Meeting the Challenges of EMI Control and Safety in Compact Industrial Control Panels

Industrial network control panel designers face significant challenges when managing electromagnetic interference (EMI) and ensuring operator safety in increasingly compact installations. That requires careful planning and component selection to balance a small footprint with operational needs and regulatory requirements.

Safety is a key demand. However, the safety requirements for control panels can vary across different locations within an industrial network. Hazardous environments have stricter safety needs compared with more benign locations. That requires network designers to deploy a variety of different safety solutions.

Similarly, for environmental ruggedness and controlling EMI, devices must be specified and selected based on ratings that consider mechanical, ingress, climatic/chemical, and electromagnetic (M.I.C.E.) attributes, taking into account the specific needs of individual installations. That includes control panel wiring solutions, such as ducting, that shield sensitive wiring from noise emissions and deliver up to 20 dB of noise reduction, along with 90% noise voltage reduction.

There are also varying levels of ingress protection (IP ratings) required for different installations. Compact, LED lights are often included for general illumination and to clearly indicate the status of machines and control panels to operators at a glance.

This article examines various control panel products from Panduit and Banner Engineering, both inside and outside the control panel, that designers can utilize to optimize control panel configurations, minimize panel size, and simplify integration without compromising performance.

Network designers require a range of safety solutions. Banner Engineering’s SC10 and XS26-2 safety controllers both meet the requirements of ISO 13849-1 and IEC 61508 by supporting safety functions in programmable industrial systems. They are optimized for different types of applications.

Some important differences between the SC10 and XS26-2 safety controllers are their scalability, number of I/O points, and communication options. The SC10 is a compact, cost-effective device ideal for smaller applications, while the XS26-2 is an expandable system for more complex machine and operator safeguarding.

The compact SC10 series safety controllers are designed to replace two or more safety relay modules in tight spaces. They may be small, but they are mighty in terms of capability. The in-series diagnostics (ISD) provides detailed status and performance data for up to 70 connected safety devices. The data is accessible via a human-machine interface (HMI), programmable logic controller (PLC), and other similar devices, or can be sent to the Cloud.

SC10 controllers are highly flexible and support a wide range of safety devices. The icon-based programming interface, with drag-and-drop configuration using a personal computer (PC), speeds setup and ongoing management. They can also be configured and programmed without a PC using an external memory card.

They have ample I/O, including two safety relay outputs rated 6 A each, with three normally open (N.O.) sets of independently controlled contacts. The ten inputs include four that can be configured as non-safe outputs. Banner’s automatic terminal optimization (ATO) feature enables users to convert standard inputs into non-safe outputs or vice-versa, increasing the number of available inputs from 10 to 14.

Connectivity is another key strength of SC10 controllers. The industrial Ethernet interface can support 256 virtual non-safe status outputs and 80 virtual non-safe inputs. These safety controllers also provide Ethernet/IP, PROFINET, and Modbus/TCP protocols for connection to a wide array of devices.

Figure 1: This SC10-2ROE safety controller features 10 configurable safety inputs, two 6 A, 3-channel safety relay outputs, and supports ISD for real-time status and error data. (Image source: DigiKey)

For more complex installations requiring larger numbers of I/O, designers can turn to Banner’s SX26-2 series of expandable safety controllers. They have many of the same basic features as the SC10 series and support a wider array of industrial Ethernet communication protocols, including EtherCAT, EtherNet/IP, Modbus/TCP, programmable controller communication commands (PCCC), and PROFINET.

The base SX26-2 controller can connect with up to eight I/O expansion modules, allowing it to adapt to larger, more complex applications as machinery or automation requirements grow. In addition to supporting connectivity to a PC, these controllers feature an integrated display for real-time monitoring of I/O status, a crucial feature in complex control networks.

Controlling cabinet access

Once an industrial control network is up and running, there are times when it’s necessary to access devices inside the control cabinet. Panduit has two options for industrial network designers: data access ports that support external connections to devices inside the cabinet, and VeriSafe absence of voltage tester (AVT and AVT2) devices that automate and simplify the process of absence of voltage verification testing (Figure 2) before opening the cabinet for direct access to devices inside.

Figure 2: Panduit VeriSafe ATV2 is suitable for Class 1/Division 2 hazardous locations, as it is free of voltage testers. (Image source: DigiKey)

The data access ports enable service technicians to connect to the devices inside the control cabinet externally. The flexible modular design allows for the interchange of RJ45 jacks, circuit breakers, USB ports, and other connectors at any time. They meet numerous standards, including UL, CSA, and NEMA, and comply with IP65 as defined in IEC 60529.

