IO module replacement advice: Consider documentation, controllers, application

I/O wiring can be among the most challenging (and perhaps feared) of upgrades. When replacing input/output connections, what are key considerations? Jason Haldeman, Phoenix Contact product marketing lead specialist for I/O, offered answers to some key questions.


Machine-mount IP67 I/O will initially cost more than IP20. However, thanks to the ease of installation and the potential for reducing the number of cabinets, it can save money in the long run. Courtesy: Phoenix ContactControl system wiring, at input/output (I/O) connections, can be among the most challenging (and perhaps most feared) of upgrades. When replacing I/O connections, what are key considerations? Jason Haldeman, Phoenix Contact product marketing lead specialist for I/O, offered answers. When replacing or upgrading I/O modules, consider documentation, controllers, application needs, and support.

Q: Control Engineering: Is there documentation?

A: Jason Haldeman, Phoenix Contact product marketing lead specialist for I/O: Good documentation is very important at all stages of I/O installation. You count on documentation to help with the upgrade. If you don’t know what you have, it will be much more difficult to upgrade your connections. Your supplier should have all the proper supporting documentation to simplify the I/O installation.

CE: What network protocols are required and will they be wired, wireless, serial, digital, or a combination?

Haldeman: Choosing the desired bus network is very dependent on the PC/PLC used in your current system. These suppliers provide interfaces to specific networks, limiting your options and locking you into specific networks. Moving away from their PC/PLCs would require rewriting your entire control program. For this reason most people stick with what they are comfortable programming, dictating what I/O network they use (for example, DeviceNet, Profibus, Interbus, Modbus RTU, EtherNet/IP, Profinet, and Modbus/TCP). Most new application are moving to Ethernet protocol, providing greater flexibility to incorporate options like redundancy and wireless.

CE: What functionality do attached applications need to integrate? What types of signals (analog, digital, serial, mixed...), what units (current, volts, resistance, AC, DC...), what range, and how many channels are needed? What are the sensing, signal conditioning, distributed control, isolation, and other requirements?

Haldeman: Questions like this make it very important for you to select an I/O provider that meets the flexibility your application demands. Your provider should be able to supply you with a wide, modular range of inputs, outputs, special functions, integrated wireless communication, and connectivity to fieldbus and industrial Ethernet networks. On top of your I/O needs, the supplier should be able to supply all the supporting components, such as power supplies, Ethernet switches, and terminal blocks.

CE: Will the application expand and by how much?

A variety of input/output modules are available in the Phoenix Contact Inline and Fieldline I/O systems for IP20 control panel use or for an IP67 machine mount application. Phoenix Contact Inline Block IO are shown. Courtesy: Phoenix ContactHaldeman: Modular I/O systems allow the user to custom-configure an I/O station to meet their exact application needs. In the future, if you need more I/O, you simply purchase additional I/O points and attach them to your existing I/O station.

CE: Will the I/O connections be enclosed or exposed?

Haldeman: This is a very important part of your decision-making. Do you use IP20 I/O inside a cabinet or lose the cabinet and go with IP67 I/O mounted directly on the machine? IP67 I/O initially costs more, but saves you with ease of installation and the cost saving of not having as many cabinets.

CE: What are among the most-overlooked considerations?

Haldeman: Support is a topic that is always overlooked until it is needed. Your I/O provider needs to be able to supply the necessary support functions to assist with questions during the installation of the I/O modules.

- Jason Haldeman, Phoenix Contact product marketing lead specialist for I/O, and Mark T. Hoske, CFE Media, Control Engineering,

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Sister act: Building on their father's legacy, a new generation moves Bales Metal Surface Solutions forward; Meet the 2015 Engineering Leaders Under 40
2015 Mid-Year Report: Manufacturing's newest tool: In a digital age, digits will play a key role in the plant of the future; Ethernet certification; Mitigate harmonics; World class maintenance
2015 Lubrication Guide: Green and gold in lubrication: Environmentally friendly fluids and sealing systems offer a new perspective
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security
Cyber security attack: The threat is real; Hacking O&G control systems: Understanding the cyber risk; The active cyber defense cycle
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Building high availability into industrial computers; Of key metrics and myth busting; The truth about five common VFD myths
New industrial buildings: Greener, cleaner, leaner; New building designs for industry; Take a new look at absorption cooling; Offshored jobs start to come back

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.