What Does SCADA Stand For?
Supervisory Control and Data Acquisition Systems refer to remotely located systems that automatically collect data on electrical equipment for monitoring and control. The arrangements are designed to reduce the cost of having a person physically reading instruments and changing settings of operating controls in these remote areas.
It also allows for this monitoring/supervising multiple systems in one central location. These systems existed long before the computerization of cloud-based networks and SOC, security operation centers, for SCADA networks.
Why is Weather an Issue in SCADA Design?
The electronic equipment and computer systems required for monitoring and controlling the remote devices must be able to operate in extreme conditions of both heat and cold. These same extreme conditions and changes cause changes inside the electrical enclosures which typically are not vented to the outside environment.
Being isolated from outside air and moisture does not prevent internal air temperatures from changing or moisture from forming.
What Type of Applications Use SCADA?
Long before the internet of things and cloud computing or even cell phones SCADA systems controlled industrial control and monitoring systems in remote areas. Hard wiring or microwave signals were used to send and receive data from remote locations.
Early applications for remote sensing, data acquisition and control systems were
Todays’ systems are going farther than anyone ever imagined with the coming of the IoT, Internet of Things evolution. The value of these systems is reduced response time, labor costs, better-operating efficiencies, and minimize waste of materials. Real time data is now the standard for the communication protocols and process controls.
Newer “SCADA” systems include devices that touch every part of our lives including.
Location of System is Key Factor. Not all of the listed applications include exposure to extreme weather, but many of them are in remote locations. From this list, most of us can imagine the extreme conditions that these automated, mostly computerized systems operate in during their lifetime.
Now the communication channels include Wifi, bluetooth, glass fiber, satellite, microwave, and wireless networks.
With communications and the ability to transfer massive amounts of data simply and cost effectively SCADA systems have grown dramatically. Newer systems don’t require the large industrial electronic enclosure of the past but still require some level of environmental controls to protect the sensors and other electronics from adverse weather conditions.
How Do SCADA Systems Work?
Modern systems use a myriad of sensing devices to collect data from the operating systems. This information is collected and accumulated for transmission at the remote location by data acquisition software and computers.
Depending on the network, some of the data is recorded & processed at the remote site. In other systems, all the information is sent back to a central monitoring and control station.
With either case, preprogrammed parameters in the operations will indicate alarm conditions or requirements for adjustments of valves or other actuators. When the error or fault condition occurs, a signal is sent locally or from the central station to make necessary adjustments to the controlling devices.
How Are SCADA Systems Designed for Extreme Conditions?
Industrial applications that require remote sensing are often located in inhospitable locations as diverse as desert, northern regions, and the bottom of the ocean. Even the top of a building in Chicago temperature could reach 60 degrees below zero wind chill during the winter months.
Larger remote cabinets and enclosures have room for climate control equipment. Smaller enclosures like traffic lights, security cameras, drones, robots, and satellites don’t have the luxury of space for environmental controls.
All these systems are housed in environmentally designed enclosures but often require special considerations for their location. See our previous post on “Condensation in Electronic Enclosures” or “Immersion Heaters.”
PTC heating elements for SCADA.
Ceramic PTC heating elements are uniquely suited for controlling temperature and humidity in small enclosures used for housing SCADA equipment. Due to their small size, high watt density, durability, and self-controlling characteristics they are an ideal choice for maintaining desired temperatures and humidity.
PTC stands for positive temperature coefficient. This means that the device has a direct relationship between temperature and the amount of current flowing through it for heating. As its temperature increases its resistance increases proportionally reducing the current flow and maintaining a set temperature range.
The device is a closed-loop system without the requirement of external sensors or controls decreasing complexity and space requirements in an enclosure.
Types of PTC heating elements for enclosures.
The size of remote panels housing electronics vary considerably with the type of application and location. PTC heating element devices are made in a variety of configurations to meet the needs of most applications.
Thermoelectric Cooling Devices
Applications that also require cooling to maintain the desired climate inside cabinets can use traditional air conditioning and heat pump systems if they have the space and power. This type of cooling that requires periodic maintenance may not be ideal for remote locations.
Where space is a constraint thermoelectric devices may be the answer. The devices work on the Peltier effect which cools due to current traveling through two solid dissimilar materials. Since there are no moving parts no maintenance is required. Plus their durability is a plus in satellites and autonomous vehicles that can’t be serviced easily.
Hydrostats and Condensate Evaporators
Moisture is the number one enemy of electronics contained in SCADA systems. Simply heating and cooling the air in the enclosure may not be sufficient to keep moisture from condensing on the electronic equipment inside.
There is a constant battle with dew points inside the enclosures. Warmer temperatures hold more moisture in vapor form. As the temperature cools below dew point moisture will change from vapor to a solid state on cooler electronic boards or other devices. This moisture or water droplets can cause significant damage to circuits.
Condensate evaporator removes excess moisture.
Condensate evaporators made for enclosures use PTC heater technology for reliability and low power consumption removing condensation before it forms on electronics. These are low maintenance devices that do not require draining or the accumulated water.
Made in a very compact encapsulated design they easily mount on existing DIN rails in enclosures.
Larger cabinets require additional control systems.
Larger control cabinets may require thermostats, hydrostats and temperature sensors to maintain desired conditions throughout complex power, communications, and monitoring equipment.
DBK USA offers a wide range of PTC heating devices to help protect electronic devices from cold temperatures and controls to maintain desired temperatures. Many are off the shelf products that can be ordered online for testing or directly installed into your SCADA systems.