Georg Fischer 2751 Operating Manual

Signet 2751 DryLoc® pH/ORP Smart Sensor Electronics

*3-2751.090*

3-2751.090 Rev. B 08/17

Operating Instructions

Description

Signet 3-2751 pH/ORP Smart Sensor Electronics is a blind transmitter that processes
analog signals from a pH or ORP electrode and transmits digital data via a three wire

2751-1

cable to a 9900 or 9950 Signet transmitter or a Signet 0486 Profi bus Concentrator. The
serial bus, Signet Serial Sensor Link (S
technology from Signet.

The Signet 2751 can also output the signal over a 4 to 20 mA current loop with a
pre-set scale without the expense of local display. Preamplifi cation is built-in reducing
system costs while ensuring absolute signal integrity up to 305 m (1,000 ft).

The Smart Sensor Electronics self-confi gure for pH or ORP via automatic recognition
of electrode type. The DryLoc electrode connector quickly forms a robust assembly
with the sensor for submersible and in-line installations. The Smart Sensor Electronics
offers broken glass and high impedance detection, remote calibration, storage of
environmental extremes, and manufacturing electrode data. (see page 10 for details).

NEMA 4X Junction Boxes are integral parts of the in-line version and are available as
accessories for the submersible version.

The optional EasyCal feature allows simple push-button calibration and includes an
LED for visual feedback.

3

L) is the latest development in leading-edge

English

2751-2

2751-3, 2751-4

• English

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Table of Contents

Warranty Information ...............................................................................2

Product Registration ................................................................................2

Safety Information ...................................................................................2

Chemical Compatibility ............................................................................2

Specifi cations ..........................................................................................3

In-line Installation.....................................................................................4

Mounting Position ....................................................................................5

In-line Assembly ......................................................................................5

Submersible Installation ..........................................................................7

Digital (S3L) Wiring ..................................................................................8

4 to 20 mA Loop Wiring ...........................................................................8

Calibration ...............................................................................................9

2751 Advanced Features.......................................................................10

Troubleshooting .....................................................................................10

Parts and Accessories ........................................................................... 11

Ordering Information..............................................................................12

Warranty Information

Safety Information

Refer to your local Georg Fischer Sales offi ce for the most
current warranty statement.

All warranty and non-warranty repairs being returned must
include a fully completed Service Form and goods must be
returned to your local GF Sales offi ce or distributor.
Product returned without a Service Form may not be
warranty replaced or repaired.

Signet products with limited shelf-life (e.g. pH, ORP, chlorine
electrodes, calibration solutions; e.g. pH buffers, turbidity
standards or other solutions) are warranted out of box but not
warranted against any damage, due to process or application
failures (e.g. high temperature, chemical poisoning, dry-out) or
mishandling (e.g. broken glass, damaged membrane, freezing
and/or extreme temperatures).

Product Registration

Thank you for purchasing the Signet line of Georg Fischer
measurement products.

If you would like to register your product(s), you can now register
online in one of the following ways:

• Visit our website www.gfsignet.com. Under Service and
Support click on Product Registration Form

• If this is a pdf manual (digital copy),

click here

1. Depressurize and vent system prior to installation or removal.

2. Confi rm chemical compatibility before use.

3. Do not exceed maximum temperature/pressure specifi cations.

4. Wear safety goggles or faceshield during installation/service.

5. Do not alter product construction.

6. When using chemicals or solvents care should be taken
and appropriate eye, face, hand, body, and/or respiratory
protection should be used.

Caution / Warning / Danger

Indicates a potential hazard. Failure to follow all warnings
may lead to equipment damage, injury, or death

Personal Protective Equipment (PPE)

Always utilize the most appropriate PPE during
installation and service of Signet products.

Pressurized System Warning

Sensor may be under pressure, take caution to vent
system prior to installation or removal. Failure to do so
may result in equipment damage and/or serious injury.

Hand Tighten Only

Overtightening may permanently damage product threads
and lead to failure of the retaining nut.

Do Not Use Tools

Use of tool(s) may damage product beyond repair and
potentially void product warranty.

Note / Technical Notes

Highlights additional information or detailed procedure.

Chemical Compatibility

The retaining nuts of pH and ORP sensors are not designed
for prolonged contact with aggressive substances.

Strong acids, caustic substances and solvents
or their vapor may lead to failure of the retaining
nut, ejection of the sensor and loss of the process
fl uid with possibly serious consequences, such as
damage to equipment and serious personal injury.

Retaining nuts that may have been in contact with
such substances e.g. due to leakage or spilling,
must be replaced.

2

2751 DryLoc pH/ORP Smart Sensor Electronics

Specifi cations

General

Compatible Electrodes ............... Signet DryLoc Electrodes

(PT1000 or 3K Balco
temperature sensor
versions for pH)

Operational Range ..................... -1.00 to 15.00 pH,

-2000 to +2000 mV ORP,
0 °C to 85 °C (32 °F to 185 °F)

Response Time (includes electrode response):

pH ........................................... <6 s for 95% of change

ORP ........................................application dependent

pH Temp T90 ......................... 200 s (2724 and 2734)

132 s (2726 and 2736)
438 s (2756-WT)

Materials

2751-1, 2751-2 (in-line) ............... PBT (thermal plastic polyester),

PP (retaining nut)

2751 -3, -4 (submersible) ............ CPVC

Cable for 2751 -3, -4 submersible versions:

