ENGLISH 3-2750.090 B-8/01 English SAFETY INSTRUCTIONS FOR IN-LINE ELECTRODE INSTALLATION 1. Do not remove from pressurized lines. 2. Do not exceed maximum temperature/pressure specifications. 3. Wear safety goggles or face shield during installation/service. 4. Do not alter product construction. Failure to follow safety instructions may result in severe personal injury! Description: +GF+ SIGNET 2750 ph/orp Sensors offer two output options: If provided with 12-24 VDC power, the 2750 will output a two-wire 4 to 20mA loop. If provided with 5 VDC power, the 2750 will output digital serial data (the format is S 3 L : Signet Sensor Serial Link, a proprietary digital output for use with +GF+ SIGNET equipment). The 2750 automatically recognizes +GF+ SIGNET 275X ph or ORP electrodes and scales the current output for the appropriate range. The range is factory set for full scale measurement: 4 to20 ma = 0 to 14 ph 4 to20 ma = -1000 to +2000 mv ORP. Custom scaling is available from the factory. Three versions are available to accommodate different application requirements: 2750-1 In-line installations 2750-2 In-line installations with Local EasyCal 2750-3 Submersible installations, 3/4 in. NPT threads 2750-4 Submersible installations, ISO 7-1/R 3/4 threads Technical Data General Compatible Electrodes: +GF+ SIGNET 275X ph/orp Electrodes Temperature sensor: PT1000 Operational Range: ph: 0.00 to 14.00 ORP: ±2000 mv Temp. 0 C to 85 C (32ºF to 185ºF) Response Time (includes electrode response): ph: <6 s for 95% of change ORP: application dependent Temp τ: 140 seconds (2754), 196 seconds (2756) Materials: 2750-1&2 (in-line): PBT (thermal plastic polyester) 2750-3 (submersible): CPVC Weight: 2750-1&2 (in-line): 0.75 kg (1.75 lb.) 2750-3 (submersible): 0.64 kg (1.4 lb.) Electrical Input Impedance: >10 11 Ω Output update rate: 0.5 s Current output: Power: 12 to 24 VDC ± 10% regulated, 20 ma max. ph scale: Fixed 4 to 20 ma, isolated, 0.00 to 14.00 (custom scaling available) ORP scale: Fixed 4 to 20 ma, isolated, -1000 to 2000 mv (custom scaling available, -2000 to 2000 mv) Max Loop Resistance: 50Ω max. @ 12V 325Ω max. @ 18V 600Ω max. @ 24V Accuracy: ±32µA @ 25ºC Temperature drift: ±1µA per ºC Resolution: ± 5µA Error indication: 3.6 ma S3L output: Description: Serial ASCII, TTL level 9600 bps Power: 5VDC ±5% regulated, 3 ma max Accuracy: ph: ± 0.03 ph @ 25 C ORP: ± 2 mv @ 25 C Resolution: ph: 0.02 ph ORP: 1 mv Temp. 0.2 C Error indication: Temp output "+999.9" Environmental Ambient Temp.: -10 C to 85 C Storage Temp.: -20 C to 85 C Immunity: EN50082-2 Emissions: EN50081-1 Enclosure Rating: 2750-1&2 (in-line): NEMA 4X/IP65 (with electrode connected) 2750-3 (submersible): NEMA 6P/IP68 (with electrode and watertight extension pipe connected) Standards and Approvals CE Manufactured under ISO 9001 & ISO 14001 page 1 of 8
Technical Data General Compatibility: +GF+ SIGNET 2750 ph/orp sensor Pressure/Temperature rating (ph and ORP electrodes) Pipe Size Range: 1/2 and up. Use +GF+ SIGNET installation fittings to 4 in. Use pipe adapters in pipes over 4 in. Submersion with 2750 sensor requires 3/4 in. NPT or ISO 7-1/R 3/4 male threaded extensions Efficiency: >97% @ 25 C (77 F) Response Time: ph: < 5 s for 95% of signal change ORP: Application dependent BAR 7 5 3 PSI 100 75 50 2754 Primary Functions: 2754, 2755: Flat surface resists fouling 2756, 2757: Bulb surface for general use 2754-HF: Extended use in applications with trace hydrofluoric acid (<2%) 2756-DI: Extended use in pure waters (<100 µs) 2 25 0 10 32 50 25 77 50 122 75 167 C F 2754 and 2756 ph Electrodes Operating Range: 0 to 14 ph Wetted Materials: CPVC Body Glass FPM O-rings Porous UHMW Polyethylene reference junctions ph Reference: Electrolyte: Solidified Acrylamide Gel 3.5M KCI (2754, 2754-HF, 2756) 0.1 M KCl (2756-DI) Element: Ag/AgCl Temperature Sensor: PT-1000 (1096.8Ω = 25 C) Response Time, τ: 140 secs. (2754), 