Connecting plant power to DeltaV

Three-phase floating power for marine applications

The power and grounding practices in this article have been established over decades to provide excellent protection against electrical surges and transients in industrial installations. The electrical system installation must meet the local area codes and regulations to insure personnel safety and protection of property. The most common methodology is based on a solidly grounded … Read more

Emerson DeltaV I/O Sub-system Redundancy

Redundant I/O Card Types Redundant card types and terminations include: • Analog Input (AI) 8 channel 4-20mA with Hart • Analog Output (AO) 8 channel 4-20mA with Hart • Discrete Input (DI) 8 channel 24VDC Dry Contact • Discrete Output (DO) 8 channel 24VDC High-side • Serial Interface card 2 ports • FOUNDATION fieldbus H1 … Read more

Pump control with two pumps using Structured Text (ST)

Pump control with two pumps

This example describes a pump control with two pumps and three float switches in a well. The float switches are attached to cables and when the liquid rises in the well, the float switches will be activated and change their NC / NO position. The two submersible pumps M1 and M2 have been set to alternate operation mode, which … Read more

Simulation signals generated using Structured Text (ST)

Sine wave

This chapter describes simulation signals, which can be used during development and testing of the programming code. The machine or the hardware panel is often not available, when the PLC code and program needs to be tested. The hardware has possibly not arrived onsite, the machine is not built yet, or the PLC equipment is … Read more

Simple queue structure with Structured Text (ST)

ARRAY

This example describes the simplest implementation of a queue. A queue is used when e.g. there are many packages on a conveyer belt, waiting for treatment by a machine in a large plant. The packages often require information like weight, receiver, size or content. Weight gives information about a package which must be saved in … Read more

How the PLC executes PLC code ?

The basic mode of operation for a PLC

It is important to know how the PLC executes the program code when writing the program. A PLC executes the program in real-time, which means that the program modules must be executed within a short time-frame. The program modules are executed at a fixed time interval (the PLC scan time) e.g. 50 [ms]. Some of … Read more

Detailed Design of High Performance Displays

Schematic Example of a Level 3 Compressor Display

Many example depictions are shown conceptually and schematically because there is such wide variation in the display capabilities, characteristics, and arrangement paradigms of specific DCSs. There are major differences between DCSs regarding such commonplace things as controller faceplate access and display. It is the concepts and principles that are important, which are then applied to … Read more

Basic Principles for High Performance HMIs 3

Progressive Exposure of Controller Detailed Functionality

Alarm Access A High Performance HMI is designed to minimize the number of keystrokes required to identify, verify, assess, and respond to an alarm. Every point with a configured alarm should have an associated Level 2 or 3 graphic display on the DCS. This associated display should aid the operator in the proper diagnosis and … Read more

Basic Principles for High Performance HMIs 2

Example Practices for Vessel Levels

General Considerations for Displays There are many graphic design principles common to all displays, regardless of their level in the hierarchy. These common principles are covered in the following sections with examples. In the next chapters, the detailed considerations for content of each display hierarchy are covered. Use of Color Color perception is a highly … Read more

Basic Principles for High Performance HMIs 1

Display with Access to the Relevant Process Controllers

Overview Much has been learned over the last 20 years regarding good and bad industrial HMI design practices. What we now know to be good design practices have come from a variety of sources, including: HMI deficiencies made apparent by accidents, with resulting in-depth analysis Information from academic research. Information from research by other industries … Read more