Instruction Manual pH 500 LCD Transmitter 2-wire pH/ORP Transmitter with Display Technology Made Easy ... 68X216829 03/02 version 1 Preface This manual serves to explain the use of the pH 500 transmitter. It functions in two ways, firstly as a step by step guide to help you to operate the transmitter. Secondly, it serves as a handy reference guide. It is written to cover as many anticipated applications of the transmitter as possible. If there are doubts in the use of the transmitter, please do not hesitate to contact the nearest Authorized Distributor. Eutech Instruments/ Oakton Instruments will not accept any responsibility for damage or malfunction to the transmitter caused by improper use of the instrument. Remember to fill in the guarantee card and mail it back to your authorized distributor or Eutech Instruments Pte Ltd. The information presented in this manual is subject to change without notice as improvements are made, and does not represent a commitment on the part of Eutech Instruments Pte Ltd/ Oakton Instruments. Copyright © 2002 Updated on Mar 2002. All rights reserved. Eutech Instruments Pte Ltd/ Oakton Instruments TABLE OF CONTENTS 1 2 2.1 2.2 3 3.1 3.2 4 4.1 4.2 5 5.1 5.2 5.3 5.4 6 6.1 6.2 6.3 6.4 6.5 6.6 7 8 9 10 11 12 13 INTRODUCTION PREPARATION Power Supply Requirements Connecting the Electrode and Temperature Probe INSTALLATION Wall Mount Panel Mount DISPLAY AND KEYPAD FUNCTIONS Display Keypad CALIBRATION Preparing the Transmitter for Calibration pH Calibration Relative mV Calibration Temperature Calibration ADVANCED SETUP FUNCTIONS Offset Setting (Unavailable in ORP mode) Output Range Setting Temperature Compensation Setting (Unavailable in ORP mode) HOLD Current Setting Out-of-Range Current Setting Configuration PROBE CARE AND MAINTENANCE TROUBLE SHOOTING GUIDE SPECIFICATIONS TECHNICAL DIMENSIONS ACCESSORIES WARRANTY RETURN OF ITEMS 2 3 4 4 5 6 6 7 8 8 9 10 10 11 11 12 13 15 15 16 17 19 20 21 22 24 24 1 2 1 INTRODUCTION Thank you for selecting a Eutech Instruments/ Oakton Instruments transmitter. The pH 500 pH/ORP Transmitter is a microprocessor-based instrument that is designed to be sturdy and user-friendly. It is capable of measuring pH, mV and temperature. This transmitter has many user-friendly features ­ all of which are completely accessible through the water-resistant membrane keypad. Your transmitter includes an instruction manual and a warranty card. Please read this manual thoroughly before operating your transmitter. MEAS READY . . pH ATC 1 Preparation Remove screws from the four corners at the back of the Transmitter, and remove back cover. Connectors should be exposed as follows: All wiring is done on the detachable 9-pin connector. Using a suitable screwdriver, loosen screws from top of connector. When inserting the wires, always hold connector with top screws facing up. 1.1 Power Supply Requirements This transmitter requires a 12 to 24V DC power supply. Other Transmitters and/or a chart recorder may be connected in series. Insert positive loop wire from power supply to pin 1, tighten screw. Insert negative loop wire to pin 2, tighten screw. This wire may be linked to the positive terminal of next transmitter (pin 1) / Chart recorder or to negative terminal of power supply. 2 1.2 Connecting the Electrode and Temperature Probe To connect the pH or ORP electrode: The Eutech Instruments pH transmitter uses any standard pH or ORP. Remove BNC connector from cable. Two wires will be exposed: Strip insulation, just enough to expose bare wires. IMPORTANT: For pH/ORP sensing cable, remember to strip the inner black layer (screen) and expose the clear plastic sheath. Insert pH sensing cable into pin 9 of connector. Tighten screw. Insert pH reference cable into pin 7 of connector. Tighten screw. To connect temperature probe: For Automatic Temperature Compensation (ATC), this transmitter requires a temperature probe, Pt 100, 3-wire. 3-wire probe: Insert brown wire to pin 4 of connector. Tighten screw. Insert red wire to pin 5 of connector. Tighten screw. Insert green wire to pin 6 of connector. Tighten screw. 