Related Manuals for eDAQ e-corder pH/mV Amp
Summary of Contents for eDAQ e-corder pH/mV Amp
- Page 1 D A Q A m p U s e r Ma n ua l pH/mV Amp Temperature Electrode Reference pH / mV Amp ® e-corder www.eDAQ.com...
- Page 2 Changes may have been made to the software and hardware it describes since Document Number: U-EA165-1103 then: eDAQ Pty Ltd reserves the right to alter specifications as required. Late-breaking information Copyright © November 2003 may be supplied separately. Latest information and...
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Page 3: Table Of Contents
1 Overview Removing the Calibration 30 How to Use this Manual 2 A Technical Aspects Checking the pH/mV Amp 2 . eDAQ Amps 2 pH/mV Amp Operation 31 Technical Description 32 2 The pH/mV Amp B Troubleshooting The Front Panel 6... - Page 4 pH/mV Amp...
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Page 5: Overview
C H A P T E R O N E Overview The eDAQ pH/mV Amp is designed to work with an e-corder system, recording signals from: • pH electrodes • potentiometric ion selective electrodes (ISEs) • redox (or ORP, oxidation–reduction) potentiometric electrodes •... -
Page 6: How To Use This Manual
Manual on the Installer CD. eDAQ Amps The pH/mV Amp is part of a family of preamplifiers known as eDAQ Amps. The pH/mV Amp is designed for recording signals from pH and other potentiometric electrodes. - 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 pH/mV Amp...
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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 pH/mV Amp. IMPORTANT: Always make sure that the e-corder is turned off before you connect or disconnect the 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 pH/mV Amp is shown in Figure 2–1. The Electrode and Reference Input The BNC input connector of the pH/mV Amp provides connection for a pH, ISE or redox electrode. Combination electrodes (that is those with an internal reference) will only need to be connected to this input. -
Page 11: The Temperature Input
The Temperature Input The temperature input can be used with the 100 Ω platinum resistance (RTD) probe supplied with the unit. The Back Panel The back panel of the Potentiostat is shown in Figure 2–2. Temperature signal, BNC connector Figure 2–2 The pH/mV Amp back panel Temp Output... -
Page 12: The Signal Outputs
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 pH/mV Amp and carries the various control signals (for gain range and filter selection) to and from the e-corder. - Page 13 Temperature Figure 2–4 Electrode Reference Connecting a pH/mV Amp to an e-corder pH/mV Amp Input 1 Input 2 Input 3 Power Output Output Status Input 4 Trigger Electrode signal output C input Temp Output pH Output e-corder C output C connector cable C output C input Temp Output...
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Page 14: 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 15: Previewing The Signal
Figure 2–6 Accessing the pH/mV Amp controls Scope software Chart software connected pH/mV Amp, you should check the connections at this point, quit the application, then open it again. Choosing the pH Amp… menu command or clicking the button will bring up the pH Amp dialog box, which replaces the Input Amplifier dialog box for the channel (your Chart and Scope Software Manuals have details on the Input Amplifier dialog box). - Page 16 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 17 You can shift and stretch the vertical Amplitude axis to make the best use of the available display area (see the Input Amplifier dialog in the Chart Software Manual for further details). Changes made here update settings in the main window of the program. Setting the Range Use the Range pop-up menu to select the input range or sensitivity of the channel —...
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Page 18: Setting Up The Temperature Amp
Units Conversion. Where multiple point calibration (more than two points) is required, use the Multiple Point Calibration extension. Both extensions are available from the eDAQ website (www.eDAQ.com) For more information about Units Conversion, see the Chart Software Manual or Scope Software Manual. - Page 19 Gain range Select input e-corder input Pause/Resume buttons (sensitivity) channel channel number Figure 2–9 The temperature dialog box (Chart software on a Windows Computer) Average signal Amplitude amplitude axis Incoming signal Signal invert control Units calibration Chart Software Manual for further details). Changes made here update settings in the main window of the program.
