Related Manuals for eDAQ EA168
Summary of Contents for eDAQ EA168
- Page 1 D A Q Am p User Ma nua l Quad pH/mV Amp Channel 1 Channel 2 Channel 3 Channel 4 On-line On-line On-line On-line ® e-corder www.eDAQ.com...
- Page 2 Changes may have been made to the software and hardware it describes since Document Number: U-EA168-1005 then: eDAQ Pty Ltd reserves the right to alter specifications as required. Late-breaking information Copyright © October 2005 may be supplied separately. Latest information and...
-
Page 3: Table Of Contents
A Technical Aspects How to Use this Manual 2 Quad pH/mV Amp Operation 27 Checking the Quad pH/mV Amp 2 Technical Description 27 .eDAQ Amps 2 B Troubleshooting 2 The pH/mV Amp C Specifications The Front Panel 6 The Electrode and Reference Inputs 6... - Page 4 Quad pH/mV Amp...
-
Page 5: Overview
C H A P T E R O N E Overview The eDAQ Quad pH/mV Amp is designed to work with an e-corder system, recording signals from: • pH electrodes (either combination, or half cell electrodes) • potentiometric ion selective electrodes (ISEs) •... -
Page 6: How To Use This Manual
Amps. The Quad pH/mV Amp is designed for recording signals from up to four pH and other potentiometric electrodes. As with other eDAQ Amps, it is designed to be operated under full software control and is automatically recognized by Chart or Scope software which controls its gain range, signal filtering, and other settings. - Page 7 Also provides DC excitation • GP Amp , suitable for high output sensors requiring a high impedance single ended or differential amplifier. Also provides DC excitation. See our web site at www.eDAQ.com for more information. Chapter 1 — Overview...
- Page 8 Quad pH/mV Amp...
-
Page 9: The Ph/Mv Amp
C H A P T E R T W O The pH/mV Amp This chapter describes how to connect and use your eDAQ Quad pH/mV Amp. IMPORTANT: Always make sure that the e-corder is turned off before you connect or disconnect the Quad pH/mV Amp. Failure to do this may result in damage to the e-corder and/or the pH/mV Amp. -
Page 10: The Front Panel
The Front Panel The front panel of the Quad pH/mV Amp is shown in Figure 2–1. The Electrode and Reference Inputs The BNC input connectors marked ‘E’ of the pH/mV Amp provide connection for combination pH, ISE or ORP electrodes. Combination electrodes have an internal reference and no separate reference electrode is required. -
Page 11: The Back Panel
Channel 4 Channel 3 Channel 2 Channel 1 No user serviceable parts inside. Refer servicing to qualified service personnel. Input Made in Australia by eDAQ Pty Ltd. Output DB–9 pin, I C connectors C control signals Power lines C control signals Figure 2–3... -
Page 12: I 2 C Connector
C bus’ connectors labelled Input and Output. The Input connector enables connection to the e-corder (or to the output of other eDAQ Amps). This connection provides power to the Quad pH/mV Amp and carries the various control signals (for gain range and filter selection) to and from the e-corder. -
Page 13: The Ph/Mv Amp Self Test
C output of one eDAQ Amp to the I C input of the next, as in Figure 2–5. The signal outputs of each eDAQ Amp are connected to an input channel of the e-corder. The pH/mV Amp Self Test After you have installed the software, connected the e-corder to a... -
Page 14: Using Chart And Scope
Using Chart and Scope Setting up the Quad pH/mV Amp When the Quad pH/mV Amp is connected to an e-corder input and successfully installed, the pH Amp… menu command appears in the Chart software Channel Function pop-up menu, Figure 2–6. In Scope software, the button appears in the Input A (or Input B) panel, see... - Page 15 Select input e-corder input Pause/Resume buttons Figure 2–7 channel channel number The pH/mV Amp pH dialog box, for previewing a signal (Chart software on a Gain range Windows Computer) (sensitivity) Select filter Average signal amplitude Preview signal Invert signal Drag labels and tick marks to adjust axis e-corder input Gain range...
