The use of measuring devices to monitor and control processes is critical to the smooth operation of large systems, and it is an integral part of the future of the Internet of Things. Considerations include fiber optics, IP ratings, connector materials, and more.
Seven Essentials for Rugged Connectors in Instrumentation Applications
The use of measuring devices to monitor and control processes is critical to the smooth operation of large systems, and it is an integral part of the future of the Internet of Things.
Obviously, there is no sense in measuring to the “nth” degree if you can’t get the information to the right place at the right time. That means choosing the right connector and the right interconnect solution. With thousands of standard connector configurations and customized connector and cable assembly solutions available, you absolutely must consider these details early in the design phase to help you choose the best solution. Focus on finding the right solution early to improve the design, usability, and cost structure of your instrumentation device. Accuracy and long-term performance with good product durability will be the result.
Understand the details behind the IP ratings and compare them to your application needs.
Many instrumentation applications call for IP Code (ingress protection) of at least IP68. These ratings classify the degree of protection provided against intrusion, dust, accidental contact, and water by mechanical casings and electrical enclosures. What many people miss is that not all IP68 ratings are created equal. The fact is, each supplier can define what IP68 means to its product.
Many manufacturers define IP68 as two meters for 24 hours. Others define it as robust as 120 meters for 48 hours or as easy as 1.5 meters for two hours. Look closely at the manufacturer’s testing information. There is a big difference, so be sure that you know exactly what level of protection you need for your instrumentation application.
Explore your connector materials for best price/performance.
When designing a measuring device, engineers find that many different materials are suitable for connectors; the choice depends on the specific application. Each material has advantages and disadvantages. Applications near salt water or that require extended exposure to the elements will require nickel-plated brass. Aluminum is a great material for handheld applications with weight concerns when the connections are not exposed to the elements for a long time. Plastic can be used in high-voltage applications because it may provide a degree of protection to the user. If your application is in a corrosive environment where the connector might come into contact with chemicals, you’ll want the connectors to be made of stainless steel. Stainless steel is more expensive than brass or aluminum, but some applications demand connectors that can withstand the most extreme conditions, such as a connector that needs chemical or nuclear decontamination/sterilization.
Select your cable and cable material.
When choosing cable for instrumentation, design engineers must again consider the end use of the device. Make sure that the cable type meets your voltage and power levels and is designed for the type of signal(s) it will carry. Field-deployed applications require greater tensile strength than standard commercial cables to make sure they can withstand the rugged environment. For accuracy, the cable must be properly shielded to prevent any hint of interference; a rugged jacket withstands abrasion. Thermoplastic jackets and connector overmolds have great insulating properties and are appropriate for most instrumentation applications. The material is highly flexible and provides resistance to liquids and chemicals and provides good abrasion resistance.
Look into fiber optic benefits.
Rugged fiber optic connectors are a great choice for long-term monitoring situations that require moving a high volume of data over a great distance. Fiber optic cabling and connectors are a lightweight, secure way to install a fast and reliable data link. As with copper cables, be sure to test connectors with the specified cable to make sure that the solution works with your equipment.
For applications where multiple mating cycles are typical, such as a temporary setup at a sporting event, look for fiber optic connectors that are field-cleanable. Some fiber optic cables also provide power and fiber in a single connector.
Fiber optics are also used in sensing applications to gather information about the environment, using the physical interaction of light along the fiber. This technology can be used for acoustic, strain, thermal expansion, or temperature measurement. For example, in oil drilling monitoring applications, sensing instrumentation allows real-time information about the geological properties being drilled due to the sound that is produced. Engineers can evaluate the information and make adjustments to the process.
Fiber optics is also the best candidate to carry data over large distances and can be an easy way to build an Ethernet network between locations further than one mile apart.
Take advantage of hybrid connectors whenever you can.
Hybrid connectors can reduce the complexity that often comes along with your customer demands for increased functionality. Mixing signal and power, coax and signal, and mixed signals are common requests. Even fluid and signal hybrids are possible as customized solutions, although they may require longer lead times.
Power mixed with fiber optic can also reduce the number of connections required. The benefits of mixed functionality in connectors include better usability, less overall weight, and lower overall component costs.
Get small, but not so small that you can’t easily connect and disconnect.
Of course, we all want a smaller device and a smaller connector, but getting too small can be an issue, especially if the user is wearing gloves. Look for connectors that are dense without creating interference. Make sure you examine the details, including pin size, especially if you are running power. Many of the smallest connectors are designed only for signal.
If you connect and disconnect frequently, look for a mini connector that has up to 5,000 mating cycles. And of course, the connectors have to be sealed to withstand dirt, grime, and weather when instrumentation devices are outside in the elements.
Checking networking protocols.
Instrumentation applications often demand the transmission of a high quantity of data in real-time or near real-time. Many rugged connectors are built for fast data transmission, including industry-standard networking protocols and USB speeds.
Keep in mind that the connector is only one contributor to the performance of the cable assembly; be sure to consider the cable quality, process, and length. Test your data rates and protocols with the connector and cable together. The connector and cable may pass tests individually but should be considered together to ensure reliable performance.
By Earl Kneessi, Sales Engineering Manager, Fischer Connectors Inc.