196 secs. (2756) 1.3 2755/2757 ORP Electrodes Operating Range: -2000 to +2000 mv Wetted Materials: CPVC Body Glass FPM 0-rings Porous UHMW Polyethylene reference junctions Platinum sensing surface ORP Reference: Solidified Acrlyamide Gel:3.5M KCL saturated with AgCl Element: Ag/AgCl Temperature and pressure specifications ORP electrode operating Temperature/Pressure 6.89 bar @ 0 C to 65ºC (100 psi @ 32 to 149 F) 4.00 bar @ 66ºC to 85 C (58 psi @150 to 185 F) 2756 and 2756-DI ph electrode operating Temperature/Pressure 6.89 bar @ 0 C to 65ºC (100 psi @ 32 to 149 F) 4.00 bar @ 66ºC to 85 C (58 psi @150 to 185 F) 2754 and 2754-HF ph electrode operating Temperature/Pressure 6.89 bar @ 10 C to 65ºC (100 psi @ 50 to 149 F) 4.00 bar @ 66ºC to 85 C (58 psi @150 to 185 F) Storage Temperature: > -12 C (11 F) Cable supplied: 15 ft. 3 conductor shielded, 22 AWG. May be extended up to 122 m (400 ft) Submersible installation 3-2754 Flat ph 3-2755 Flat ORP 1.06 in./ 27 mm 3-2756 Bulb ph 3-2757 Bulb ORP 1.06 in./ 27 mm In-Line installation 3.7 in./ 94 mm 1.4 in./ 35.3 mm 4.3 in./ 109 mm 1.4 in./ 35.3 mm 4.6 in./ 116 mm 7.1 in./ 181 mm 8.2 in./ 208 mm 2.9 in./ 74 mm 3.2 in./ 81 mm 0.72 in./ 18 mm 0.72 in./ 18 mm 2.16 in./ 55 mm page 2 of 8
2750 In-line ph Sensor Installation The 2750-1 in-line sensor (without Local EasyCal) is designed for applications where electrode calibration is facilitated by remote equipment. The 2750-2 In-Line sensor includes Local EasyCal. A +GF+ SIGNET installation fitting (1/2 in. to 4 in.) or a +GF+ SIGNET pipe adapter is required to secure the electrode in the pipe. The +GF+ SIGNET Measurement and Instrumentation catalog offers a complete selection of fittings. Type Description Type Description Plastic tees Available in 1/2 in. to 4 in. sizes PVC, CPVC w/solvent cement socket PVDF and PP w/union end fittings Carbon steel weldolets Available in 2 in. to 4 in. sizes Requires 1-7/16 in. hole in pipe Install by certified welder only PVC saddles Available in 2 in. to 4 in. sizes Requires 1-7/16 in. hole in pipe Carbon steel threaded tees Available in 1/2 in. to 2 in. sizes Female NPT ends Iron strap-on saddles Available in 2 in. to 4 in. sizes Requires 1-7/16 in. hole in pipe Universal pipe adapters Adapt any fitting with 1-1/4 in. outlet PVC, CPVC, or PVDF versions Specify socket or 1-1/4 inch NPT male threads 8052-1 NPT Junction box 4.2 in. 107 mm YES YES 3.7 in./ 94 mm 30º 8050-1 Universal Junction box 4.2 in./ 106 mm NO NO 3.7 in./ 94 mm NO Vertical (0 ) position optimum Do not install within 30º of horizontal page 3 of 8
2750 In-line ph Sensor Assembly 1. Insert electrode into Signet installation fitting. Seat the electrode tabs into the alignment notches in the fitting. 2. Thread the in-line retaining cap onto fitting to secure the electrode into place. Hand-tighten the cap. DO NOT use any tools to avoid damaging the threads. Note: Keep the electrical interconnection between electrode and sensor electronics dry and clean at all times. 3. Disengage the locking ring on base of 2750 (The ring is disengaged when the lines on the ring and body of the 2750 are not aligned.) Unlocked 4. Place 2750 onto top of electrode and turn until the assembly drops into position. 5. Turn locking ring 1/4 turn to secure the 2750 assembly. (The ring is locked when the line on the ring and the line on the body of the 2750 are aligned.) Locked In-Line Sensor and Electrode Removal To remove electronics assembly only: Turn locking ring 1/4 turn; lift assembly straight up. To remove electrode from the pipe: Remove electronics assembly, then unthread retaining cap; pull electrode straight up. To remove the complete 2750 system: Hold locking ring in place. Unthread retaining cap and pull electrode straight up. page 4 of 8 CAUTION! Do not remove the electrode from a pressurized pipe. Wear appropriate protective clothing when working with the system.