- Page 16 Signal Display The input signal is displayed so that you can see the effect of changing the settings. The average signal value is displayed at the top left of the display area. Slowly drifting signals (as from pH electrodes) will be represented quite accurately, whereas quickly changing signals will be displayed as a solid dark area showing only the envelope (shape) of the signal formed by the minimum and maximum recorded signals.
- Page 17 Where multiple point calibration (more than two points) is required, use the Multiple Point Calibration extension. Both the pH Calibration extension and Multiple Point Calibration extensions can be obtained from the eDAQ website (www.eDAQ.com). Chapter 2 — The pH/mV Amp...
- Page 18 Quad pH/mV Amp...
-
Page 19: Electrode Calibration
Multiple point (i.e. more than two points) linear or non-linear calibration can be performed with the Multipoint Calibration extension. Both the pH and Multipoint Calibration extensions can be downloaded free of charge from the eDAQ website (www.eDAQ.com). Quad pH/mV Amp... -
Page 20: Signal Calibration
Signal Calibration Choosing the pH... command (available after installing the pH Calibration extension) from a channel pop-up menu accesses the Electrode Calibration dialog box, Figure 3–1 Figure 3–2. If a region of the electrode signal has first been selected in the Chart window then that region will also appear in the display area of the Electrode Calibration dialog box. - Page 21 Ionic charge Units pop-up Decimal places Raw signal Standard Calibration Figure 3–1 pop-up menu menu selection values buffer values report The Electrode Calibration dialog box of the pH Calibration Extension (Windows) Choose the pH Calibration… Temperature View electrode response, Selected signal from Select region of command from the compensation...
- Page 22 Figure 3–3 Selection of raw mV data from two buffer solutions, for use in electrode calibration ➊ ➋ Figure 3–4 Selecting different regions of the electrode signal ➍ ➌ ➊ intersection with the signal (Figure 3–4, ). If you select an area, drag the pointer (mouse) across the signal, the arrow shows the average amplitude of the signal, and two markers,...
- Page 23 Click on arrow to enter average signal value Enter buffer pH Figure 3–5 Performing two point electrode calibration Select region of signal for first buffer Results of single point calibration Click on arrow to enter Enter second buffer pH average signal value Results of Select region of double point...
- Page 24 Figure 3–6 Defining new unit names Enter the unit name Units pop-up menu Delete unwanted units by choosing Delete Unit… from the pop-up menu. Set the number of decimal places to be displayed for cursor readings of the calibrated signal, by clicking the arrows, (Figure 3–1 Figure...
-
Page 25: Temperature Compensation
Calibration Temperature You must also enter the temperature of the standard buffer solutions, . Please remember that the pH value of a buffer solution is temperature dependent and that the correct buffer value should be used at that temperature. Temperature Compensation For the most exacting work, both calibration and experimental measurements are performed in a thermostatted glass reaction vessel maintained at a known temperature to within ±0.05 °C. -
Page 26: Automatic Temperature Compensation
(ATC). Using a suitable temperature probe and amplifier (for example the eDAQ Thermocouple Pod) the temperature signal can be recorded on a a spare e-corder channel. When the Automatic option is chosen, the pH extension will use temperature data from one of the Chart channels to correct the pH channel for variations in temperature. - Page 27 Figure 3–9 Uncalibrated temperature channel warning alert Select suitable range: 5 V up to 100 °C Select Temperature from Figure 3–10 2 V up to 40 °C the channel menu Previewing the temperature signal and setting up units for the temperature channel Preview of temperature signal...
