Installation of VFD Careful planning of your VFD installation will help avoid many problems. Follow the instructions from the VFD manufacturer for required and optional installation requirements. Important considerations include temperature and line power quality requirements, along with electrical connections, grounding, fault protection, motor protection, and environmental parameters. Selecting the Drive In selecting a drive, …
Operation of VFD The primary function of any electronic adjustable-speed drive is to control the speed, torque, acceleration, deceleration, and direction of rotation of a machine. Unlike constant-speed systems, the adjustable-speed drive permits the selection of an infinite number of speeds within its operating range. The use of adjustable-speed drives in pump and fan systems …
Operation of DC Drives DC drive technology is the oldest form of electrical speed control. The speed of a DC motor is the simplest to control, and it can be varied over a very wide range. DC electronic variable-speed drives vary the speed of DC motors with greater efficiency and speed regulation than resistor control …
PLC Data Communication System Data communications refers to the different ways that PLC microprocessor-based systems talk to each other and to other devices. The two general types of communications links that can be established between the PLC and other devices are point-to-point links and network links. Figure 1 illustrates a point-to-point serial communications link. Serial communications …
Process Control Systems Types of Processes: Process control is the automated control of a process. Such systems typically deal with analog signals from sensors. The ability of a PLC to perform math functions and utilize analog signals makes it ideally suited for this type of control. Manufacturing is based on a series of processes being …
Troubleshooting of PLC In the event of a PLC fault, you should employ a careful and systematic approach to troubleshoot the system to resolve the problem. PLCs are relatively easy to troubleshoot because the control program can be displayed on a monitor and watched in real time as it executes. If a control system has …
Installation and Commissioning of PLC A PLC system, if installed properly, should give years of trouble-free service. The design of PLCs includes a number of rugged features that allow them to be installed in almost any industrial environment. However, problems can occur if the system is not installed properly. Programmable logic controllers (PLCs) require protection …
This article explains how the PLC shift register functions operate and how it can be applied to control problems. Shift registers are often used to track parts on automated manufacturing lines by shifting either status or values through data files. PLC Shift Register Instructions & Programs The PLC not only uses a fixed pattern of …
PLC Sequencer Instructions This article explains how the PLC sequencer functions operate and how they can be applied to control problems. The sequencer instruction evolved from the mechanical drum switch, and it can handle complex sequencing control problems more easily than does the drum switch. Mechanical Sequencers Sequencer instructions are designed to operate much like …
Most PLCs have arithmetic function capabilities. Basic PLC math instructions include add, subtract, multiply and divide to calculate the sum, difference, product, and quotient of the content of word registers. The PLC is capable of doing many arithmetic operations per scan period for fast updating of data. This article covers the basic mathematical instructions performed …