2750-3 Submersible ph Sensor Assembly and Installation 1. Insert electrode into base of the 2750-3 and turn until keyed contacts are seated. 2. Thread retaining cap over electrode and hand-tighten onto 2750. 3/4 in. NPT threads or ISO 7-1/R 3/4 threads 3. Attach 3/4 in. watertight pipe to the top of the 2750. Secure the threaded connection to prevent any leakage. For additional defense against possible accumulation of condensation at the back seal area of the sensor, fill the lower 3-4 inches (75-100 mm) of conduit or extension pipe with a flexible sealant such as silicone. A light coat of non-petroluem based lubricant on the o-ring with will ease installation. Fill with 3 to 4 in. of sealant Note: Keep the electrical interconnection between electrode and sensor electronics dry and clean at all times. Use standard installation hardware to connect the submersible 2750-3 directly to external equipment. OR The 8052 NPT Mount Junction box (or 8052-2 with Local EasyCal) connects to 3/4 in. pipe or conduit and provides convenient wiring termination. OR The 8050 Universal Mount junction box (or 8050-2 with Local EasyCal) mounts flat onto a wall or can be strapped to a post or pipe. 1/2 in. NPT threads Fill with 3 to 4 in. of sealant page 5 of 8
Wiring the submersible 2750 direct to external equipment Use the wiring diagram below for systems without a +GF+ SIGNET junction box. Wiring the submersible 2750 with a junction box +GF+ SIGNET junction boxes include a terminal block inside the yellow cover. For Loop output, use 2 cond w/shield, 22-24 AWG For S 3 L output, use 3 cond w/shield, 22-24 AWG Out to external equipment + SW1 Run SW2 Cal BLK D1 Fill with 3 to 4 in. of sealant Output to external equipment - S RED WHT SHLD Input from 2750 2750 wire color Terminal block label 4-20 ma Output Function S 3 L Output Function BLK + Loop + (12-24 VDC) V+ (5 VDC ±1%) RED WHT - No connection Loop - Data Out/Calibrate Signal Ground SHLD S Earth Ground Earth Ground SW1 Run SW2 Cal + BLK D1 Output to external equipment - S RED WHT SHLD The sensor input for the in-line 2750 is factory-connected Wiring the in-line 2750 page 6 of 8
Calibration The 2750 ph/orp Sensor is factory calibrated for out-of-the-box accuracy when used with new +GF+ SIGNET 275x ph and ORP electrodes. Once in service, periodic cleaning and calibration is necessary to compensate for changes in electrode output as a result of coating and aging. The required frequency is application-dependent, but once/week for cleaning and twice/month for calibration is good for a start. The 2750 ph/orp Sensor can also be used as a blind transmitter (provides 4 to 20 ma output but has no local display of ph or ORP value) so Local EasyCal is available as an option to facilitate calibration in the field. This accessory includes a single push-button and an LED, which are located beneath the yellow cap inside the conduit adapter or junction box. There is also a two-position switch, labeled Run and Cal. This switch must be in the Run position during normal operation and during calibration if the 4 to 20mA output of the 2750 is being utilized. If the S 3 L output is being used, and if the operator chooses to perform system calibrations using the Local EasyCal accessory, then the switch must be placed in the Cal position during calibration only. Return the switch to the Run position once calibration is complete. SW1 Run SW2 Cal SW1 SW2 D1 Local EasyCal button RUN/CALIBRATE switch for S 3 L system Local EasyCal Indicator (green LED) + BLK RED D1 Calibration Tips: As electrodes age their reaction time becomes slower. And if there is no local display of the measured values to help the operator determine whether an electrode s output is settled enough for calibration, it may be prudent to allow extra time before and between the steps of the procedure below. For example, changing temperatures can have a significant effect on electrode output, so it is recommended to perform calibration at room temperature. Therefore, the operator should allow enough time for an electrode coming out of a hot or cold process to achieve room temperature prior to calibration. This could take several minutes, depending on temperature, and should be done in tap water. Some suitable cleaning agents such as 5% HCl or even dishwashing detergent can temporarily shock an electrode. It is good practice to rinse an electrode thoroughly after each cleaning and then allow it to soak in a calibration solution or tap water for several minutes prior to calibration. The electrical interconnection between electrode and sensor electronics must remain dry and clean at all times. Local EasyCal Calibration Procedure: The first step (Reset) is recommended each time an electrode is replaced, but is not necessary upon initial installation or periodic calibration. In fact, for periodic calibration it is best for the electrode/sensor assembly to remain intact to minimize the possibility of moisture or other contamination from entering the electrical interconnection area. 1. Reset the 2750 ph/orp Sensor to factory calibration. With no electrode connected to the Sensor, press and hold the button until the LED comes on steady then goes off again (approx. 