https://www.currycontrols.com/ An independent controls and automation knowledge hub covering PLCs, SCADA, instrumentation, control panels, industrial networking, OT cybersecurity, and water and wastewater control systems. en-us Sat, 05 Sep 2026 10:02:16 GMT 1440 https://www.currycontrols.com/water-wastewater/wastewater-systems/lift-stations/wet-well-control https://www.currycontrols.com/water-wastewater/wastewater-systems/lift-stations/wet-well-control The measurement that runs a lift station: choosing setpoints, protecting the pumps, validating the signal, and the failures that flood a station. Reference Sun, 30 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/analog-control/4-20-ma https://www.currycontrols.com/controls/plc-systems/analog-control/4-20-ma 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. Reference Sat, 29 Aug 2026 00:00:00 GMT https://www.currycontrols.com/cybersecurity/water-wastewater-cybersecurity/utility-threat-landscape https://www.currycontrols.com/cybersecurity/water-wastewater-cybersecurity/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. Reference Fri, 28 Aug 2026 00:00:00 GMT https://www.currycontrols.com/water-wastewater/wastewater-systems/lift-stations/duplex-lift-stations https://www.currycontrols.com/water-wastewater/wastewater-systems/lift-stations/duplex-lift-stations 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. Reference Thu, 27 Aug 2026 00:00:00 GMT https://www.currycontrols.com/cybersecurity/ot-security/ot-vs-it-security https://www.currycontrols.com/cybersecurity/ot-security/ot-vs-it-security Why the familiar security priorities invert on a plant floor, and what that changes about patching, scanning, authentication, and incident response. Reference Wed, 26 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/control-panels/panel-design/ul-508a https://www.currycontrols.com/controls/control-panels/panel-design/ul-508a What the listing actually covers, what has to appear on the label, and the requirements that most often cause a panel to fail inspection. Reference Tue, 25 Aug 2026 00:00:00 GMT https://www.currycontrols.com/how-to/plc-how-to/program-lead-lag-pumps https://www.currycontrols.com/how-to/plc-how-to/program-lead-lag-pumps Build duplex pump control with alternation, failure detection, minimum run and off timers, and an operator override that survives a restart. How-To Mon, 24 Aug 2026 00:00:00 GMT https://www.currycontrols.com/troubleshooting/instrumentation-troubleshooting/4-20-ma-signal-unstable https://www.currycontrols.com/troubleshooting/instrumentation-troubleshooting/4-20-ma-signal-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. Troubleshooting Sun, 23 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/plc-fundamentals/what-is-a-plc https://www.currycontrols.com/controls/plc-systems/plc-fundamentals/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. Reference Sat, 22 Aug 2026 00:00:00 GMT https://www.currycontrols.com/troubleshooting/communications-troubleshooting/modbus-device-intermittently-offline https://www.currycontrols.com/troubleshooting/communications-troubleshooting/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. Troubleshooting Fri, 21 Aug 2026 00:00:00 GMT https://www.currycontrols.com/cybersecurity/ot-security/purdue-model https://www.currycontrols.com/cybersecurity/ot-security/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. Reference Thu, 20 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/analog-control/pid https://www.currycontrols.com/controls/plc-systems/analog-control/pid 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. Reference Wed, 19 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/control-panels/pump-panels/lead-lag https://www.currycontrols.com/controls/control-panels/pump-panels/lead-lag Which pump runs first, when the second joins, how they trade places, and the design decisions that determine whether a duplex station wears evenly. Reference Tue, 18 Aug 2026 00:00:00 GMT https://www.currycontrols.com/troubleshooting/network-troubleshooting/ethernet-device-drops-offline https://www.currycontrols.com/troubleshooting/network-troubleshooting/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. Troubleshooting Sun, 16 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/scada-hmi/alarm-management/isa-18-2 https://www.currycontrols.com/controls/scada-hmi/alarm-management/isa-18-2 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. Reference Sat, 15 Aug 2026 00:00:00 GMT https://www.currycontrols.com/how-to/panel-how-to/size-a-power-supply https://www.currycontrols.com/how-to/panel-how-to/size-a-power-supply Add up the real load, account for inrush and simultaneity, add headroom, and check the heat you just added to the enclosure. How-To Fri, 14 Aug 2026 00:00:00 GMT https://www.currycontrols.com/how-to/plc-how-to/scale-a-4-20-ma-input https://www.currycontrols.com/how-to/plc-how-to/scale-a-4-20-ma-input 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. How-To Wed, 12 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/programming/ladder-logic https://www.currycontrols.com/controls/plc-systems/programming/ladder-logic Rungs, contacts, coils, and the relay conventions the language inherited — plus the patterns you will meet in almost every industrial program. Reference Tue, 11 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/instrumentation/signals/ground-loops https://www.currycontrols.com/controls/instrumentation/signals/ground-loops 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. Reference Sat, 08 Aug 2026 00:00:00 GMT https://www.currycontrols.com/how-to/instrumentation-how-to/test-a-4-20-ma-loop https://www.currycontrols.com/how-to/instrumentation-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. How-To Thu, 06 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/scada-hmi/scada-fundamentals/what-is-scada https://www.currycontrols.com/controls/scada-hmi/scada-fundamentals/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. Reference Tue, 04 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/instrumentation/flow/magnetic-flowmeters https://www.currycontrols.com/controls/instrumentation/flow/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. Reference Sat, 01 Aug 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/plc-fundamentals/scan-cycle https://www.currycontrols.com/controls/plc-systems/plc-fundamentals/scan-cycle Read inputs, solve logic, write outputs, housekeeping. Understanding scan order explains most PLC behavior that looks wrong at first glance. Reference Thu, 30 Jul 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/communications/modbus-tcp https://www.currycontrols.com/controls/plc-systems/communications/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. Reference Tue, 28 Jul 2026 00:00:00 GMT https://www.currycontrols.com/controls/scada-hmi/hmi-design/high-performance-hmi https://www.currycontrols.com/controls/scada-hmi/hmi-design/high-performance-hmi Grey backgrounds, reserved color, and displays designed to make abnormal conditions obvious rather than to look impressive in a demo. Reference Fri, 24 Jul 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/communications/modbus-rtu https://www.currycontrols.com/controls/plc-systems/communications/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. Reference Tue, 21 Jul 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/analog-control/scaling https://www.currycontrols.com/controls/plc-systems/analog-control/scaling The arithmetic that turns an analog card reading into feet, psi, or gallons per minute — plus the range mismatches that silently corrupt it. Reference Thu, 16 Jul 2026 00:00:00 GMT https://www.currycontrols.com/controls/instrumentation/level/radar-level https://www.currycontrols.com/controls/instrumentation/level/radar-level 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. Reference Thu, 09 Jul 2026 00:00:00 GMT https://www.currycontrols.com/controls/plc-systems/programming/interlocks https://www.currycontrols.com/controls/plc-systems/programming/interlocks A permissive lets you start. An interlock stops you. Confusing the two produces equipment that either will not run or will not protect itself. Reference Sat, 27 Jun 2026 00:00:00 GMT