Georg Fischer 2751 Specifications

Signet 2751 DryLoc® pH/ORP Smart Sensor
Electronics

Features

• Probe health monitoring, glass impedance and
broken glass detection

• Memory chip interface that allows for transferable
calibration, runtime data, and manufacturing
information

In-line

2751-1

DryLoc® Electrodes sold separately

The Signet 2751 pH/ORP Smart Sensor Electronics
featuring the DryLoc® connector, is the solution for field­free calibration, out of range glass impedance and broken
glass detection, alerting the operator to probe failure or
maintenance needs.

The 2751 features two different outputs: a two-wire
4 to 20 mA loop output with optional EasyCal function or a
digital (S
and is compatible with all Signet 8900, 9900 and 9950*
instruments or in blind, 4 to 20 mA.

The Smart Sensor Electronics will allow for calibration of
electrodes in a laboratory setting and installation of pre­calibrated probes in the field, reducing system downtime.
Memory chip enabled electrodes will store operational
data such as minimum and maximum pH/mV readings,
runtime, minimum and maximum temperature (pH only),
for troubleshooting and operational evaluation. To take full
advantage of all features and benefits of the 2751, use with
Signet 9900 (Generation IV or later), 9950 Transmitter or
0486 Profibus Concentrator.

The 2751 self-configures for pH or ORP operation via
automatic recognition of the electrode type. The optional
EasyCal feature allows simple push-button calibration and
includes an LED indicator for visual feedback.

The 2751 submersible Smart Sensor Electronic can also
be used in-line when used with the 3/4” or 1” threaded
sensors including the 272X, 273X, 275X, 276X and 277X
series of electrodes. The 2751 in-line sensor electronics
can be used with Signet fittings up to DN100 (4 in.) and
Wet-Tap assemblies.

3

L) output which allows for longer cable lengths

In-line EasyCal

2751-2

Submersible

2751-3 or 2751-4

• In-line integral mount and submersible

installation versions

• Automatic temperature compensation

• Auto confi guration for pH or ORP operation

• Optional EasyCal calibration aid with automatic
pH bu er recognition for 4, 7 and 10 pH and ORP
solutions: quinhydrone saturated pH 4 or 7 bu ers
and Light's Solution +469 mV

• Junction boxes for convenient wiring

• Patented DryLoc® connector provides a quick

and secure connection to the sensor**

Applications

• Water and Wastewater Treatment

• Neutralization Systems

• Scrubber Control

• E uent Monitoring

• Surface Finishing

• Flocculent Coagulation

• Heavy Metal Removal and Recovery

• Toxics Destruction

• Sanitization Systems

• Pool & Spa Control

• Aquatic Animal Life Support Systems

*Users of 9950 Gen I and 9950 (Gen 2a) should update to 9950 (Gen 2b,
available in Q4) to take full advantage of the 2751 features and benefits.
Visit www.gfsignet.com for the latest software update.

**U.S. Patent No.: 6,666,701

Specifi cations

General

Compatible Electrodes

Signet DryLoc® pH and ORP Electrodes, Models 2724-2726, 2734-2736, 2756-2757 Wet-Tap, 2764-2767, 2774-2777

Operating Range pH -1 to 15 pH

ORP ±2000 mV

Response Time pH < 6 sec. for 95% of change

ORP Application dependent

Materials In-line PBT (thermal plastic polyester) and polypropylene (retaining nut)

Submersible CPVC

Electrical

Cable 4.6 m 15 ft 3-conductor shielded (3-2751-1 in-line and the 3-2751-3 or -4 submersible

22 AWG For 9900, 9950 and 4 to 20 mA max. cable length is 300 m (1000 ft.).

Power 12 to 24 VDC ±10%, regulated for 4 to 20 mA output

5 to 6.5 VDC ±5% regulated recommended, 3 mA max., for digital (S

Current Output pH Fixed 4 to 20 mA, isolated, = 0 to 14 pH (custom scaling available with 0252 tool)

ORP Fixed 4 to 20 mA, isolated, = -1000 to +2000 mV (custom scaling available from

Max Loop Resistance 100  max. @ 12 V 325  max. @ 18 V 600  max. @ 24 V
Accuracy ±32 μA
Resolution ±5 μA
Update Rate 0.5 seconds
Error Indication 3.6 mA, 22 mA, or none
Digital (S

3

L) Output Serial ASCII, TTL level 9600 bps

Accuracy pH ± 0.02 pH @ 25 °C ± 0.02 pH @ 77 °F

ORP ± 1.5 mV @ 25 ° C ± 1.5 mV @ 77 °F
Temperature  0.4 °C 0.72 °F

Resolution pH  0.01 pH

ORP 1.5 mV
Update Rate 0.5 seconds
Available Data Raw mV, pH or ORP, Temperature (pH), Glass Impedance (pH), Minimum mV (pH), Maximum mV

(pH), Minimum Temperature (pH), Maximum Temperature (pH), Model Number, Serial Number,

Manufacturing Date, Runtime, Slope pH/mV, Measurement O set, and Temperature
Error Indication Open input diagnostic, broken glass detection (pH), High Impedance
Input Impedance, Z >10

11



Environmental

Enclosure 3-2751-1 & -2 NEMA 4X/IP65 with electrode connected

3-2751-3 & -4 NEMA 6P/IP68 with electrode and watertight conduit and/or extension

Max. Temperature/Pressure Rating

Operating Temperature

Submersible 0 °C to 85 °C 32 °F to 185 °F
In-line 0 °C to 85 °C 32 °F to 185 °F

Storage Temperature -20 °C to 85 °C -4 °F to 185 °F
Relative Humidity 0 to 95%, non-condensing (without electrode connected)

Shipping Weight

2751-2 0.75 kg 1.65 lb

2751-1, -3 & -4 0.64 kg 1.41 lb

Standards and Approvals

CE, FCC

RoHS compliant, China RoHS

Manufactured under ISO 9001 for Quality and ISO 14001 for Environmental Management and

OHSAS 18001 for Occupational Health and Safety

sensor electronics only)

For 8900, please refer to the Cable Calculation Table of the Signet catalog for
max. cable length.

3

L) output

± 2000 mV with 0252 tool)

pipe connected

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