USB DrDAQ User`s Guide
Contents
1. Oe ae PG mews 5 ns Bia noz PO ROARS OS Sound d Geepe Chews higa ho Ext ho EI AR FF i GO mae Pere a A typical finger click trace Problems Help is at hand Our technical support staff are always ready to answer your telephone call during office hours see our Contact Details 1 At other times you can leave a message on our support forum or send us an email usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 2 6 2 Displaying channels To display channels within the oscilloscope window move your cursor to the channel buttons which are located along the top of the oscilloscope screen File Edit Views Measurements Tools Help a adu dis A Gh 10mssaiv vy x1 F 20ks Ed 0 ofo DERRE IS Channel buttons p Sound de Scope r Ohms pH _ r Temp rl Light F bt1 r Be2 F bt F Ay Te 8 Add a channel by clicking on the sensor you d like to activate In this example we have activated the the Light sensor once activated the trace will appear and the button will be highlighted in blue File Edit Views Me ts Tools Help AUTO au dis 7 68 mlx Ells BM 11 of 2 DIRIMA RG O Bound gt aB r Scopej ohms pH Fiere E 6 lt 2 Flees 5 a 1 A 00 0 ee ry Bi J 900 FA fria da j j2. It is important that the readings are taken for both extremes of the sensor s operating input range to ensure accuracy For example A temperature sensor has an input range of 200 C to 200 C but we only want to use it between 5 C and 110 C Therefore this will be its operating input range The first calibration point should be close to 5 C so the sensor will be placed in melting ice which is known to be 0 C The second calibration point should be close to 110 C so the sensor will be placed in boiling water which is known to be 100 C It is rare that such a convenient range is available but the principle of two point calibration stays the same It is important to distinguish between the operating range and the full input range of the sensor since it would be far more difficult to calibrate the sensor between 200 C and 200 C and would yield no accuracy benefit for the user between 5 C and 110 C usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 37 Non Linear x Multi point Calibration You will need more than two points to describe a non linear response curve and therefore you will need to create a look up table experimentally Since you will be measuring a series of readings at unconfirmed intervals the only way to know the calibrated value is to perform the same measurement with both the sensor you are calibrating and a sensor which you know has
3. 2 What is the output of the sensor Can the sensor be plugged directly into the USB DrDAQ 3 Is the sensor already available on the USB DrDAQ or are there more suitable sensors out there Scaling Sensor Scaling Software It is necessary to create a scaling file so that the software can extract details about the sensor Details on creating scaling files can be found in the DrDAQ Scaling Files DDS 33 topic Scaling in software also provides an opportunity to perform a calibration 35 on the sensor which can compensate for any manufacturing irregularities Sensor Scaling Hardware With both these types of sensors it is essential that the USB DrDAQ displays an accurate representation of the property to be measured There are many factors to take into account when designing scaling circuitry Sensitivity The USB DrDAQ has 12 bit resolution over the 0 to 2 5 V input range This means the sensitivity is 2500 mV 2 12 0 611 mV To make the most of the resolution the signal output from the sensor should use as much of the input range of the USB DrDAQ as possible Linearity As illustrated below not all sensors have a linear response Linear Response An Example of Non Linear Response y x x A linear response is one whose output versus input graph is a straight line An example of this type of response is a photodiode Note a non linear response curve cannot be calculated using a simple y ax b formula An ex
4. You may use the EL029 to connect a simple single pole switch Such as a micro switch to USB DrDAQ You will need to obtain a switch and some insulated connecting wire Remember to keep magnets or magnetic fields away from the ELO29 when you use it with an external switch Magnetic fields will still make the internal reed switch operate overriding the open setting of the external switch To connect the switch follow these steps 1 Make sure that the leads from the external switch have about 5 mm of bare wire to form the connections 2 Remove the lid 3 Put the ELO29 on a firm flat surface such as a table top with the fixing screw facing up and the connection socket towards you 4 Unscrew the fixing screw 5 Lift off the lid of the ELO29 and put it and the screw to one side The lid should lift off easily 6 Connect the wire 7 Find the small terminal block with two screws in its top towards the back of the ELO29 circuit board 8 Loosen the screws in the terminal block Do not take them out altogether 9 Thread the two wires from the external switch through one of the holes in the bottom of the ELO29 usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 19 2 9 5 10 Note If you do not wish to use either of the two holes in the bottom of the EL029 case make a hole in the side of the case just big enough for the leads to pass through Take care not to damage the
5. Connect the pH electrode to USB DrDAQ and display pH using either PicoScope or PicoLog depending on which program you are calibrating for 2 Place the electrode in the first solution and wait for at least 30 seconds for the readings to stabilise gently stirring helps usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 17 3 4 Make a note of the reading and repeat the procedure for each of the buffer solutions do not forget to wash the probe clean before swapping from one buffer to another You should now have a table of readings similar to the one below pH Buffer value at 25 C Measured value from USB DrDAQ 4 01 406 O pH calibration with PicoLog As already mentioned you will need to note down the measured pH value and compare it with the actual value to create a lookup table Then follow the steps below SU BW 7 1 Go to Settings and click on Input Channels on the pull down menu 2 The converter input type will then be displayed Check settings and click OK You should now see the USB DrDAQ measurements box Select pH and click Edit Click Options from the Edit measurement box Now click on Scaling and select Look up table from the menu box Enter the real measured pH value below Raw and the actual value in Scaled similar to the table in the previous section Click OK for all open boxes and verify the calibrated pH readings Storing pH el
6. 9 1 2 9 2 2 9 3 External sensors Overview As well as the built in sensors USB DrDAQ has sockets for optional external sensors When a sensor is plugged in to the external sensor sockets the software detects it and automatically scales readings For example if a temperature sensor is plugged in readings are displayed in C or if a humidity sensor is plugged in readings are displayed in RH External sensors are optional extras so can be purchased at any time For an up to date list of the available external sensors consult the USB DrDAQ web site at http www DrDAQ com DD100 Temperature Sensor 15 DDO11 pH Electrodel 15 ELO29 Reed Switchs DD101 Humidity Sensor 19 DD103 Oxygen Sensor 24 DD100 Temperature Sensor High accuracy general purpose temperature sensor with a 2 metre lead Suitable for air surface or liquid measurements Range 10 C to 105 C Resolution at 25 C Accuracy at 25 C DDO11 pH Electrode Before using your electrode remove the storage bottle Size 2 120 mm Operating temperature 0 to 60 C Resolution 0 02 pH Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 16 Product information Using USB DrDAQ with pH Electrodes The pH input on USB DrDAQ is a very high impedance input that is suitable for use with any standard pH electrode For most applications no calibration is required just plug in an electrode and measure
