Articles - PLC Programming & Automation

PLC Safety Interlock: Dual-Channel E-Stop on GuardLogix

September 12, 2026January 29, 2024 by PLC

Timing chart of a dual channel E-stop: channel A opens, channel B follows shortly after inside the discrepancy time, the safety output drops at once, the E-stop is released, and the output only returns after the reset button is pressed and released

When a standard interlock is not enough, how to wire and configure a dual-channel E-stop on GuardLogix safety I/O, and the reset rule nobody may break.

PLC Lean Manufacturing Data: OEE, Downtime Codes and SPC from the Controller

September 13, 2026January 28, 2024 by PLC

Ladder rung with four contacts, Auto examined on, Fault, Starved and Blocked examined off, driving the Running output coil that feeds the availability run timer

How a PLC state model feeds OEE, downtime reason codes and SPC triggers on a rotary filler: the ST block, the tag structure and the classic mistakes.

PLC Simulation and Virtual Commissioning: A Working Setup

September 13, 2026January 26, 2024 by PLC

Timing chart of a simulated conveyor: the run command, the simulated photoeye going true three seconds later, and the drive feedback reaching the speed reference

Build a Logix Emulate chassis, run PLCSIM Advanced, test the HMI offline, and learn which parts of a machine you can trust a simulation to prove.

PLC Chemical Process Control: BPCS, SIS and Interlocks

September 13, 2026January 24, 2024 by PLC

Timing chart of a reactor high temperature trip: two of three jacket thermocouples vote high, the SIS trip relay trips, the feed valve closes and the quench valve opens

How the BPCS, the SIS and the package PLC split the work on a batch reactor, with a cause and effect matrix, cascade temperature control and IS barriers.

PLC Oil and Gas: Wellhead RTUs, ESD Logic, Tank Farms

September 13, 2026January 24, 2024 by PLC

Ladder rung for a wellhead ESD permissive: reset push button sealed in, high pressure and high level switches healthy, emergency stop normally closed, driving the SDV permissive coil

Wellpad controller choice, an ESD permissive rung that will not auto restart, Modbus poll budgets over radio, flow computers and tank farm level control.

PLC Automotive Manufacturing: Station and Line Logic

September 13, 2026January 23, 2024 by PLC

Ladder rung releasing a body from an assembly station: body present, torque batch complete and vision result OK in series, with a normally closed contact for the downstream station blocked, driving the release output

Station and line PLC split, a PackML state machine in Structured Text, torque tool error proofing, andon stops and downtime that blames the right station.

PLC Sustainable Manufacturing: Measure, Then Shut Off

September 13, 2026January 23, 2024 by PLC

Timing chart of idle shutdown and staggered restart: part flow stops, the idle timer completes five minutes later, the conveyor, vacuum generator and extraction fan switch off in sequence, and when parts return the fan starts first, then the vacuum, then the conveyor

Meter energy, air, water and scrap per part, write idle shutdown in Structured Text, stagger the restart, and report numbers that survive an audit.

PLC vs DCS Programming: Where the Two Part Ways

September 13, 2026January 22, 2024 by PLC

Timing chart of an analog HI alarm: the process value crosses the limit, a three second on-delay expires, the alarm goes active and stays unacknowledged until the operator acknowledges it, then clears when the value returns below the limit

PLC vs DCS programming compared by an engineer who works on both: tags and rungs against loops and blocks, redundancy, alarms, batch and real cost.

Rockwell PLC Software: Which Tool for Which Controller

September 13, 2026January 22, 2024 by Admin

Ladder rung drawn in Studio 5000 notation: XIC Start sealed in by an XIC Motor branch, XIO Stop in series, OTE Motor as the output

A working map of Rockwell PLC software: Studio 5000 editions, RSLogix 500, RSLinx Classic against FactoryTalk Linx, View ME and SE, Emulate and firmware.

PLC Pulp and Paper: Draws, Consistency, Winder Tension

September 13, 2026January 22, 2024 by PLC

Timing chart of a sectional drive ramp: master run starts, wire, press and dryer sections reach reference in turn, and draw trim is only enabled once the whole line is at reference

Sectional drive draws on a paper machine, the ratio calculation in ST, consistency and basis weight loops, and winder taper tension that holds.

PLC Data Logging and Remote Monitoring: Practical Rules

September 13, 2026January 22, 2024 by PLC

Timing chart comparing periodic and change based logging: a one second sample tick, a deadband window where the process value is moving, and the six rows actually written to the database

PLC data logging that stays useful: sampling rates, retention math, a ring buffer in the controller, FactoryTalk datalog, SQL logging, safe remote access.