How PLC Reads the Data from Field Transmitters
Instrumentation and control rely on converting physical or process variables into a more useful format for the operator display. Pressure in a pipe is converted to mechanical deflection of a…
How a PLC do the Scaling for a Sensor ?
I am always surprised how an automation system like PLC or DCS does the scaling for a sensor ? or even sometimes thinking about a simple field transmitter scaling techniques…
DCS versus PLC Architecture
The main difference between DCS and PLC is the business model which we discussed with comparison of DCS Versus PLC Architecture. DCS versus PLC Architecture The DCS business model can…
Difference between DCS, PLC, and RTU ?
One of the most common questions is regarding the difference between DCS and PLC as well as between PLC and SCADA – and if there is any difference at all…
PLC Motor Control Ladder Logic Programming
Now we are discussing about How a PLC Motor Control ?. Before going into the article, let us assume some conditions here. A PLC has to start a Motor when the…
PLC Program for Star Delta Motor Starter
Motor contactors are controlled by using PLC. The following section of PLC tutorial will explain the ladder programming for star delta motor starter.
PLC Example with Switches
For example, the LED in this circuit will turn on if the liquid level rises above 14 inches and the pressure falls below 22 PSI and either the flow is…
What is Seal-in Circuit ?
A Seal-in circuit is a method of maintaining current flow after a momentary switch has been pressed and released. What is Seal-in Circuit ? Fig 1 : Start button not…
What is Interposing Relay in a PLC System ?
Interposing Relay is the auxiliary relay which is used to isolate the two different systems / devices. This could be because they have different 0V references, different voltages, AC vs. DC. Interposing…
PLC Valve Control Ladder Logic Programming
Objective : To understand the basic concept of PLC Valve Control Ladder Logic. Target Users : Students, Technicians, Freshers, Trainee engineers. Note : Barrier or Relay not shown in above…
