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 MoreA PLC programmer does not need to be a chemical engineer, mechanical engineer, process engineer, electrician, instrumentation specialist, and machine designer all at the same time.
But there is another extreme …
Read MoreIn industrial automation, the word alarm is often used for almost everything that goes wrong.
A motor fails to start.
A tank reaches a high level.
A VFD trips.
A communication module disconnects.
An operator …
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 MoreModern industrial automation systems are no longer isolated PLCs controlling a few inputs and outputs.
Today, a machine may interact with PLCs, HMIs, SCADA platforms, historians, databases, MES systems, remote I/O, …
Read MoreWhen working with Allen-Bradley ControlLogix or CompactLogix systems, one of the first architectural decisions a programmer eventually faces is how to handle physical I/O inside the PLC program.
At the beginning, …
Read MoreIn the previous articles, we built an I/O architecture using:
Direct physical I/O
Alias Tags
Individual mapped tags
XIC/XIO and OTE
MOV
COP
CPS
These methods allow us to separate physical hardware from application logic.
But as the machine …
Read MoreThroughout this series, we have explored several different ways to handle I/O in Studio 5000.
We started with the simplest possible approach:
Local:1:I.Data.0
Then we introduced:
Alias Tags
Individual Mapping
MOV
COP
CPS
UDTs
Digital I/O Processing
Analog Scaling
Analog Output Processing
Performance …
What Is a PLC?
A PLC, or Programmable Logic Controller, is an industrial computer used to control machines, equipment, and automated processes.
In simple words, a PLC reads signals from field devices, …
Read MorePLC Addressing: Rack/Slot vs Tag-Based
In a PLC system, every input, output, and internal memory location needs a way to be identified by the controller.
This identification method is called addressing.
In simple …
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