7. and using the standard solutions Prepare your standard solutions before you start the calibration procedure Follow the instructions given by the manufacturers of the solutions you are using A slurry of undissolved chemical in your solution should improve the stability Make sure that all the containers you use for preparation are thoroughly clean before use as contamination of the solution will alter the humidity Do not use tap water to make up the solution as this is insufficiently pure use distilled and de ionized water Allow time for the solution to reach room temperature before use Always use fresh solutions to ensure that the chemicals have not become contaminated or degraded Allow the standard solutions and other equipment to reach the same temperature ideally 20 C before you start Measure humidity 1 Set up the equipment 2 Clean the equipment Make especially sure that the test container is clean rinse it out with distilled water 3 Put the test container into your insulated box The standard solutions may be harmful to your skin eyes or when swallowed Take all necessary precautions to avoid contact when preparing and using the standard solutions Caution It is very important that the standard solution does not enter the case of the DD101 The solution may damage the electrical components of the sensor 1 Put some of the standard solution into the test container The solution should occupy about 5 of the volu
8. case check that you have entered the calibration data correctly and repeat the process Once you have successfully calibrated your DD101 write the date on the label and stick the label on the sensor do not block the holes in the sensor with the label Testing Sensors You can check whether a sensor is working properly or not by running through the calibration procedure If you find that the sensor values differ from the standard values by more than 10 you may have a damaged sensor In this case contact Pico for assistance DD103 Oxygen Sensor The DD103 Oxygen Sensor is used to measure the percentage of oxygen in a gas The sensor plugs into the external sensor sockets of USB DrDAQ using the supplied cable usbdrdaq en Copyright 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 25 Specification Sensor Type Galvanic Cell lead oxygen with weak acid electrolyte Input Range 0 to 100 oxygen Accuracy Calibrated 3 0 over operating conditions range Response Times lt 15 seconds for 90 response lt 25 seconds for 97 response Max Humidity 0 to 95 Non condensing Operating Temperature 5 Cto40 C Storage Temperature 15 Cto50 C Setting up the oxygen sensor Since the Oxygen Sensor has an output of O mV at 0 oxygen a single point calibration 35 calibration can be carried out The procedure below guides you through setting up the oxygen sensor to work with PicoLog and calibrating it usin
9. copy and distribute the entire release in its original state but must not copy individual items within the release other than for backup purposes Liability Pico Technology and its agents shall not be liable for any loss damage or injury howsoever caused related to the use of Pico Technology equipment or software unless excluded by statute Fitness for purpose No two applications are the same Pico Technology cannot guarantee that its equipment or software is suitable for a given application It is your responsibility therefore to ensure that the product is suitable for your application Mission critical applications This software is intended for use on a computer that may be running other software products For this reason one of the conditions of the licence is that it excludes usage in mission critical applications for example life support systems Viruses This software was continuously monitored for viruses during production but you are responsible for virus checking the software once it is installed Support If you are dissatisfied with the performance of this software please contact our technical support staff who will try to fix the problem within a reasonable time scale If you are still dissatisfied please return the product and software to your supplier within 28 days of purchase for a full refund Upgrades We provide upgrades free of charge from our web site at www picotech com We reserve the right to charge f
10. field is not used by USB DrDAQ running PicoScope or PicoLog Units C Displayed on graphs MinValue 40 MaxValue 120 usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 35 Note For PicoScope these values will determine the maximum and minimum values displayed in Oscilloscope View For PicoLog these values determine what Maximum range is displayed in the Graph View set in the Graph Options dialog Places 1 Number of decimal places The options are 0 1 2 and 3 With places 1 the value 15 743 would be returned as 157 meaning 15 7 With places 2 the same value would be returned as 1574 Method 0 This specifies the scaling method O specifies table lookup and 1 specifies linear scaling Offset 0 Gain 1 These are the offset and gain values for linear scaling OutOfRange 0 This specifies what to do if the raw value is outside the range of the table lookup The options are O treat as a sensor failure 1 clip the value to the minimum or maximum table value 2 extrapolate the value using the nearest two table entries ScopeRange 1 25V This is used when scaling the scope channel It specifies the range of the scope channel that should be used Possible values are 10 V 5 V 2 5 V and 1 25 V NoOfPoints 32 This is the number of table lookup points Rawl 2 385 Raw value for the first point in the look up table The value is in V volts and should not be
11. greater than 2 500 V except when using the scope channel when the minimum and maximum values correspond to the selected range Scaled1i 30 Scaled value for the first point in the look up table The units are specified by the units parameter 2 10 6 Calibration You can adjust the calibration of the USB DrDAQ and its sensors using the Scaling Files 33 However all input channels of a USB DrDAQ are calibrated during manufacture Calibration involves measuring a known value such as the temperature of boiling water or the resistance of a known resistor or the values shown by a calibrated sensor then converting these values into the units you need Copyright O 2011 Pico Technology Ltd All rights reserved usbdrdag en 36 Product information Linear x Single Point Calibration When calibrating a sensor with a linear response curve it may only be necessary to perform a Single Point Calibration This only occurs in one circumstance One pair of values is known for example on the USB DrDAQ oxygen sensor The sensor is known to output OmV at 0 oxygen content Therefore we only need to find one other pair of values All we are doing here is changing the gradient of the response curve See the Oxygen Sensor 24 description for a full example Two Point Calibration A two point calibration should always be carried out if possible since it is the most accurate calibration method for a sensor with a linear response curve