-
Page 28: Isopotential Point
Isopotential Point The isopotential point of the electrode is the potential which remains constant as the temperature changes, see Figure 3–12. Most pH electrodes are constructed so that the isopotential point is about 0 mV (which for most pH electrodes also corresponds to pH 7). But it is not uncommon to find, even in new pH electrodes that the isopotential point is actually anywhere between ±50 mV and that this value changes as the electrode ages. -
Page 29: Manual Compensation Response
Calibration point Figure 3–11 The Electrode Response dialog box Single point calibration uses an ideal Nernstian slope Calibration points Print calibration report Calibration points Double point calibration Copy calibration report buttons and pop-up menu next to the axes can also be used for scaling. -
Page 30: Removing The Calibration
Response at 65 °C Isopotential point Response at 25 °C Figure 3–12 Electrode Response dialog box when using manual temperature compensation. Printing or Copying Use the buttons to copy the electrode response graph for pasting to a word processor document, or to print a quick report. -
Page 31: A Technical Aspects
Quad pH/mV Amp Operation The Quad pH/mV Amp and other eDAQ Amps have been designed to be used with an e-corder system. The pH/mV Amp is effectively an extension of the e-corder’s analog input channels. It provides: •... - Page 32 BNC-to-BNC cables, through which the amplified and filtered signal is sent to the e-corder. The overall operation of the pH/mV Amp can be better understood by referring to Figure A–1. The E input is used for combination electrodes where the reference electrode is connect to the cable shield.
-
Page 33: B Troubleshooting
A P P E N D I X Troubleshooting If you experience any difficulty with the Quad pH/mV Amp use this section to try to resolve the problem. In the majority of cases, the problem can usually be fixed by ensuring that the connecting cables are correctly connected and firmly attached and the re starting the Chart or Scope software. - Page 34 Quad pH/mV Amp...
-
Page 35: Specifications
A P P E N D I X Specifications Quad pH/mV Amp pH/mV Amplifier: Four. High impedance, electrometer type. Galvanically isolated. Input range: ±2 V Secondary ranges: ±1000, 500, 200, 100, 50, 20, 10, 5, 2 mV, supplied by e-corder Input resolution: 16 bits, 0.0015% of range Input impedance:... -
Page 36: Control Port
60 × 150 × 200 mm 2.4 × 5.9 × 7.9 inches Weight: 1.5 kg (3.3 lb) Operating conditions: 0 – 35˚C 0 – 90% humidity (non–condensing) eDAQ reserves the right to alter these specifications at any time. Quad pH/mV Amp... -
Page 37: D Electrode Behavior
A P P E N D I X Electrode Behavior The Nernst Equation Most pH and ion selective electrodes exhibit behavior that closely follows the Nernst equation which describes the relationship between potential, ion activity (≈ ionic concentration), and temperature. ... -
Page 38: Electrode Response
Electrode Response If two solutions of known pH are measured then these values can be used to construct a linear plot to determine E and electrode slope. The percentage Nernstian response of the electrode is given by: response = 100% × slope /slope observed calculated... -
Page 39: Non-Linear Calibration
on rearranging terms: pH = (E – E )/slope pH = (E – E )/slope where slope = –2.303RT /nF; and slope = –2.303RT At the isopotential point both potential and pH are constant for both T and T , that is E = E , and pH = pH . - Page 40 In either case, the Chart Multipoint calibration extension can be used for non-linear electrode calibration. See our web site, at www.eDAQ.com for more information. Quad pH/mV Amp...
-
Page 41: Index
6 report 26 undoing 26 calibration temperature 21 checking the Quad pH/mV Amp 2 GP Amp 3 connecting multiple eDAQ Amps 9 C connector 8 eDAQ Amps Ionic Charge menu 20 Bridge Amp 3 ISE electrodes GP Amp 3... - Page 42 – manual temperature compensation 21 Units pop-up menu 19 user modification 27 Nernst equation 20 Nernstian response 34 View Response button 24 non-linear calibration 35 warranty conditions 27 pH Amp dialog box 11 filtering 13 setting the sensitivity 12 – setup 10 Use with Chart or Scope 10 –...
-
Page 43: License & Warranty
(on one year from the date of purchase. eDAQ Pty Ltd one computer for data acquisition with a e-corder will repair or replace defective equipment as hardware unit, and on a second computer for the appropriate. -
Page 44: Technical Support
Jurisdiction eDAQ Pty Ltd is bound by the laws of New South Wales in Australia, and any proceedings shall be heard by the Supreme Court of New South Wales in Australia.
Need help?
Do you have a question about the EA168 and is the answer not in the manual?
Questions and answers