The HM Digital PSC-150 is a panel-mount controller that continuously monitors Total Dissolved Solids (TDS) or Electrical Conductivity (EC) and acts on it. When the reading reaches the user-set point it lights a warning, sounds an optional alarm and switches an isolated dry contact to start or stop a pump, solenoid valve or other device.
The PSC-150 is mechanically and functionally identical to the PSC-154 but has no 4–20 mA output. Choose the PSC-154 if the reading has to reach a PLC, SCADA system or chart recorder; choose the PSC-150 for standalone set-point control. Supplied with sensor, 3 m shielded cable, power cord, mounting brackets and U.S. plug adapter.
| SKU / Model | PSC-150 |
| Product Type | Panel-mount TDS / EC controller (no analogue output) |
| EC Range | 0–9999 µS (µS/cm) |
| TDS Range | 0–9999 ppm (mg/L) |
| Temperature Range | 1–80 °C (33–176 °F) |
| Resolution | 0–999: 0.1 µS/ppm · 1000–9999: 1 µS/ppm · 0.1 °C/°F |
| Accuracy | ±2% of reading · Thermometer ±0.5 °C |
| Temperature Compensation | Automatic (ATC), 1–80 °C |
| Calibration | Digital push-button, with manual trimmer-pot fine-tuning in high ranges |
| Set Point | Single point, set by on-screen UP/DOWN buttons to any value in range |
| Set-Point Relay | Single, isolated dry contact — 2 A, max 220 V, resistive load, 100,000 strokes |
| Relay Voltage | 5 V (the connected device requires its own power source) |
| Analog Output | None — see the PSC-154 for 4–20 mA output |
| Alarm | Optional steady beep, user-selectable |
| Probe / Sensor | ½" NPTF bushing — sensor model SP-1-PSC |
| Cable Length | 3 m (9.8 ft) shielded |
| Display | Bright tri-colour LED — simultaneous EC/TDS and temperature |
| Power Supply | 110 V / 220 V, ±10% Vac, 50/60 Hz |
| Enclosure | ABS, front and back |
| Operating Environment | 0–50 °C (32–122 °F); RH max 80% non-condensing |
| Panel Cut-Out | 67 × 67 mm (2-21/32" × 2-21/32") |
| Dimensions | 7.2 × 7.2 × 11.1 cm (2.8 × 2.8 × 4.4 in) |
| Weight | 241 g (8.5 oz) |
| Factory Calibration | 1413 µS NaCl solution (700 ppm) |
| Warranty | 1 Year Limited Warranty — controller and sensor |
Specifications transcribed from HM Digital User’s Guide Ver 2.2E (document 200828), the current revision supplied with the unit.
📖 User’s Guide Ver 2.2E (PDF)The guide covers both the PSC-150 and the PSC-154 — installation, calibration, set-point programming, wiring and troubleshooting. Published by HM Digital, Inc.
