HM Digital PSC-154 TDS/EC Controller – 4-20mA Output, Commercial Grade

HM Digital PSC-154 TDS/EC Controller – Commercial-Grade Water Quality Control with 4-20mA Output The HM Digital PSC-154 is a professional-grade inline TDS/EC controller engineered for high-output commercial and industrial water treatment systems. It continuously monitors total dissolved solids (TDS) and electrical conductivity (EC), triggers an audible alarm when levels exceed your set point, and outputs a 4-20mA signal for direct integration with PLCs and data logging systems — all displayed on a large, bright tri-color LED screen with on-screen temperature readout. Designed for demanding applications including commercial RO systems, hydroponics, aquaculture, water purification facilities, and industrial process water monitoring. Key Features 4-20mA analog output — industry-standard signal connects directly to PLCs, SCADA systems, and data loggers for continuous remote monitoring and automated control Audible alarm — sounds when TDS/EC rises above the user-configured set point, enabling immediate response to water quality exceedances Relay switch control — activates or deactivates a connected device (pump, valve, solenoid) based on the programmed set point for fully automated water quality management Tri-color LED display — large, bright display changes color based on water quality status for at-a-glance monitoring across the room On-screen temperature display — shows real-time temperature in °C or °F alongside TDS/EC readings for comprehensive water quality data in a single view Digital calibration — precise on-unit calibration without external tools Extended measurement range — designed for high-output commercial systems with broader TDS/EC range than standard inline controllers Includes sensor probe — ships with one SP-1-PSC sensor probe ready for immediate installation How It Works The PSC-154 installs inline in your water line via the included SP-1-PSC sensor probe. As water flows past the probe, the controller continuously measures TDS (in ppm) and EC (in μS/cm) and displays readings on the tri-color LED panel. When readings exceed your programmed set point, the unit simultaneously triggers the audible alarm, changes display color, and activates the relay output to control a connected device. The 4-20mA output runs continuously to your PLC or data logger for uninterrupted process monitoring and record-keeping. Ideal Applications Commercial reverse osmosis (RO) systems — monitor permeate TDS and trigger alerts or shutoffs when membrane performance degrades Hydroponics & aquaponics — maintain precise nutrient solution EC levels with automated control Aquaculture — continuous water quality monitoring for fish and shellfish production Water purification facilities — process water quality control with PLC integration Industrial process water — boiler feed water, cooling tower makeup, and rinse water monitoring Laboratory & research — precise TDS/EC measurement with data logging capability 4-20mA Output: Why It Matters The 4-20mA current loop is the global standard for industrial process instrumentation. Unlike voltage signals, current loop signals are immune to line resistance and electrical noise over long cable runs — making them reliable in electrically noisy industrial environments. The PSC-154’s 4-20mA output connects directly to any PLC, DCS, SCADA system, or data acquisition device that accepts standard analog input, enabling seamless integration into existing automation infrastructure without signal converters or additional hardware. Product Specifications SKU: PSC-154 | UPC: 891144000366 Measurement parameters: TDS (ppm) and EC (μS/cm) Output: 4-20mA analog current loop Display: Large tri-color LED (status-color-coded) Temperature display: °C / °F selectable Calibration: Digital, on-unit Alarm: Audible, user-configurable set point Relay: Device control switch based on set point Included: SP-1-PSC sensor probe Weight: 1.5 lbs Vendor: HM Digital Country of origin: South Korea Frequently Asked Questions What does the HM Digital PSC-154 measure? The PSC-154 measures total dissolved solids (TDS) in parts per million (ppm) and electrical conductivity (EC) in microsiemens per centimeter (μS/cm). It also displays real-time water temperature in °C or °F on the same screen. What is the 4-20mA output used for? The 4-20mA analog output connects the PSC-154 to PLCs, SCADA systems, DCS platforms, and data loggers for continuous remote monitoring and automated process control. The 4-20mA current loop is the global standard for industrial instrumentation and is immune to electrical noise over long cable runs, making it reliable in industrial environments. Can the PSC-154 control a pump or valve automatically? Yes. The PSC-154 includes a relay switch that activates or deactivates a connected device — such as a pump, solenoid valve, or dosing system — based on the user-programmed TDS/EC set point. This enables fully automated water quality management without manual intervention. What sensor probe does the PSC-154 use? The PSC-154 ships with one SP-1-PSC sensor probe included. The probe installs inline in your water line and continuously feeds TDS/EC readings to the controller. What is the difference between the PSC-154 and a standard inline TDS meter? A standard inline TDS meter displays readings only. The PSC-154 adds: a user-configurable alarm set point, a relay switch for automated device control, a 4-20mA output for PLC/data logger integration, a tri-color status display, and on-screen temperature readout. It is a full process controller, not just a monitor. What applications is the PSC-154 designed for? The PSC-154 is designed for high-output commercial and industrial applications including commercial RO systems, hydroponics, aquaponics, aquaculture, water purification facilities, industrial process water monitoring, and laboratory research requiring continuous TDS/EC measurement with data logging. Where is the HM Digital PSC-154 made? The PSC-154 is manufactured in South Korea by HM Digital, a specialist in water quality measurement instrumentation.