Monthly Archives: March 2016

Ladder logic 402: Data manipulation and filtering

The prior post on ladder logic discussed using a programmable logic controller (PLC) to capture values from an analog card. Once those values have been captured, there are methods to filter the data and methods to simulate a filter using Microsoft Excel before it is coded into a PLC. There are several filtering algorithms that can be found on the Internet currently being used on a PLC (see links below). For the formulas, the same variable names were used even though they differed extensively in the various posts: N = New value calculated and substituted for the input value. In other words, the calculated filtered value. L = The previous captured input value. F = The previous calculated filtered value. k = The manipulated factor for all calculations (sometimes known as Alpha). i = The current analog input value. Avg = A running average over x number of previous samples,


Interface for lean image processing, data transfer

Basler’s BCON interface enables the lean image processing through flexible and cost-saving attributes while connecting to technology that is based on low-voltage differential signaling (LVDS). While LVDS describes a standardized interface for high-speed data transfer, BCON ensures image data transfer and offers flexibility. In addition,

Wirelessly-monitored storage tank safety valves

Emerson Process Management’s Enardo 850/950 series of wirelessly-monitored pressure vacuum relief valves (PVRVs) are designed to provide safety and emissions control by managing the pressure in storage tanks in the oil and gas, chemical, petrochemical, and pharmaceutical industries. The pressure in storage tanks fluctuates due to changes in temperature, liquid level, or both. The Endrdo 850/950 series opens and closes in response to these pressure fluctuations to ensure that safe pressure levels are maintained. However, because these PVRVs are located on the top of storage tanks, they are difficult to monitor. The Enardo series is designed to enable immediate response to prevent problems related to safety, emissions, and the quality of a tank’s content. Emerson Process Management

Top 5 Control Engineering articles, March 21-27: PC-based control, Engineers’ Choice winners, heat exchanger control strategies, more

The top 5 most read articles online, from Mar. 21-27 for Control Engineering covered PC-based control, the 2016 Engineers’ Choice Awards winners, heat exchanger control strategies, ladder logic and PLC scanning, and data acquisition and analysis. Link to each article below. 1.

Pressure switch for industrial, OEM applications

The Ashcroft B7 NEMA 7/9 pressure switch is designed for industrial and OEM applications. The 7/9 switch is explosion-proof and has a fixed or limited adjustable deadband and an external locking screw. It is ideal for satisfying requirements for pressure control, safety shutdown or alarm operations in hazardous applications. These switches are IP66-rated and are approved for use in most NEC Class I and II hazardous locations. Each pressure switch can be fitted with a variety of diaphragm materials (including Monel for NACE applications) or with an external diaphragm seal to resist caustic or corrosive media. It has a single-setpoint and pressure ranges to 3,000 psi. Ashcroft