2-wire probe: Take a small length of wire and short pins 4 and 5 of connector. Insert red wire into pin 5 of connector and tighten screws. Insert green wire to pin 6 of connector. Tighten screw. IMPORTANT: Temperature probe should always be together with pH probe, even during calibration. Make sure no bare wires are exposed and all screws are tightened for proper contact. To connect Potential Matching Pin (Liquid electrical interferences): Connect the additional wire from the electrode to pin 3. Transmitter must be configured to `Symmetrical mode of operation' - Please refer to `Advanced Setup Functions', Section 6.6.2 - `Selecting Asymmetrical or Symmetrical Mode of Operation. Insulation Screen pH reference Clear sheath pH sensing 3 2 INSTALLATION 2.1 Wall Mount 4 2.2 Panel Mount 1. Prepare panel cut-out of 92.0 mm by 92.0 mm Panel (side) 2. Remove back cover of transmitter and slide it through panel cut-out 4. Thread rods through lugs until transmitter is held in place against panel 3. Attach lugs to either side of transmitter 5 3 DISPLAY AND KEYPAD FUNCTIONS 3.1 Display The LCD has a primary and secondary display. · · The primary display shows the measured pH, mV or Relative mV value. The secondary display shows the measured temperature. In Calibration mode, pH buffer values are displayed here; while measured mV values are displayed in the ORP Calibration mode. 1 2 3 SETUP 15 14 READY HOLD MEAS CAL -. . . 888 ERR mV pH 4 5 6 7 8 9 13 -. . . 1888 10 ATC pH 12 1. SETup mode indicator 2. MEASurement mode indicator 3. CALibration indicator 4. mV indicator 11 6. Primary display 7. Temperature indicator 11. ERRor indicator 12. Probe indicator 13. Buffer indicator 8. pH buffer selection indicator 9. Automatic Temperature Compensation indicator 14. HOLD indicator 5. pH indicator 10. Secondary display 15. READY indicator 6 3.2 Keypad The four-button keypad allows easy and quick operations of the Transmitter. Key CAL Function Brings you directly into the Calibration mode. 1. If you were in pH Measurement mode, press CAL to enter pH Calibration mode. 2. If you were in mV Measurement mode, press CAL to enter mV Calibration mode. 1. 2. 3. ENT To scroll through the various submenus To increment/decrement values or toggle between options (in the SETUP/CAL modes) When pressed together, serves as escape function to return to MEAS mode from any point (CAL or SETUP modes). / 1. To confirm your calibration values in Calibration mode. 2. To confirm selections in SETUP mode. While in MEAS mode, pressing ENT takes you directly to SETUP submenu 7 4 4.1 CAL IBRATION Preparing the Transmitter for Calibration Before starting calibration, make sure you are in the correct measurement mode. When you switch on the transmitter, the transmitter starts up in the units last used. For example, if you shut the transmitter off in "mV" units, the transmitter will read "mV" units when you switch the transmitter on. Be sure to remove the protective electrode storage bottle or rubber cap of the electrode before calibration or measurement. If the electrode has been stored dry, wet the electrode in tap water for 10 minutes before calibrating or taking readings to saturate the pH electrode surface and minimize drift. Wash your electrode in deionized water after use, and store in electrode storage solution. If storage solution is not available, use pH 4.01 or 7.00 buffer solution. Do not reuse buffer solutions after calibration. Contaminants in the solution can affect the calibration, and eventually the accuracy of the measurements. The transmitter features two internationally recognized buffer standards. Select the buffer standard you require in the CAL mode Select from the following buffer options: · · First-point : pH 7.00 (USA buffer) or pH 6.86 (NIST buffer). Second point: pH 4.01, 9.18, or 10.1. NOTE: When transmitter is entered into the CAL mode, the 4/20 mA output current will be automatically held*. `HOLD' will be displayed on LCD. After Calibration and transmitter is returned to MEAS mode, the `HOLD' is automatically released. * Please refer to page 14, section 6.4 for more details. 8 4.2 pH Calibration A complete 2-point CAL is required for this Transmitter. If Calibration is aborted after 1st calibration point, transmitter reverts to previous Calibration data. 1. 