12. AQ units include an RGB LED The colour of this LED can be changed to do this click the LED icon above the oscilloscope window The following drop down will appear Bju tm DANTAS Bea i 6 2 Flees Ny dal a pes C Enable LED Control O Clicking Enable LED Control will show the numerical values for the LED to be displayed RED 5 ori DINAR oa Bel Be2 rl ay ai 2 Z Enable LED Control Brightness 10 E Red RR 255 Green MEN o e Blue The colour of the LED is adjusted by dragging the individual colour and brightness sliders entering specific RGB values or clicking within the colour disc EAL or DANAS Ei r Et2 r Ee3 rl aal e Z Enable LED Control Brightness 100 eb Res O 20 Green NS 50 sue M 255 FE oA FP usbdrdaq en Copyright 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 11 2 6 7 Controlling the digital outs The USB DrDAQ device includes several digital connections To activate the digital outs ensure your accessory is connected both to the GND of the USB DrDAQ and the digital connection you wish to utilise To operate the connections click the digital out icon above the oscilloscope window The following drop down will a
13. If however you require very accurate pH measurements then you should calibrate the probe before use see below If you are using a pH probe and not getting the results you expect then the most probable cause is a defective pH electrode If cared for properly pH electrodes will last for a number of years see the instructions supplied with the electrode If they are not stored properly then they will be destroyed in a few weeks Trying to calibrate out errors from a defective probe will not work and may increase errors further pH measurement and temperature calibration The output from a pH electrode is proportional to absolute temperature kelvin A temperature difference of 10 C will cause the probe output to change by approximately 4 This is a major source of error with most pH meters and data loggers To minimise these errors a temperature sensor can be connected to Ext 1 and the DrDAQ will compensate for temperature changes Testing pH Electrodes The best way to test a pH electrode is to use pH buffers pH 4 pH 7 and pH 10 buffers are widely available If you do not have any pH buffers then distilled de ionised water will have a pH near 7 some still mineral water bottles have the typical pH printed on the label Most fizzy carbonated cola drinks have a pH in the 2 5 to 3 range With the pH electrode connected to USB DrDAQ display the pH channel using PicoLog Measure the pH of each buffer in turn Allow 30 seconds for th
14. Q User s Guide 33 2 10 5 PicoLog The following is a short example of how to activate an LED via a digital output on the USB DrDAQ using the Alarm function of PicoLog With USB DrDAQ connected and PicoLog open e Connect the LED to the GND connection on the USB DrDAQ and digital connection 2 refer to Connections Note Any digital connection can be used but we are using 2 in this example Choose File gt New settings Click OK Click OK Choose Converter type DrDAQ USB Click OK Click Add Next to Channel choose Temperature Choose Options Choose Alarm Select Enable Alarm Enter the Upper threshold 28 C Select Digital Output 2 Click the next four OK buttons Place a finger tip on the Temp sensor an alarm will trigger once the temperature goes above the upper threshold entered earlier when this happens the LED will illuminate along with the red alarm icon in PicoLog When you remove your finger the LED will extinguish once the temperature drops back below the upper threshold value USB DrDAQ scaling files DDS The DrDAQ driver has built in scaling for each of the built in and Pico supplied sensors You can incorporate scaling for your own sensors by adding a file called scaling dasla where scaling can be replaced with a name of your choice This file will contain the details of your sensor Each scaling file may contain more than one set of scaling data Each scaling must have a unique sc
15. You may have had an unsaturated solution some contamination in the solution inadequate sealing of your test container or possibly a damaged sensor Check your calibration routine If you still get large errors contact Pico for assistance If you are using a calibrated reference this should give values very close to those quoted for your standard solutions If these values disagree by more than a few percent suspect your calibration procedure When the two are in agreement use the values given by the calibrated reference as the correct figures for your data table Once you have your calibration data you must enter it into the Pico software to calibrate the sensor 1 Open the PicoLog Parameter Scaling Dialog 2 Start PicoLog Recorder 3 Click on Settings 4 Click on Input Channels the DrDAQ Measurements dialog appears 5 Select the input channel for the humidity sensor for example External 1 Humidity 6 Click on the Edit button the Edit DrDAQ Measurements dialog appears 7 Click on the Options button the Parameter Options dialog appears 8 Click on the Scaling button the Parameter Scaling dialog appears 9 Enter your calibration data 10 Pull down the Scaling Method list and select Table lookup 11 To start your calibration table click in the white rectangle the text cursor appears 12 Type in the value that you measured with the DD101 under Raw Type a space then enter the standard value under scaled Press the En
16. ale the input signal into the property that it represents Examples of digital out use PicoScope The following is a short example of how to activate an LED via a digital output on the USB DrDAQ using the Mask and Alarm functions of PicoScope With USB DrDAQ connected and PicoScope open Connect the LED to the GND connection on the USB DrDAQ and digital connection 2 refer to Connections Note Any digital connection can be used but we are using 2 in this example Within PicoScope activate the Temp channel only refer to displaying channels Under the Tools menu choose Masks gt Add Masks Choose Mask of Temp within the Available Masks area or click Generate if it doesn t show in the Library list Click Apply and choose OK Right click the oscilloscope window and choose Masks gt Edit Mask Within the mask dialogue adjust the two low values to 28 C Right click the oscilloscope window and choose Masks gt Exit Mask Edit Under Tools menu choose Alarms Under Event choose Mask s Fail ensure it is enabled Choose Add Under Action menu choose Digital Output Set Chann to Digital Output 2 and High Choose OK Click Apply and choose OK Start the trace and place the tip of a finger onto the Temp sensor on the USB DrDAQ The trace should rise and upon overlapping the mask the LED connected to digital connection 2 should illuminate usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDA
17. aling number contained in the Scale section heading A set of typical entries from a DDS file is shown below Scalel Resistor 1 LongName CustomTemperaturel ShortName TempC Units C MinValue 40 MaxValue 120 OutOfRange 0 Places 1 Met hod 0 IsFast Yes NoOfPoints 32 Rawl 2 385 Scaled1l 30 Raw32 1 32 Scaled32 100 Scale2 Resistor 2 2 Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 34 Product information LongName CustomTemperature2 ShortName TempF Units F MinValue 32 MaxValue 160 Scale3 Resistor 3 3 LongName CustomLight ShortName Light Units lux MinValue 0 MaxValue 20000 The meanings of the terms in the DDS file are as follows Scalel A unique number from 1 to 99 to identify this entry Pico created numbers are from 100 upwards Resistor 1 The ID resistor value in kiloohms In this example 1 represents 1k 2 2 represents 2k2 and so on For external sensors this resistor should be fitted in the sensor You must use one of the following resistors 1k0 2k2 3k3 5k6 7k5 or 10k The resistor must be 1 tolerance or better For internal sensors use the following virtual resistor values 1 Sound Waveform 1200 2 Sound Level 1300 3 Scope voltage 11500 4 Resistance 1600 s h uso 6 Temperature 1100 7 ige ooo LongName Temperature Used in PicoLog ShortName TempC This
18. already been calibrated Create a table of raw and scaled values similar to below x raw new sensor y scaled calibrated sensor Both PicoLog and PicoScope have the facility to manually enter look up tables see the respective help files You can also make a more permanent reusable scaling table with USB DrDAQ Scaling Files DDS 33 Copyright O 2011 Pico Technology Ltd All rights reserved usbdrdaq en 38 Software updates 3 Software updates Our software is regularly updated with new features To check what version of the software you are running start PicoScope or PicoLog and select the Help About menu The latest versions of PicoScope can check for updates automatically and will advise you if an update is available The latest version of all our software can be downloaded free of charge from the Pico Technology web site at http www picotech com Alternatively the latest software can also be purchased on disk or CD To be kept up to date with news of new software releases join our e mail mailing list This can be done from the main web site at http www picotech com usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 39 4 Glossary Analog bandwidth The input frequency at which the measured signal amplitude is 3 decibels below the true signal amplitude Buffer size The size of the oscilloscope buffer memory measured in samples The buffer allows th
19. ample of this type of response is an LDR Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 30 Product information Offsets x The above linear and non linear responses could have a voltage current resistive or other type of offset that may need taking into account It is quite usual to see offsets in output signals from sensors Sensor output The USB DrDAQ requires an input signal in DC volts or resistance The sensor in question could give an output in other units such as resistance current or AC volts Drift It is possible that the sensor output drifts over time This may involve recalibration of the sensor at set time intervals or some self calibration Hysteresis The sensor may give a different output value when rising to a voltage than when falling to a voltage This is difficult to eliminate and should be taken into account Once the sensor has been selected and all of the above has been considered the design of some scaling circuitry can begin There are many ICs on the market that can be purchased cheaply that deal with the above potential problems Look into these before re inventing the wheel and spending expensive development time designing a circuit that can be purchased for a few pounds usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 31 Some simple scaling examples Example 1 Interfacing a Resistive sensor 2 5 volts N
20. ct complies with the requirements of the specified Directives and Standards as listed below Technical documentation required to demonstrate compliance to the standards is available for inspection by the relevant enforcement authorities Product carries the CE mark Products covered by this Declaration PicoLog USB DrDAQ multi function data logger EU Directives covered by this Declaration 2004 108 EC Electromagnetic Compatibility Directive 2006 95 EC Low Voltage Equipment Directive The Basis on which Conformity is being Declared EN61010 1 2001 Safety requirements for electrical equipment for measurement control and laboratory use general equipment requirements EN61326 1 2006 EMC Immunity and Emissions for measurement control and laboratory equipment general requirements Test limits and frequencies are specified in CISPR11 and EN61000 4 CISPR11 2006 Industrial scientific and medical equipment radio frequency disturbance characteristics limits and methods of measurement Radiated and Conducted emissions Class A emissions CFR 47 2009 Code of Federal Regulations FCC part 15 Subpart B Frequency devices unintentional Radiators Radiated emissions standard Class A emissions EN61000 4 Radiated and Conducted Immunity including EN61000 4 2 1995 Electrostatic Discharge A1 1998 A2 2001 EN61000 4 3 2006 Radiated RF EN61000 4 4 2004 Electrical fast transients and bursts EN61000 4 6 2007 Conducted RF Alan To
21. ct information The Signal Input channel has 100 kQ pull up resistors to 2 5 V so that the input can be either a resistance or a voltage Here is a block diagram of a typical USB DrDAQ sensor 2 10 2 Powering the sensor A definition of a sensor is A device giving a signal for the detection or measurement of a physical property to which it responds The sensor s properties must be known before work can begin on designing some way of interfacing it to the USB DrDAQ sensor scaling There are two types of sensor Active Sensors These sensors require power excitation from an external source to generate an output signal Examples of active sensors include Property Sensor output Temperature Silicon Voltage Current RTD Resistance ___ Thermistor Resistance Force Pressure Strain Gauge Resistance _ Acceleration Accelerometer Capacitance __ Humidity Capacitor Resistance Light LDR Resistance __ Poston hvor JaC Voltage Passive Sensors These do not require any power to generate an output Typical examples are property sensor output Position Nariable resistor Light Intensity Photodiode usbdrdaq en Copyright 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 29 2 10 3 When selecting a sensor for an application you should consider the following The input is 0 2 5 V 1 Is the sensor Active or Passive If Active then can it be powered by the USB DrDAQ
22. ction for example laptops it must be assumed that USB DrDAQ is not protected by an earth in the same way a battery multimeter is not protected by an earth The scope channel on the USB DrDAQ has a maximum input voltage range of 10 V The maximum input voltage for all other inputs is 0 to 5 V Any voltage in excess of 30 V may cause permanent damage to the unit Your own sensors should draw no more than 100mA from the 5V the USB DrDAQ is not limited or protected so overcurrents or shorts could cause damage to the PC USB port The unit has no user serviceable parts repair or calibration of the unit requires specialised test equipment and must be performed by Pico Technology Limited or their authorised distributors Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 2 Introduction 1 3 Legal information The material contained in this release is licensed not sold Pico Technology Limited grants a licence to the person who installs this software subject to the conditions listed below Access The licensee agrees to allow access to this software only to persons who have been informed of these conditions and agree to abide by them Usage The software in this release is for use only with Pico products or with data collected using Pico products Copyright Pico Technology Limited claims the copyright of and retains the rights to all material software documents etc contained in this release You may