10 seconds). When the LED goes off, release the button; reset is complete. 2. Connect an electrode to the 2750 ph/orp Sensor. 3. Place the electrode/sensor assembly into a calibration solution as follows: (If the electrode is healthy, then the 2750 will automatically recognize the solution, so the order in which the operator selects solutions for calibration is of no consequence.) For ph calibration, use any two of these international standards: ph 4.0, 7.0 or 10.0 buffer solutions. To produce standards for ORP calibration, mix the chemical Quinhydrone into ph 7.0 and 4.0 buffers to saturation (1/8g per 50ml). Regardless of the size of the container used for calibration, one inch of solution is adequate to completely submerge the tip of the electrode. Allow at least 30 seconds for the electrode response to stabilize. 4. Press and hold the button for approximately 8 to 10 seconds. During this time, the LED will come on steady then go back off. (If the LED blinks several times rapidly, the calibration was not successful. See the troubleshooting section.) 5. Remove the electrode/sensor assembly from the first calibration solution, rinse the electrode with tap water or DI water, and place it in a second solution. Allow at least 30 seconds for the electrode response to stabilize. 6. Press and hold the button for approximately 8 to 10 seconds. During this time, the LED will come on steady then go back off. (If the LED blinks several times rapidly, the calibration was not successful. See the troubleshooting section.) 7. Calibration is complete; return the unit to service. page 7 of 8
Troubleshooting LED and Output Condition Possible Causes Suggested Solutions Current Out: LED off, current output is 3.6 ma S3L: Temp out is +999.9 No electrode installed Bad/dirty contacts between electrode and 2750 Install electrode Check interconnection between electrode and 2750, clean contacts During Local EasyCal, the LED blinks rapidly for 4 seconds. The current output is frozen at some value. The buffer solution is outside of the accepted tolerance for the 2750 The electrode is depleted (> 1.1 ph or 65 mv offset) ph system: Use fresh 4 ph, 7 ph, or 10 ph buffer and restart the calibration. ORP system: Use fresh 4pH and 7 ph buffer solution saturated with quinhydrone. Replace the electrode. Ordering Information Mfr. Part No. Code Description 3-2750-1 159 000 744 In-line Sensor Electronics w/junction Box 3-2750-2 159 000 745 In-line Sensor Electronics w/jct. Box & Local EasyCal 3-2750-3 159 000 746 Submersible Sensor Electronics with 15 ft. cable, 3/4 in. NPT threads 3-2750-4 159 000 842 Submersible Sensor Electronics with 15 ft. cable, ISO 7-1/R 3/4 threads 3-2754 159 000 747 Flat ph Electrode 3-2754-HF 159 000 748 Flat ph Electrode, HF Resistant 3-2755 159 000 749 Flat ORP Electrode 3-2756 159 000 750 Bulb ph Electrode 3-2756-DI 159 000 751 Bulb ph Electrode, DI Resistant 3-2757 159 000 752 Bulb ORP Electrode Accessories Mfr. Part No. Code Description 3-8050-1 159 000 753 Universal Mount Junction Box 3-8050-2 159 000 754 Universal Mount Jct. Box w/local EasyCal 3-8052-1 159 000 755 3/4 NPT Mount Junction Box 3-8052-2 159 000 756 3/4 NPT Mount Jct. Box w/local EasyCal 3-2759 159 000 762 ph/orp Simulator/System tester 3-2759.391 159 000 764 Adapter cable for use with 2750 3-2759.393 159 000 765 Adapter cable for use with 2720 3-0700.390 198 864 403 ph Buffer Kit P31515-0P200 159 000 630 Universal Pipe Adapter PVC P31515-0C200 159 000 631 Universal Pipe Adapter CPVC P31515-0V200 159 000 459 Universal Pipe Adapter PVDF 5523-0322 159 000 761 Cable, 3-conductor shielded 22AWG (per ft) SIGNET Signet Scientific Company, 3401 Aerojet Avenue, El Monte, CA 91731-2882 U.S.A. Tel. (626) 571-2770 Fax (626) 573-2057 For Worldwide Sales and Service, visit our website: www.gfsignet.com Or call (in the U.S.): (800) 854-4090 GEORGE FISCHER +GF+ Piping Systems 3-2750.090/(B-8/01) English Scientific Company 2001 Printed in U.S.A. on Recycled Paper page 8 of 8