What is Ladder Diagram Programming ?
Ladder Diagram (LD) Programming The most common language used to program PLCs is Ladder Diagram (LD), also known as Relay
Basics of Fail-safe Circuits
Logic circuits, whether comprised of electromechanical relays or solid-state gates, can be built in many different ways to perform the
History of Programmable Logic Controllers (PLC)
Every control system may be divided into three general sections: input devices (sensors), controllers, and output devices (actuators). The input
PLC Electric Motor Interlocks
Programmable Logic Controller Questions and Answers The following PLC program was written to control the operation of a large electric
PLC Data Comparison Instructions
As we have seen with counter and timers, some PLC instructions generate digital values other than simple Boolean (on/off) signals.
PLC Math instructions
The IEC 61131-3 standard specifies several dedicated ladder instructions for performing arithmetic calculations. Some of them are shown here: PLC
PLC Timer Instructions
A timer is a PLC instruction measuring the amount of time elapsed following an event. Timer instructions come in two
PLC Counter Instructions
A counter is a PLC instruction that either increments (counts up) or decrements (counts down) an integer number value when
PLC Memory Mapping and I/O addressing
A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC they
What is Human Machine Interface (HMI) ?
Programmable logic controllers are built to input various signal types (discrete, analog), execute control algorithms on those signals, and then