23. d USB DrDAQ User s Guide 27 2 10 2 10 1 Making your own sensors Overview Making your own sensors for USB DrDAQ is quite straightforward provided that you follow these guidelines Your own sensors should draw no more than 100mA from the 5V the USB DrDAQ is not limited or protected so overcurrents or shorts could cause damage to the PC USB port Designing a USB DrDAQ sensor overview Each external sensor socket has two channels One is an auto detect to inform the software which type of sensor it is and the other an analogue input that represents the sensor reading There are four pins on the External inputs This view is looking into the Ext socket on USB DrDAQ in the direction of entry of the plug Pin 1 Signal Input Pin 2 Ground Pin 3 Auto Detect Pin 4 Supply Voltage Suitable connectors to these external inputs are FCC 68 4 4 plugs Alternatively the USB DrDAQ sensor adapter break out box from Lascells can be used part number LA10 716 The pins are clearly labelled on the box Cid The range of the Auto Detect and Signal Input voltages must be between 0 and 2 5 volts This is a hardware limitation and any signals outside this range will not be read by the unit Any voltages greater than 30 volts fed directly into the device are likely to damage the unit and can cause errors with all other USB DrDAQ readings Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 28 Produ
24. e affinity of a substance for electrons Timebase The timebase controls the time interval that each horizontal division of an oscilloscope view represents There are ten divisions across the oscilloscope view so the total time across the view is ten times the timebase per division USB 2 0 Universal Serial Bus This is a standard port used to connect external devices to PCs The port supports a data transfer rate of up to 12 Mbps with USB DrDAQ Vertical resolution A value in bits indicating the precision with which the oscilloscope converts input voltages to digital values Oversampling 39 see above can improve the effective vertical resolution Voltage range The range of input voltages that the oscilloscope can measure For example a voltage range of 100 mV means that the oscilloscope can measure voltages between 100 mV and 100 mV Input voltages outside this range will not damage the instrument as long as they remain within the protection limits stated in the Specifications 14 table Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 40 Appendix A Declaration of Conformity 5 Appendix A Declaration of Conformity Pico Technology James House Marlborough Road Colmworth Business Park Eaton Socon St Neots Cambridgeshire Tec nology PE19 8YP United Kingdom Tel 44 1480 396395 Fax 44 1480 396296 EC Declaration of Conformity Pico Technology declares that the following produ
25. e oscilloscope to sample data faster than it can transfer it to the computer Device Manager Device Manager is a Windows program that displays the current hardware configuration of your computer On Windows XP or Vista right click My Computer choose Properties then click the Hardware tab and the Device Manager button Driver A program that controls a piece of hardware The driver for the oscilloscopes is supplied in the form of a 32 bit Windows DLL usbdrdaq d11l This is used by the PicoScope software and by user designed applications to control the unit Maximum sampling rate A figure indicating the maximum number of samples the oscilloscope can acquire per second The higher the sampling rate of the oscilloscope the more accurate the representation of the high frequency details in a fast signal Oversampling Oversampling is taking measurements more frequently than the requested sample rate and then combining them to produce the required number of samples If as is usually the case the signal contains a small amount of noise this technique can increase the effective vertical resolution 39 of the oscilloscope PC Oscilloscope A virtual instrument formed by connecting a PicoScope oscilloscope to a computer running the PicoScope software PicoScope software A software product that accompanies all PicoScope oscilloscopes It turns your PC into an oscilloscope spectrum analyzer Redox potential A measure in volts of th
26. e reading to stabilise and be sure to wash the electrode in clean water before swapping solutions If the pH measured is within 1 pH of the expected value then you can be fairly sure the electrode is working correctly If the readings are wrong then the electrode is probably defective Replacement electrodes are available from Pico Technology If you suspect that the pH input on USB DrDAQ may be defective then short out the BNC connector using a terminator plug The reading on the screen should be pH 7 if not then the most likely reason is that someone has calibrated the probe incorrectly Select File New Settings in PicoLog to delete the user calibration and return to the default calibration If the reading is still wrong then contact technical support Calibrating for accurate pH measurements As described above calibration is only required when accurate better than 0 5 pH measurements are required Calibration should be performed just before the measurements are made User calibration information is stored separately in PicoScope and PicoLog so if you wish to measure pH accurately with both programs 2 calibrations will be required To calibrate a pH electrode you will require at least 2 pH buffers pH 4 pH 7 and pH 10 buffers are widely available Calibration should be performed with the ambient temperature close to 25 C A container of clean water is also required to wash the electrode before moving it from one buffer to another 1
27. ecorded measurements for each standard solution Remember that you must provide at least two fixed points for calibration of the sensor ou usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 23 Create calibration data When the measurements are completed you need to make a written calibration table 1 From your recorded results find the place near the end of the measurement time where the readings are most stable 2 Write down these temperature and humidity readings for the standard solution in a table 3 Look up the humidity that the standard solution should give for the temperature that you have recorded Write this value in your table next to the value measured by the DD101 the manufacturer of the standard solution should have provided you with a table for humidities for different temperatures 4 Fill in entries for all the standard solutions you have measured You should end up with a table something like this Chemical Measured humidity Standard humidity Potassium chloride 81 85 20 C Magnesium nitrate 50 54 pare Magnesium chloride 30 33 OPC Keep this table for further reference It will be useful if you have to reset the software with the PicoLog Recorder New Settings command At this stage compare the measured and standard values If you find that the measured values differ from the standard values by more than 10 then there is something wrong
