Industrial Automation

PLC teardown

PLCs have a long and storied history, with Allen-Bradley itself coining the term “programmable logic controller” in 1971 when it introduced its version of what was then called the “programmable controller.” For anyone who cut their teeth on ladder logic can testify, PLCs at the time were an elegantly simple solution to an age-old problem:

Arduino PLC

The PLC (Programmable Logic Controller) has been and still is the basic component of the industrial automation world. PLCs are usually pretty expensive pieces of hardware, which led many people who know micro-controllers to come up with their own ideas to implement similar functionality. Arduino is a kind of universal programmable controller, although it is

Ethernet in sensing

In the modern world sensors are used for recording everything from exhaust gas temperatures to the electrical activity in a human heart. Direct wiring methods are commonly used for simple on-off device control, where a circuit is either open or closed. Likewise, digital sensors are usually wired directly to monitoring panels in the world of

Automation systems security issues

Supervisory Control and Data Acquisition (SCADA) systems are used for remote monitoring and control in the delivery of essential services products such as electricity, natural gas, water, waste treatment and transportation. They used to be in closed networks, but nowadays more and more automation and control equipment are connected to Internet. Many of them are

Understanding grounding, shielding, and guarding

Inadequate shielding and bad grounding are often blamed when measurements are inaccurate, especially in high-impedance applications. Understanding grounding, shielding, and guarding in high-impedance applications article tells tells that in fact, shielding and grounding problems are frequently responsible for measurement errors, but many test system developers aren’t quite sure why. Many measurement errors can be traced

Grounding and EMI

One of the most common direct coupled noise sources is when the ground which is being used for reference or return is not referenced to earth as expected. This is especially prevalent in sensitive high-gain circuits. Grounding and Shielding Existing Equipment – How to effectively minimize EMI issues when best practices are not available is

How to protect RS-232 serial connections

How to protect RS-232 serial connections article pointed me to a recent white paper from APC-Schneider Electric that explains specific power protection issues related to RS-232 cabling. The Protection of RS-232 Serial Connections document contends that the RS-232 port often represents the “Achilles heel” of computer installations which are otherwise well protected by UPS systems