manufacturing industry, companies such as Siemens, Honeywell, Trend Controls, Danfoss, Omron, Schneider Electric, Johnson Controls, and Delta Controls clearly specify ambient conditions and protection classifications within their technical datasheets.
• These specifications define the environmental limits under which the equipment can be transported, stored, and operated safely and reliably.
• For practical understanding, let us consider the Siemens Climatix series HVAC controller datasheet as an example. The referenced table column outlines the device’s ambient environmental conditions and protection classification requirements.
• In this article, we will focus specifically on the ambient environmental conditions. The protection classification (such as IP rating and enclosure protection) will be discussed separately in a dedicated blog post.

Siemens Climatix series HVAC controller

Transport (in transport packaging) as per EN 60721-3-2: Class 2K12

• EN 60721-3-2 is a European standard that classifies environmental conditions during transportation of equipment.
• It defines the climatic and mechanical stresses a device can withstand while being transported, not during operation. 
• The Class 2K12 defines a specific climatic stress level during transport.

Temperature: -25...70 °C,

• The device (inside its transport packaging) can safely withstand minimum -25°C to maximum +70°C.

Air humidity: 5…90 % (non-condensing),

• Relative humidity can vary from 5% to 90%, Moisture must not form water droplets on the device.
• Note: Condensation could damage electronics, so this condition prevents moisture-related failures.

Operation as per EN 60721-3-4: Class 4K23

• EN 60721-3-4 defines environmental conditions for stationary use at non-weather-protected locations.
• Class 4K23 means the equipment is designed for harsh outdoor climatic environments.

Temperature: -40…70 °C

• Operate normally at -40°C (very cold climate)
• Operate up to +70°C (high ambient temperature)
• NOTE: Avoid exposure to maximum temperatures for prolonged periods.

Air humidity: 5…90 % (non-condensing)

• Relative humidity can vary from 5% to 90%, Moisture must not form water droplets on the device.

Air pressure: Minimal 70 kPa

• Standard atmospheric pressure at sea level: 101.3 kPa.
• Minimum allowed pressure: 70 kPa. 
• (corresponds to a maximum 3000 m above sea level)
• So, the device can operate safely up to high-altitude installations.

Mechanical ambient conditions

• EN 60721-3-2 defines environmental conditions during transportation.
• Class 2M4 indicates relatively severe mechanical stress during transport.

What Type of Mechanical Stresses? 

• Under Class 2M4, the device (inside its packaging) may be exposed to:
• Vibration: (From trucks, Rail transport, Air cargo, Sea freight0
• Shock: (Handling impacts, Loading/unloading Accidental drops (within specified limits))
• Rough handling conditions: The equipment must not suffer mechanical damage when properly packed.

Operation per EN 60721-3-3: 

Class 3M11, continuous operation,

Class 3M12, vibration peaks. what it mean?

• The device complies with mechanical environmental conditions for stationary use in accordance with EN 60721-3-3, Class 3M11 for continuous vibration exposure and Class 3M12 for intermittent vibration peaks.
• 3M11:  Safe for continuous industrial vibration,
• 3M12: Safe for occasional higher vibration spikes,

Conclusion

A professionally installed PLC control panel ensures long-term reliability, equipment protection, and safe operation. By controlling environmental factors such as temperature, humidity, vibrations, and atmospheric conditions, the lifespan of the PLC system increases significantly.

Following these installation guidelines helps engineers, technicians, and automation professionals achieve optimal system performance worldwide.

About the Author – Insight Control System

Insight Control System provides technical education and practical guidance in the fields of Building Automation Systems (BAS), HVAC controls, PLC programming, sensors, and industrial automation. The content published on this platform is based on field experience, technical documentation analysis, and real-world system applications.

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