Digital I/O devices produce input and output signals from cards, USB modules or other terminals to acquire data. A digital IO uses on and off signals for communication, automation and control of machine equipment or applications. Functions of a digital I/O, when inputting data, include conversion of AC or DC voltages to DC logic signals. The DC logic signals get transferred to a computer system. An output digital I/O turns AC or DC circuits on or off based on computer commands.

Many applications use digital I/O devices for analyzing, controlling and monitoring purposes. For example, USB digital I/O devices only require one connector for computer controls. Other digital IO devices monitor alarms, control timers, industrial processes, test production equipment or are used to examine laboratory materials. Digital I/O boards also apply to automated machines, lamps, digital sensors, remote transducers and motors. Digital I/O cards monitor security systems, field sensors, energy management systems and factory automation. Here are some factors to consider before buying digital I/O systems for your business:

1. Ensure that digital I/O devices meet industry standards.

2. Determine the need for digital I/O devices with one or more connections, inputs and outputs.

3. Find digital IO modules that are cost-effective.

Action Steps
The best contacts and resources to help you get it done

Find digital I/O modules that pass industry standards

When buying digital I/O modules and other devices, be sure that they are certified to operate in business or factory conditions.

I recommend: National Instruments produces digital I/O solutions that are suitable for design, test and control applications. Jameco Electronics manufactures digital I/O devices and other components that exceed industry standards.

Choose digital I/O devices based on need, number of connections and other features

Most digital I/O devices or modules feature short circuit protection, LED displays for effective monitoring of different processes and multiple connections that allow for different capabilities.

I recommend: Advantech manufactures digital IO modules with built-in microprocessors, and digital IO cards with as many as 32 input and output channels. MKS Instruments features a product line of Ethernet-based digital I/O modules.

Look for cost-effective digital IO modules or devices

Shop for digital I/O devices from competing manufacturers to decide which items fit in with your budget.

I recommend: ICP DAS USA distributes remote Ethernet, web-based Ethernet and other data acquisition digital IO modules. Free shipping is also available if ordering within the United States and the total reaches $200 or more. In addition to offering digital IO and other devices at competitive prices, AutomationDirect offers free shipping if order totals are $300 or more. Same-day shipping is also available for most of their products.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Power requirements, user connections, circuit voltage, operating temperature range and relative humidity range should be some of the top specifications to watch for when picking digital IO devices.
• •  Most digital I/O devices are certified by Underwriters Laboratories, the Consumer Electronics Association and the Canadian Standards Association.