2. Rinse probe thoroughly with de-ionized water or a rinse solution. Blot excess liquid. READY CAL HOLD Dip probe into calibration buffer. End of probe must be completely immersed into buffer. Stir probe gently to create a homogeneous sample. From pH MEAS mode, press CAL to enter pH calibration mode. CAL indicator will be shown. Primary display will show measured reading while secondary display will indicate the pH standard buffer solution. Press or keys to select either pH 7.00 (USA) or pH 6.86 (NIST) standard buffers. This is the first point, Offset calibration. Wait for measured pH value to stabilize. Press ENTER to confirm calibration. Transmitter is now calibrated to current buffer. Rinse probe with de-ionized water or rinse solution, and place in next pH buffer (pH 4.01, pH 9.18 or pH 10.01). Repeat steps 5 and 6. Upon successful Calibration, transmitter displays Slope (primary display, in mV) and Offset (secondary display, in pH) of electrode. Press ENTER to return to MEAS mode. Transmitter has been calibrated. Rinse electrode and proceed with measurements. . . CAL pH pH 3. READY HOLD . . pH 4. pH 5. CAL READY HOLD 6. . . pH pH 7. 8. CAL HOLD mV 9. . . pH NOTES: To exit from pH calibration mode without confirming calibration, press and keys together. If selected buffer value is not within ±1.0 pH from measured pH value: electrode and buffer icon blink and ERR annunciator appears in lower left corner of display. 9 4.3 Relative mV Calibration CAL READY HOLD R.mV 1. From the ORP MEAS mode, press CAL key. CAL indicator appears at top of LCD. Primary display shows relative mV reading and secondary display shows absolute mV value. CAL READY HOLD R.mV NOTE: If you have never calibrated relative mV or if the transmitter has been reset, the value shown in the primary display is the same as the absolute mV value. 2. Press or keys to enter the relative mV value that matches your desired reading (only the readings in the primary display changes). Press ENTER key to confirm. Transmitter will now display the offset in the readings. Press ENTER key to return to MEAS mode. 3. CAL READY HOLD R.mV 4. 4.4 Temperature Calibration Only available in the pH mode and ATC probe is available. Calibrate temperature probe only if temperature value displayed on transmitter is different from that of a calibrated thermometer. Temperature readings are only displayed Please refer to section 6.3.1 for further information. 10 5 ADVANCED SETUP FUNCTIONS The advanced setup mode lets you customize your transmitter's preferences and defaults. This transmitter features different sub groups that organize all setup parameters. The sub-groups are: 5.1 Offset Setting (Unavailable in ORP mode) As a result of the continuous measurement and the application concerned, it may not be convenient to remove the electrode for calibration. In such cases, an on-line Offset adjustment is offered. 1. Press ENT key. Transmitter displays `OFS'. Press ENT again. Upper display shows amount of offset, in terms of pH; lower display shows current measured pH value. Use or keys to introduce offset to pH readings. As the lower measured reading changes, upper display records the amount of offset. Maximum of ± 2.00 pH offset is allowed. Press both or keys together to return to ` MEAS ` mode. SETUP HOLD 2. SETUP READY HOLD . . pH pH 3. 11 5.2 Output Range Setting SETUP HOLD Output of pH 500 transmitter is via the 2-wire power supply loop. Both the 4 mA and 20 mA output can be assigned to specific pH or ORP values, for a more refined output. 1. Press ENT key and use or keys to scroll till LCD displays `r n g '. Press ENT again. Upper display shows pH value, `0.00' (or ­ 1000 mV) while lower display shows `r 4.0'. Assign pH or ORP value to 4 mA output current. Use or keys to change pHor ORP value. Press ENT to accept value. Upper display shows pH value,'14.00' (or 1000 mV) while lower display shows `r 20.0'. 2. 3. 4. 5. Assign pH or ORP value to 20 mA output current. Use or keys to change pH or ORP value. Press ENT to accept value. Press both or keys together to return to ` MEAS ` mode. 12 5.3 Temperature Compensation Setting (Unavailable in ORP mode) pH values other than pH 7.00 is affected by temperature. Under varying temperature conditions, use ATC to compensate pH values. If temperature of bath is constant, then select Manual Temperature Compensation. 5.3.1 Automatic Temperature Compe ...