28. ectrodes If KCI solution is not available then any pH 4 buffer solution will be suitable for storing electrodes KCI is recommended because it is the substance inside the bulb of the electrode Tap water would be acceptable but is not ideal Do not under any circumstances use deionised or distilled water Copyright O 2011 Pico Technology Ltd All rights reserved usbdrdag en 18 Product information 2 94 ELO29 Reed Switch A reed switch sensor can be used to detect the presence of a magnetic field such as that from a bar magnet or an electromagnet Alternatively a simple single pole switch can be connected to terminals inside the ELO29 size 2 X45 x 28 mm Operating range 0 to 99 Maximum response time The ELO29 Reed Switch may be connected to either Ext 1 Ext 2 or Ext 3 on USB DrDAQ To determine the optimum position for the magnet Hold the ELO29 with its connecting socket towards you and the screw that fixes the lid facing up The best position for the magnet is about half way along towards the bottom of the right hand side of the ELO29 case The label on the bottom of the EL029 indicates this position When a magnet is in place next to the ELO29 the Reed Switch inside the ELO29 closes This is shown in PicoScope and PicoLog by a change from 100 switch open to 0 switch closed Note that this percentage is an indication of the proportion of the sampling period that the switch is in the open state
29. electrical components 11 Leaving enough free wire to make the connection secure the leads by looping them around the central boss of the EL029 case Alternatively put a tie wrap around the leads inside the case and near the hole Make sure that the leads are securely held in the EL029 12 Push the bare ends of the leads into the holes in the back of the terminal block There should be one lead in each hole 13 Tighten the screws in the terminal block and check that the leads are held firmly in place Do not overtighten the screws 14 Put the lid back on to the EL029 Make sure it is on the right way round 15 Tighten the fixing screw being careful not to overtighten it 16 Check the operation of the external switch Connect up the EL029 and make sure that PicoScope or PicoLog shows near to 100 when your external switch is open and 0 when it is closed DD101 Humidity Sensor DD101 Humidity Sensor measures humidity using a non condensing technique It has a short response time and plugs into the external sensor connections of USB DrDAQ Operating range 20 90 Relative Humidity Resolution 0 2 Relative Humidity Minimum response time 60 seconds with vigorous air movement Maximum response time 60 minutes in still air Caution Do not allow the DD101 sensor to become wet The DD101 is a non condensing sensor and liquid entering the case including condensation may damage it The DD101 may be connected to either E
30. etut esa debtius EEEE TESTTE Eo eU TVETEN ES KEETE EE n ta a 38 EC e ci i GRADO RR ER E NOR ERRA UR UND RR E AR CRS ARENA CRER NARRA concent 39 5 Appendix A Declaration of Conformity casa Actes at eal t ed acis AS Ca Sauk iced Saas dad ads 40 Tce gt ere ere eee Rene CNES Ree E CRER E TRE CRE AUS RI OR GRC REDOR CRE AOC CRE ER 41 Copyright O 2011 Pico Technology Ltd All rights reserved usbdrdag en pico j Technology USB DrDAQ User s Guide 1 1 1 1 1 2 Introduction Contact information Address Pico Technology James House Colmworth Business Park ST NEOTS Cambridgeshire PE19 8YP United Kingdom Tel 44 1480 396395 Fax 44 1480 396296 Web site www picotech com Safety warnings Warning triangle This symbol indicates that a safety hazard exists on the indicated connections if correct precautions are not taken Read all safety documentation associated with the product before using it Safety warnings USB DrDAQ ground is connected directly to the ground of your computer As with most oscilloscopes and data loggers this is done in order to minimise interference You should take care not to connect the ground screw terminal outer shell of BNC or exposed metalwork of USB DrDAQ to anything which may be at some voltage other than ground as doing so may cause damage to the unit If in doubt use a meter to check that there is no significant AC or DC voltage For computers that do not have an earth conne
31. g the oxygen in the atmosphere as a reference point calibration is necessary to use the sensor with 3 accuracy If you have not yet set up USB DrDAQ with PicoLog do so using the PicoLog help file before continuing below 1 Connect the Oxygen Sensor to the socket labelled Extl on the USB DrDAQ unit 2 From the File menu select New settings 3 Click OK 4 Check that USB DrDAQ is selected as the Converter type 5 Click OK 6 Click Add 7 Under Channel select External 1 The Scaling type will automatically change to oxygen 8 Go back to the main monitor view by clicking OK on the two dialog boxes USB DrDAQ should be receiving information from the oxygen sensor The sensor should be calibrated using the procedure below Calibrating the oxygen sensor Both PicoLog and PicoScope provide the facility to enter scaling 29 look up tables These instructions will concentrate on doing so in PicoLog for instructions on Custom Ranges in PicoScope see the PicoScope help file This is the information we have so far Raw Values after built Calibrated Values in Scaling File known to be true FR ee O 20 9 known oxygen in air at sea level Only one more value is needed to complete the look up table If you are measuring the normal atmosphere then this reading is currently displayed on the PicoLog monitor view Complete the table above with this value and follow the instructions below Select the Settings I
32. he device is ready to use usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 5 2 5 Getting started with PicoLog 2 5 1 Using PicoLog for the first time WL After installing the software click the new PicoLog icon Reade ON your Windows desktop When PicoLog is first loaded the following screen will appear TB PLW Recorder File Settings View EEE El inda Settings not defined vet Contents Use File New settings This view Alarm Channel Reading Units Guided tour About Under Help select the guided tour which will take you through the main functions in PicoLog Refer to Examples of digital in out use 32 gt for an example of PicoLog and the digital connections of USB DrDAQ Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 6 Product information 2 6 Getting started with PicoScope 2 6 1 Using PicoScope for the first time 1 After installing the software click the new PicoScope icon on your Windows desktop 2 PicoScope will detect your device and prepare to display a waveform The green Start button will be highlighted to show that PicoScope is ready adjacent to this will be the red Stop button 3 Try clicking your fingers over the microphone and the trace on the screen should react USB DrDAQ is now successfully installed and working EE o De dt Views Memwementi Took Help
33. jj v iy Tito BIA fit l You can add other channels to the oscilloscope screen by simply clicking the sensor you wish to view In this example we have added Temp While the trace is running put your finger on the temperature sensor and notice the rise in temperature Be fda yews Measurements Tools Heip nla eae ls EM oO bounalr an ribicope ir onmsir pet friis istai t1 elle 2 fel tse 3 ill a T eee dh 100 2 x 4200 so 2 mo o 100 O Copyright O 2011 Pico Technology Ltd All rights reserved usbdrdaq en Product information 2 6 3 Changing the oscilloscope timebase The timebase can be adjusted by selecting the drop down menu shown below Change the timebase to 50 ms div to see the change be Yevs Measurements Tools Hep a ata P G mmm fu x amp DO A bouns aB Scope loud fret 20 jay 500 imide imaj 2 mej y fee Edt Views Mesrwements Jools Hep CEOE somas 5 xs Eos Eq neo SII OURO A amp Goundi aB riscope le konmsi eri I ilana aai Eti Mirz oea f M 4 XE Ahhh f And RR AA AV dy HH thi HT HTT TTI il Ii HI HH I INI RIA TRI RIR SRI TAA ARININ Wy HU WW ap 1 i i vy 1 yyy y 4 ESERSE i vo i PUY VEY VU GY a ri so 1000 1500 x00 2500 x00 3500 000 4500 sos Ol
