PLC-Ladderladder
11 posts
FBD vs Ladder Logic: Which PLC Language for Which Job
FBD vs ladder logic compared honestly: same underlying logic, different readability. Which language fits interlocks, analog, sequences — and when to mix.
Allen-Bradley Ladder Logic: XIC, XIO, OTE and How Rockwell's Rungs Differ from IEC
Allen-Bradley ladder logic explained: XIC, XIO, OTE, OTL/OTU, ONS, TON and CTU in Rockwell terms, mapped to IEC 61131-3 — for Studio 5000 and RSLogix users.
Why Ladder Logic Can't Loop, and the Four Ways Industry Works Around It
Ladder logic has no FOR loop by design. Why, the four workarounds plants use (AOIs, array instructions, one-per-scan, jumps), and our compiler's approach.
Plain English to PLC Code: How Natural Language Becomes Verified Ladder and FBD Logic
How plain English becomes verified ladder and function block logic: the pipeline from written spec to IEC 61131-3 code, and why verification is the hard part.
PLC Timers Explained: TON, TOF and TP with Ladder and FBD Examples
PLC timers explained: how TON, TOF and TP function blocks work, their IN, PT, Q and ET pins, and real ladder and FBD examples for each timer type.
Ladder Logic for Beginners: Rungs, Contacts, Coils and the Scan Cycle
Ladder logic explained for beginners: rungs, contacts, coils, the PLC scan cycle, series AND, parallel OR, and the seal-in circuit with examples.
Structured Text to Ladder Logic Converter: How It Works (and How to Verify the Result)
How a structured text to ladder logic converter really works (parse, model, render), why hand translation drifts, and what the diagram can and cannot prove about your intent. Worked example: the three-wire start/stop circuit.
Create Ladder Diagrams Online: A Working Circuit in Your Browser in Two Minutes
Why ladder tooling has been desktop-and-licence-locked, what building a ladder diagram online actually changes, a two-minute walkthrough from an English sentence to a running circuit, and when a desktop IDE is still the right tool.
Free Online PLC Simulator: Test Ladder Logic Without Hardware
Test ladder logic in your browser before hardware: how the scan cycle works, what to simulate (seal-ins, timers, interlocks) and a worked conveyor example.
One Rung or Five? How to Count Networks in Ladder Logic
A network is one output, not one condition. The reset-latch example shows why the same behaviour can be one rung or two, and how timers and math count.
What Is a Function Block Diagram? FBD Definition and Basics
What a function block diagram (FBD) is in IEC 61131-3: blocks, pins and wires, how FBD relates to ladder logic, and where each view wins.