GF pH Probe (For NDS, NDK)

In-Line DryLoc pH Sensor for the Growlink Nutrient Doser The 2751-2 is the in-line variant of the Signet 2751 family. It auto-recognizes whether the connected electrode is a pH or ORP probe and self-configures the signal chain on power-up. A field-free calibration routine lets you set zero and slope without a buffer when one isn't on hand. Out-of-range glass impedance and broken-glass detection raise an alert the moment a probe drifts past its serviceable life. That matters when a worn pH electrode is masking off-recipe feeds. pH/ORP Smart Sensor Electronics with EasyCal and DryLoc Connection The 4-20 mA two-wire loop output runs back to a Growlink Nutrient Doser, Connect Controller, or any standard PLC. Built-in preamplification keeps signal integrity intact for cable runs up to 1,000 feet. EasyCal handles routine recalibration with a single button press and an LED indicator. Drop the probe in pH 7 buffer, press, watch the LED. The DryLoc connector pulls apart for storage or hot-swap without exposing the contacts to feed water. The integral NEMA 4X junction enclosure keeps the wiring side sealed against wash-down and humid air. Key Features DryLoc connector for in-line installation: Dry-contact electrode coupling — pull apart for service without dousing the wiring side. pH 0-14 / ORP ±2,000 mV operating range: Auto-recognizes the electrode and self-configures, so one head covers both measurements. Broken-glass and out-of-range impedance detection: Alarms when a pH bulb is cracked or the membrane has aged past usable life. EasyCal one-button calibration: Field-free recalibration with an LED visual indicator — no buffer juggling, no menu trees. 4-20 mA two-wire loop + S3L digital option: Loop output for any PLC; digital S3L available in the family for longer runs. Built-in preamplification, 1,000 ft cable run: Keeps signal integrity over distribution-room distances. NEMA 4X integral junction enclosure: Sealed against grow-room humidity and wash-down on the wiring side. Technical Specifications Specification Value Model GF Signet 3-2751-2 (In-line, 4-20 mA) Measurement pH and ORP (auto-recognized via electrode) pH range 0 to 14 pH (family rated -1 to 15) ORP range ±2,000 mV pH response time <6 sec for 95% of change Output 4-20 mA, two-wire loop with EasyCal Alternate outputs (family) S3L digital available on -1 and -4 variants Electrode connector DryLoc Operating temperature 32°F to 185°F (storage -4°F to 185°F) Cable 4.6 m (15 ft), 3-conductor shielded, 22 AWG Cable run with preamp Up to 305 m (1,000 ft) Power supply 12-24 VDC ±10% (4-20 mA); 5-6.5 VDC ±5% (S3L) Enclosure NEMA 4X (integral, in-line version) Body material PBT polyester Diagnostics Broken-glass alert, out-of-range glass impedance Calibration EasyCal one-button with LED indicator Compatibility Growlink Nutrient Doser System (NDS), Nutrient Doser Kit (NDK); GF 8900/9900/9950 instruments; generic 4-20 mA PLC