34. m Tel 44 0 1480 396 395 Fax 44 0 1480 396 296 www picotech com usbdrdag en 2 8 9 11 Copyright O 2011 Pico Technology Ltd All rights reserved
35. me of your container 2 Put the stand into the test container The stand should give you a clear platform above the level of the liquid Do not allow any standard solution to spill on to the top of your stand 3 Put the DD101 and DD100 sensors onto the stand If you are using a calibrated reference put this in too Connect the DD101 and DD100 sensors to USB DrDAQ Take your measurements Start the PicoLog Recorder software for USB DrDAQ Make sure USB DrDAQ is receiving readings from the sensors on Ext 1 or Ext 2 7 Seal the test container and close the insulated box if you are using a fan start the fan 8 Record the temperature and humidity inside the test container for at least one hour You must wait for the temperature to stabilise and the DD101 to provide correct readings This may take up to eight hours if you have used a large container 9 Check that the USB DrDAQ plots for temperature and humidity have been constant over the last few minutes of your measurements If you are using a calibrated reference take a reading of this now Take care to minimise the changes in the setup so that the reading does not change significantly 10 Save your results 11 Dispose of the solution as recommended by the supplier of the chemical Remember to take adequate precautions to protect your skin and eyes when disposing of the chemicals 12 Do the measurements again for the other standard solutions You should end up with a set of r
36. ng Managing Director Dec 2010 Pico Technology Limited is an internationally registered trade mark Registered in England and Wales No 2626181 usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 41 Index A Accuracy 12 C Calibration 1 3 35 Channels adding 7 Connections 13 D DD011 pH Electrode 15 DD100 Temperature Sensor 15 DD101 Humidity Sensor 19 DD103 Oxygen Sensor 24 Digital output 12 E ELO29 Reed Switch 18 G Grounding 1 3 H Humidity interface 19 L Laptops 1 3 LED 10 LEDr 11 32 Legal information 2 M Making your own sensors 27 Measuring pH 15 Meter view 9 O Overvoltage protection 1 3 12 Oxygen sensor 24 P pH electrode 15 PicoLog how to use 5 PicoScope how to use 6 PicoScope 6000 Series 3 Powering a sensor 28 R Reed switch 18 Repair 1 3 Resolution 12 RGB 10 11 32 S Safety warning 1 3 Sampling rate 12 Scaling 14 29 Scaling files 33 Sensors adding 15 Software updates 38 Specifications 12 Spectrum analyser 9 T Temperature sensor 15 Timebase changing 8 Trigger 9 Copyright O 2011 Pico Technology Ltd All rights reserved usbdrdaq en pico j Technology USB DrDAQ User s Guide 43 Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en Pico Technology James House Colmworth Business Park ST NEOTS Cambridgeshire PE19 8YP United Kingdo
37. nput channels menu item and click OK Select the Oxygen sensor from the list then click Edit Click on Options then Scaling From the drop down Scaling method menu select Table lookup From the look up table you completed above enter these values in the following format replace 19 9 with whichever value you read from the monitor view OBWNEF Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 26 Product information 0 0 195 9 210 09 Separate the values above with spaces 6 Close all of the dialogs by clicking OK in each one PicoLog s monitor view should now display 20 9 or very close for the oxygen content in air If so you ve successfully calibrated your USB DrDAQ oxygen sensor Storing the Oxygen Sensor Ensure that the storage temperature and humidity ranges in the specification are not exceeded The sensor is not designed for use in liquids and using it in this way will damage the sensor The sensor has a lifetime of 900 000 02 hrs in air at sea level the sensor will operate effectively for over 4 years this will decrease if the sensor is exposed to high oxygen concentrations for prolonged periods The lifetime of the sensor can be affected by exceeding the storage operating ranges and exposure to some gaseous chemicals in high concentrations Please avoid the following sodium hydroxide acetone MEK usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserve
38. or updates or replacements sent out on physical media Trademarks Pico Technology Limited PicoScope PicoLog and DrDAQ are trademarks of Pico Technology Limited registered in the United Kingdom and other countries Pico Technology acknowledges the following product names as trademarks of their respective owners Windows Excel Visual Basic LabVIEW Agilent VEE HP VEE Delphi usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 3 2 Product information 2 1 Welcome Thank you for buying a USB DrDAQ data logger from Pico Technology This low cost measuring device is supplied ready to use with all cables software and examples Features include Built in sensors for light sound level and waveforms and temperature Measure pH just plug in our standard pH electrode Scope input for voltage readings Sockets for external sensors Use USB DrDAQ to capture fast signals for example sound waveforms Digital output for control experiments Simply plug in to your PC and measure supplied with both Pico oscilloscope and PicoLog data logging software 2 2 Overview The USB DrDAQ features 14 channels comprising of sensors inputs and outputs These are covered in more detail in Specifications 1 These connections and sensors cover measurement of sound light voltage resistance pH levels and redox potential Ground Digital O Microphone Resistance LED USB connec
39. otes Light dependent resistor LDR can be used in conjunction with a fixed resistor to measure light level A suitable LDR sensor can be obtained from Maplin Electronics part number N53AY A resistor R of around 500k is suitable Example 2 Measuring 4 20 mA Current 4 20mA Notes 4 20 mA output is the industry standard for interfacing between a control centre data logger and a remote process such as a sensor For this reason 4 20 mA sensors are very common For relatively small currents a simple shunt resistor can be used to convert the current into voltage which the DrDAQ can then measure A suitable resistor R for the USB DrDAQ is 120 ohms This would give using Ohm s Law 0 4 volts at 4 mA 2 4 volts at 20 mA P Vxl Therefore gt 50 mW resistor required Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 32 Product information 2 10 4 Example 3 Measuring 10 volts Notes This is a simple circuit that uses a potential divider to reduce the voltage going into the USB DrDAQ by four R1 3k amp R2 1k The resistors are calculated using Ohm s Law V IR Auto Detect Auto detect resistor is placed between Ground Pin 2 and Signal Detect Pin 3 The value of the resistor should be selected from one of the following common values 1k0 2k2 3k3 5k6 7k5 10k It is necessary to have an auto detect R resistor so that the software can automatically sc
