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 Tutorials
Tutorials of Programmable Logic Controller – Learn PLC programs and ladder logic lectures of GE, ABB, Siemens, Allen Bradley, Omron PLC’s.
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
Animation of Electromagnetic Relay
When a voltage is applied to the coil, a current passes through it and this creates a magnetic circuit which
PLC Analog I/O and Network I/O
In the early days of programmable logic controllers, processor speed and memory were too limited to support anything but discrete
PLC Alarm and Trip Documentation
A vast amount of documentation is required for the design and construction of a process facility, which are front-end and
Basics of PLC Programming
In the late 1960’s an American company named Bedford Associates released a computing device they called the MODICON. As an