- Page 20 Select suitable range: 5 V up to 100 °C Select Temperature from Figure 2–10 2 V up to 40 °C the channel menu The temperature dialog box (Chart software on a Macintosh Computer) Preview of temperature signal Pause/Resume button Access Units Conversion for 0 V = 0 °C and 5 V = 100 °C...
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Page 21: The Temperature Probe
you want to use.) The units conversion will only apply to subsequently recorded signals, so it is more limited than choosing units conversion on individual blocks or pages of data. For more information about units conversion, see the Chart Software Manual or Scope Software Manual, which are both located on the Installer CD. - Page 22 pH/mV Amp...
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Page 23: Ph Calibration Extension
Chart window. 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). pH/mV Amp... -
Page 24: Electrode Calibration
Electrode 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 25 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 Select region of View electrode response, Selected signal from command from the compensation...
- Page 26 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 ➌ ➍ 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 27 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 28 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...
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Page 29: 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 30: Automatic Temperature Compensation
Figure 3–8 Selecting temperature compensation Manual temperature compensation Automatic temperature compensation, with temperature measured on channel 2 37°C, or 65°C etc. MTC will alter the electrode response slope to suit the new temperature on the basis of the Nernst equation. Make sure that temperature compensation is enabled in the Temp. - Page 31 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...
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Page 32: 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 33: 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 34: 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 35: A Technical Aspects
Amp Operation The pH/mV Amp and other eDAQ Amps have been designed to be used with an e-corder system. The pH/mV Amp is an extension of the e-corder’s analog input channels. It provides: •... -
Page 36: Technical Description
I (eye-squared-sea) bus. This connection supplies power to the eDAQ Amp as well. eDAQ Amps are connected to the analog input channels of the e-corder via BNC-to-BNC cables, through which the amplified and filtered signal is sent to the e-corder. - Page 37 The temperature input is effectively a separate eDAQ Amp. It consists of a bridge circuit that is factory configured for use with RTD temperature probes. The pH/mV Amp comes supplied with an RTD temperature probe. The output from the temperature amplifier has been factory set with the supplied RTD probe to produce 0 –...
- Page 38 pH/mV Amp...
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Page 39: B Troubleshooting
A P P E N D I X Troubleshooting If you experience any difficulty with the 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 40 pH/mV Amp...
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Page 41: Specifications
A P P E N D I X Specifications pH/mV Amplifier Section pH/mV Amplifier: High impedance, electrometer type. Input ranges: ±200 µV to ±2 V full scale in 13 steps (combined e-corder and pH/mV Amp) Input resolution: 16 bits, 0.0015% of range Input impedance: Ω... -
Page 42: Control Port
50 × 76 × 260 mm 1.96 × 3.0 × 10.2 inches Weight: 0.8 kg (1.8 lb) Operating conditions: 0 – 35˚C 0 – 90% humidity (non–condensing) eDAQ reserves the right to alter these specifications at any time. pH/mV Amp... -
Page 43: 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 44: 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 45: 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 46 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. pH/mV Amp...
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Page 47: Index
30 filtering 13 undoing 30 front panel calibration temperature 25 pH/mV Amp 6 checking the pH Amp 2 connecting multiple eDAQ Amps 10 GP Amp 3 eDAQ Amps Bridge Amp 3 C connector 8 GP Amp 3 pH Amp 2... - Page 48 ISE electrodes automatic 26 – isopotential point 28 manual 25 – isopotential point 28 troubleshooting 35 – manual temperature compensation 25 Units pop-up menu 23 user modification 31 Nernst equation 24 Nernstian response 40 View Response button 28 non-linear calibration 41 warranty conditions 31 pH Amp 2 dialog box 12...
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Page 49: License & Warranty
Each separate purchase of the eDAQ software licenses it eDAQ Pty Ltd warrants the pH/mV Amp, to be free to be used on two computers at any given time (on of defects in material and workmanship for one year one computer for data acquisition with a e-corder from the date of purchase. -
Page 50: 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.