In industrial automation, the words permissive and interlock are often used as if they mean the same thing.
They do not.
Both are conditions that influence whether equipment is allowed to operate, …
Read MoreIntroduction
One of the best ways to improve PLC programming skills is to stop thinking only in terms of individual instructions and start thinking in terms of process behavior, equipment states, …
Read MoreThere is a message becoming increasingly common in industrial automation:
Take a PLC course, learn ladder logic, become a PLC programmer, and start making great money.
There is some truth inside that …
Read MoreA PLC program can work perfectly and still be difficult to troubleshoot.
That distinction matters.
When we first learn ladder logic, the goal is usually simple:
Make the motor run.
Later, the goal becomes …
Read MoreOne of the most useful PLC programming patterns a technician can learn is also one of the simplest:
Trigger → Hold-In → Interrupt
The idea is straightforward.
Something starts the action.
Something keeps it …
Read MoreIn industrial PLC programming, there are often several ways to make the same machine work.
Two of the most common methods for maintaining a control condition are Seal-In logic and Latch/Unlatch …
Read MoreWhen programmers begin learning state machines, two names appear very quickly:
Moore Machine
Mealy Machine
Both are finite state machine models, but they differ in one very important way:
A Moore machine determines outputs …
Read MoreState machines are one of the most powerful programming concepts used in industrial automation.
They are especially useful when a machine can exist in several clearly defined operating conditions such as:
Idle
Starting
Running
Stopping
Opening
Closing
Manual
Automatic
Faulted
Instead …
Read MoreOne of the biggest challenges in industrial troubleshooting is dealing with problems that happen too fast to observe.
A sensor may turn off for only 100 milliseconds. A motor feedback signal …
Read MoreTimers are everywhere in industrial automation.
A motor may need a few seconds to prove that it started. A valve may need time to reach its open position. A photoeye signal …
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