4.6 m (15 ft) 3-conductor shielded, 22 AWG

• May be extended up to 305 m (1000 ft) with current output

• May be extended up to 305 m (1000 ft) with (S3L) output
Weight:

2751-2 (in-line)..... ....................... 0.75 kg

2751-1 (in-line) &

2751 -3, -4 (submersible).... ........ 0.64 kg

Environmental

Ambient Temp. ...........................0 °C to 85 °C (32 °F to 185 °F)

Storage Temp. ........................... -20 °C to 85 °C (-4 °F to 185 °F)

Relative Humidity ....................... 95% max, non-condensing

Immunity .....................................EN50082-2

Emissions ...................................EN50081-1

Enclosure Rating

2751 -1, 2751 -2 (in-line) .......... NEMA 4X/IP65

(with electrode connected)

2751 -3, 2751 -4 (submersible) NEMA 6P/IP68

(with electrode and watertight
extension pipe connected)

Electrical

Input Impedance ........................>10

11



Input response time ...................500 ms

Temperature drift........................ ±0.002 pH per ºC,

±0.1 mV ORP per ºC

Input resolution ...........................0.02 pH, 1 mV ORP, 0.3 ºC

Current output

pH .............................................. Fixed 4 to 20 mA, isolated,

0 to 14 pH
(custom scaling available)

ORP ............................................ Fixed 4 to 20 mA, isolated,

–1000 to +2000 mV
(custom scaling available,

–2000 to +2000 mV)

Power ......................................... 12-24 VDC ± 10% regulated

for 4 to 20 mA output

Max Loop Resistance ................100  max. @ 12V

400  max. @ 18V
700  max. @ 24V

Loop Accuracy............................±32 A @ 25 ºC

Temperature drift........................±1 A per ºC

Output resolution ........................± 5 A

Error indication ...........................3.6 mA, 22 mA or none

Update Rate.............. .................0.5 seconds

3

Digital (S

L) output:

Description ................................. Serial ASCII,

TTL level 9600 bps

Power ......................................... 5 to 6.5 VDC ± 5% regulated

supply, 2.5 mA max

Update Rate.............. .................0.5 seconds

Available Data...... ......................Raw mV, pH or ORP, Glass

Impedance (pH), Minimum and Maximum pH, Minimum
and Maximum mV (ORP), Minimum Temperature (pH),
Maximum Temperature (pH), Model Number, Serial Number,
Manufacturing Date, Runtime, Slope pH/mV, Measurement
Offset, and Temperature Offset (pH)

System Accuracy:

pH ........................................... ± 0.02 pH @ 25 °C

ORP ........................................ ± 1.5 mV @ 25 °C

Temperature ..... .....................0.4 °C

Resolution:

pH ........................................... 0.01 pH

ORP ........................................1.5 mV

Temperature. ..........................0.1 °C

Error indication ...........................Temp output "+999.9"

Standards and Approvals

• CE, RoHS Compliant

• Manufactured under ISO 9001 for Quality,

ISO 14001 for Environmental Management and

OHSAS 18001 for Occupational Health and Safety.
China RoHS (Go to www.gfsignet.com for details)

Declaration of Conformity according to FCC Part 15.

This device complies with Part 15 of the FCC rules.

Operation is subject to the following two conditions:

(1) This device may not cause harmful interference, and,

(2) This device must accept any interference received,

including interference that may cause undesired operation.

2751 DryLoc pH/ORP Smart Sensor Electronics

3

In-Line Dimensions

1. 2751-1 In-Line sensor (without EasyCal) is designed for applications where electrode calibration is facilitated by remote equipment.

• A Signet installation fi tting (12.7 mm to 101.6 mm [1/2 in. to 4 in.]), Wet-Tap assembly or a threaded tee is required to secure the
electrode in the pipe.

2. 2751-2 In-Line sensor includes EasyCal.

• 272X, 273X, 276X and 277X series of sensors thread directly into standard 1 in or ¾ in NPT fi ttings.

• The Signet Measurement and Instrumentation catalog offers a complete selection of fi ttings.

• 272x and 273x series of pH and ORP electrodes are compatible with Signet Installation Fittings.

3. The 2751-3 and 2751-4 submersible sensor electronics are recommended for in-line applications using the 272X, 273X, 276X and the
277x series threaded DryLoc sensors.

4. 2756 and 2757 Wet-Tap sensors require the 3719 Wet-Tap assembly and can use the 2751-1 or 2751-2 versions.

1 2

94 mm

(3.7 in.)

*

**

140 mm
117 mm
(4.6 in.)

2751-1 and 2751-2 with 272X, 273X, 276X OR 277X sensors

(5.5 in.)

3 4

56.6 mm
(2.23 in.)

*

102 mm

(4.02 in.)

**

229 mm

(9.0 in.)

83 mm
(3.27 in)

11 4 mm
(4.5 in)

*

190.6 mm
(7.5 in.)

2751-3 and 2751-4 with 272X, 273X, 2764 or 2774 sensors

* NOTE:

Lightly lubricate O-rings with a non-petroleum based, viscous lubricant
(grease) compatible with the system.

4

2751 DryLoc pH/ORP Smart Sensor Electronics

248 mm
(9.75 in)

*

2751-1 and 2751-2 with

3719 Wet Tap and 2756 or 2757 Sensors

*

45 mm
(1.75 in)