Articles
Longer-form technical writing, published as it is finished and revised as field experience corrects it. Every entry carries its published and updated dates.
29 entries
Wet Well Level Control
The measurement that runs a lift station: choosing setpoints, protecting the pumps, validating the signal, and the failures that flood a station.
9 min readUpdated Aug 30, 2026
4-20 mA Current Loops
Why the industry standardized on current instead of voltage, how a two-wire loop is powered, what the live zero buys you, and how to read a loop with a meter.
12 min readUpdated Aug 29, 2026
Water and Wastewater Utility Threat Landscape
What has actually happened at water utilities, what those incidents had in common, and the small number of controls that would have prevented most of them.
8 min readUpdated Aug 28, 2026
Duplex Lift Station Controls
The two-pump station that makes up most of a collection system: what is in the panel, how the sequence works, what is monitored, and where these stations actually fail.
11 min readUpdated Aug 27, 2026
OT Security vs IT Security
Why the familiar security priorities invert on a plant floor, and what that changes about patching, scanning, authentication, and incident response.
8 min readUpdated Aug 26, 2026
UL 508A Industrial Control Panels
What the listing actually covers, what has to appear on the label, and the requirements that most often cause a panel to fail inspection.
9 min readUpdated Aug 25, 2026
How to Program Lead/Lag Pump Control
Build duplex pump control with alternation, failure detection, minimum run and off timers, and an operator override that survives a restart.
10 min readUpdated Aug 24, 2026
4-20 mA Signal Is Unstable
An analog reading that will not settle. How to separate a genuine process swing from induced noise, a ground loop, or a loop running out of voltage.
8 min readUpdated Aug 23, 2026
What Is a PLC?
A programmable logic controller is a ruggedized industrial computer that reads field inputs, solves a control program, and drives outputs on a repeating, deterministic cycle.
8 min readUpdated Aug 22, 2026
Modbus Device Intermittently Offline
A device that answers most of the time. Termination, bias, timing, and the physical layer details that produce a bus which almost works.
9 min readUpdated Aug 21, 2026
The Purdue Model
The reference architecture most segmentation designs still start from: what each level contains, where the DMZ goes, and how it maps to a water utility.
8 min readUpdated Aug 20, 2026
PID Control for Pumps and Valves
What each term actually does, how to tune a loop on a real pump station, and the handful of mistakes that cause most of the oscillation people blame on tuning.
11 min readUpdated Aug 19, 2026
Lead/Lag Pump Control
Which pump runs first, when the second joins, how they trade places, and the design decisions that determine whether a duplex station wears evenly.
9 min readUpdated Aug 18, 2026
Ethernet Device Drops Offline
An industrial Ethernet device that disappears and comes back. Duplex mismatch, cabling, spanning tree, and the switch counters that identify it in minutes.
9 min readUpdated Aug 16, 2026
ISA-18.2 Alarm Management
The lifecycle standard for alarm systems, the rate targets that define a workable system, and why alarm rationalization is the step nobody wants to fund.
10 min readUpdated Aug 15, 2026
How to Size a Control Panel Power Supply
Add up the real load, account for inrush and simultaneity, add headroom, and check the heat you just added to the enclosure.
7 min readUpdated Aug 14, 2026
How to Scale a 4-20 mA Input in a PLC
Turn raw analog counts into engineering units, verify at three points, and add the validity checks that stop a failed transmitter from producing a believable number.
7 min readUpdated Aug 12, 2026
Ladder Logic Fundamentals
Rungs, contacts, coils, and the relay conventions the language inherited — plus the patterns you will meet in almost every industrial program.
10 min readUpdated Aug 11, 2026
Ground Loops in Instrumentation
Two grounds at different potentials, one signal circuit between them, and a reading that will not sit still. How to find it and how to prevent it.
8 min readUpdated Aug 8, 2026
How to Test a 4-20 mA Loop
Prove a current loop end to end with a meter and a calibrator, without interrupting a process you were not authorized to interrupt.
8 min readUpdated Aug 6, 2026
What Is SCADA?
Supervisory control and data acquisition: the layer that collects data from controllers across a system, presents it to operators, records it, and lets them intervene.
9 min readUpdated Aug 4, 2026
Magnetic Flowmeters
Faraday's law applied to a pipe: how a mag meter works, the conductivity and full-pipe requirements, and why grounding decides whether it reads.
8 min readUpdated Aug 1, 2026
The PLC Scan Cycle
Read inputs, solve logic, write outputs, housekeeping. Understanding scan order explains most PLC behavior that looks wrong at first glance.
9 min readUpdated Jul 30, 2026
Modbus TCP
Modbus over Ethernet: what the MBAP header changes, why the CRC disappears, how the unit identifier works, and what does not get easier just because it is on Ethernet.
8 min readUpdated Jul 28, 2026
High Performance HMI Design
Grey backgrounds, reserved color, and displays designed to make abnormal conditions obvious rather than to look impressive in a demo.
8 min readUpdated Jul 24, 2026
Modbus RTU
Serial Modbus over RS-485: function codes, register addressing, the off-by-one that catches everyone, and the physical layer details that decide whether a bus is stable.
10 min readUpdated Jul 21, 2026
Analog Scaling: Raw Counts to Engineering Units
The arithmetic that turns an analog card reading into feet, psi, or gallons per minute — plus the range mismatches that silently corrupt it.
8 min readUpdated Jul 16, 2026
Radar Level Measurement
Non-contact and guided wave radar, why it handles a wet well better than most alternatives, and the installation details that decide whether it works.
9 min readUpdated Jul 9, 2026
Interlocks and Permissives
A permissive lets you start. An interlock stops you. Confusing the two produces equipment that either will not run or will not protect itself.
7 min readUpdated Jun 27, 2026
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Content on this site is general technical reference information. It is not engineering advice for a specific installation. Always follow the applicable codes, standards, manufacturer documentation, and your own site safety procedures. Verify against the equipment in front of you before you act.