VeriSafe absence voltage testers ensure technician safety when it’s necessary to service devices inside a control cabinet. A lighted push button provides a visual indication that it’s safe to open the cabinet. The system meets the ISA 12.12.01 and CSA C22.2 No. 213 standards, as well as the reliability requirements of SIL 3, in accordance with IEC 61508.

M.I.C.E. and EMI in the network

Panduit offers a range of industrial network components that meet the requirements of the TIA-1005-A M.I.C.E. guidelines, including various IP ratings for different locations. Examples of Panduit M.I.C.E. rate products include M12 Cat 5e and Cat 6A cable assemblies, pre-configured network zone enclosures with various ethernet, fiber, power, and cooling options, industrial uninterruptible power supplies rated up to 100 Watts, and modular connector plugs and adapters.

Control panel wiring solutions for EMI control are an essential aspect of designing and installing industrial control cabinets. Panduit offers a variety of wiring duct and shielding solutions:

• Panduct PanelMax DIN rail wiring ducts are compatible with standard 35- or 15-mm rails.
• Panduct PanelMax corner wiring ducts utilize otherwise unused vertical corner space in enclosures, reducing the overall wiring footprint.
• Panduct PanelMax shielded wiring ducts are available in 2”, 3”, and 4” heights to accommodate various wiring needs. The hinged cover remains attached during maintenance and upgrades, preventing lost covers and acting as a ledge to aid wire installation. Model DRD22LG6 is 2” high (Figure 3).
• Panduct PanelMax noise shield, like the 2” high model SD2EMI, can be used separately or mounted within a wiring duct and provides up to 20 dB noise reduction and 90% noise voltage reduction (up to 6" air space).

Figure 3: Panduct PanelMax shielded wiring ducts provide effective EMI shielding for sensitive applications. (Image source: DigiKey)

Monitoring internal temperature and humidity

Monitoring temperature and humidity conditions in the tight internal space of a control cabinet or machine can be challenging. However, it’s essential to maintain high levels of reliability. The compact S15S IO-Link sensor from Banner Engineering fits this need and takes it one step further by monitoring dew point in addition to temperature and humidity.

The S15S uses information from its temperature and humidity sensors to calculate the dew point. Its compact design and IO-Link connectivity make it suitable for installation inside crowded control cabinets or machines.

Users can select specific data points for temperature, humidity, and dew point that are reported by the sensor. Those device parameters can be adjusted on the fly to support different products or operating conditions. Integrated diagnostic capabilities include device status, warnings, and errors.

Illumination + indication

Lighting can be an underappreciated and therefore an underutilized aspect of industrial machine design. Correctly integrated, using LEDs, it can provide task illumination, multiple color performance indicators, and warnings.

A single, multipurpose lighting device can save space and improve visual network management. Some multicolor LED lighting units are flexible and can be installed on curved surfaces. Banner offers thousands of lighting options, providing designers with great latitude when customizing and enhancing the machine's appearance and visual performance.

Some of the numerous options include multicolor tower lights, lights that include integrated pushbutton switches that light up in different colors to indicate system status, and lights with integrated segmented displays to quantify important performance parameters. Other options include the WLS27 Series LED bar task lights that serve double duty as white task lighting and have multicolors for status indication along with the WLF12 Pro flexible multicolor strip lights that can be mounted on curved surfaces (Figure 4).

Figure 4: A sampling of the thousands of industrial illumination and indicator solutions offered by Banner Engineering. (Image source: Banner Engineering)

Conclusion

By leveraging the combined comprehensive offerings of Banner Engineering and Panduit, industrial network designers can develop compact, high-performance control panels, industrial networks, and machines. Whether the need is operator or machine safety, EMI control, visual network management, environmental monitoring, or other functions, industrial network designers can turn to solutions from Banner Engineering and Panduit at DigiKey.

Recommended reading:

1. Applying a Holistic Approach to Integrated Factory Automation
2. How to Quickly Design and Deploy IIoT-Ready Machines
3. Deploying Predictive Maintenance for the Maximum Benefit in Industry 4.0 Facilities
4. How to Specify Cables to Ensure Success in Extreme Environments
5. Designing Control Panels for Safety and Maintainability