40. ound waveform ound level emperature nput 1 C 25 C 2 C 25 C ight nput p 16 7 million i N A colour pH sensor Input O to 14 pH 0 02 pH Sensor calibration Redox ORP 2 V 1012o 1 2 mV dependent Resistance _ Input OtoIMO 25000 10k0 5 Scope voltage Input 1 25 V 8 bit 2 5 V 5V 10 V with 100 kHz bandwidth O 2 2k0 0 3 3 V N A out 5 Vin PO SER Q gt z ml lt xo D e El D v 2 c jap e gt O Poi imi Eai nn q ie m O fam Ko out 5 Vin out 5 Vin nput mV External 2 As Ext 1 External 3 As Ext 1 Signal generator O to 20 kHz DC to 100 kHz 10 mV Oto 1 5 V running up to amplitude 2 MS s 1 5 V offset 2mV 39 N O 2 KQ 3 3 V N A N out 5 V in 2 N N J O a o F v g a gt ow Yo A A A A Yo m gt i ipie N olo na mim XT x nim w O Z cr kej Z or O gt O usbdrdaq en Copyright 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 13 2 7 3 Connections Channel Input Connection H redox ignal generator cope NC connector External sensor 1 3 CC68 4 pin connector Resistance input crew terminal Digital input output 1 4 crew terminal Connections and labels Ground Digital O Microphone Resistance LED USB connection Light sensor Ext 1 WWW DrDAQeCOM pico FARA ASS Temperature Technology senso
41. pico Technology USB DrDAQ Data Logger User s Guide Copyright O 2011 Pico Technology Ltd All rights reserved pico j Technology USB DrDAQ User s Guide l Contents MAMtrOd NEE ae AE E EEA ES EA Soin ta RE EEEE EA E E EEA A EAE EEES 1 EE aAA Te ETE EEEE EETA E EEEE E EOE E PE EEEE EET EAE EE ETTA 1 2 Safety warnings E EEE E PAEA AEE AE E SEE A E EA O E E 1 3 Legal Tae aan EAT ORD E A E A E E E EAE AA E OE EAE E E E A 2 2 Rroduet information sesso n E R E a r aa a a a san tr arena 3 UTWeleonie O nea ea area EAOa ENEE REEE EE E OEA ENE EEEE AU LED E Ea EEA AEA EAEE EEE OEA da nas andado 3 TOyerview Oen a ee e a ak vcs Rates ee Sus AE ea aaaea AAA nes Toda Eua desanima dida asteari a 3 3 Using PicoScope and PicoLog ERES E A A EE AEA E T A EE ARE E EAE 4 4 Installing the sOTtWARe s ses E E E E E E A E E E A E A E eduadd alega aca 4 5 Getting started with PicoLog DRA E E RAE E EA ED ADO ND ET 5 1 Using PicoLog for the first time ereceseststnstesseneesentssennennsnnsnannniasnnennsnnanuananasnnannaninian 5 6 Getting started with PicoScope c scecceseeeseeeseeeseetseesseeneeeeeeseesseessesesesneeseeeseesseesseesseeneeeeeessesseetsesneesneees 6 1 Using PicoScope for the first time sec eeeestsssnsseesnmansnnsennsnnsnsninnnasnunnnenuanuananannannnannaietn 6 2 Displaying channels saem 7 3 Changing the oscilloscope timebase eeeeeemeseeeeeesseseeeeeeemeemeeeeeeeeeeesesreeerrmeemmmeeeeeeeree
42. ppear s EN 32 of 32 DINAS Bei r Ee2 Ets F Ay Al Digital Out 1 Out vy Hh __ Se f Digital Out 2 Out High 1 Low Digital Out 3 Out v High Tr Low Ea I Digital Out 4 Out High Moving any of the 4 sliders to High will activate that digital connection however only connection 1 and 2 are able to output a PWM Pulse Width Modulation signal To do this click the digital out icon above the oscilloscope window and choose PWM in the drop down for either digital connection 1 or 2 E s Eq 32 of 32 DINI IIA btl Ee2 r Ee3 F Mg Al Digital Out 1 ims Ez Duty Cyde 50 a Digital Out 2 Out High ER im S Digital Out 3 Out High T Low Digital Out 4 Out High This allows adjustment of the PWM Period and Duty Cycle values Refer to Examples of digital in out usel3A for an example of PicoScope and the digital connections of USB DrDAQ Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 12 Product information 2 7 2 7 1 2 7 2 Specifications and connections General specifications Number of channels Maximum sampling rate 100 kHz streaming 1 MHz block mode nput overvoltage protection 30 V Digital output voltage Digital output impedance 2 2 kQ Output connector Input output and sensor specifications
43. r Ext 3 pH redox sensor Signal generator BNC Scope output BNC input BNC Any connection outside of its range can cause degradation to other signals being recorded To view the specifications for each channel refer to Input output and sensor specifications 125 External Inputs Each external input socket has four connections 1 input channel with 100k pull up to 2 5 V 2 Ground 3 Sensor type detect with 100k pull up to 2 5 V j Powerupto 100 mA 5V not protected limited Refer to Making your own sensors 15 for further information When using the External connections sampling above 1 kS s is not hardware supported for basic voltage resistance inputs Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 14 Product information 2 8 Channel scaling The following table gives details of the scaling for each channel Min Value Max Value Decimal 100 ope esistance Nin Q 10000 oD emperature ight xternal 1 epends on sensor xternal 2 epends on sensor epends on sensor igital 1 0 ff Low igital 1 0 ff Low igital 1 0 ff Low igital 1 0 ff Low m n High n High n High n High i g E El o Ea o o BS pH O Temperature EE EE p E RE E E Eos usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved EE EA Esse ESC o Es Es IS USB DrDAQ User s Guide 15 2 9 2
44. rvious to the standard solution Make sure that the material that your stand is made from is compatible with the test solutions you intend to use usbdrdag en Copyright O 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 21 Test container Your test container should be only just big enough to hold the DD101 and DD100 sensors the stand and a small quantity of standard solution the solution should fill approximately 5 of the volume of your container It will also have to be water tight with a seal that allows you to pass the leads for the sensors into the container Note The smaller your container the more quickly the humidity will stabilise You can reduce the time taken for the system to stabilise by forcing the air in the container to circulate This will require a fan that does not introduce heat into the container it must be driven by a shaft or magnetic coupling so that the motor is outside the container If you are going to compare the values measured with the DD101 and a calibrated reference your container will have to be large enough for the reference sensor too Make sure that the material that your container is made of is compatible with the chemicals you are going to use If the chemicals react in any way with the container the humidity reference will not be correct Standard Solutions The standard solutions may be harmful to your skin eyes or when swallowed Take all necessary precau
45. te Note The humidity that exists above all such solutions varies with temperature The standard solutions may be harmful to your skin eyes or when swallowed Take all necessary precautions to avoid contact when preparing and using the standard solutions Note For the highest accuracy you should compare the readings from you DD101 with the readings from a calibrated laboratory standard reference humidity gauge Calibration of the sensor involves Preparation of the calibration equipment Measurement of the standard saturated solutions Creation of calibration data for the USB DrDAQ software A check that the calibrated sensor is accurate Note You must measure at least two different standard solutions to provide two or more fixed points for calibration Equipment you will need USB DrDAQ with DD101 sensor Pico DD100 Temperature Sensor At least two Standard Solutions A label for the DD101 A test container An insulated box A stand for the DD101 Optional high accuracy calibrated reference laboratory standard humidity gauge Stand It is very important that the standard solution does not enter the case of the DD101 The solution may damage the electrical components of the sensor Therefore the DD101 needs to be suspended in the test container clear of the standard solution A small stand is the best way to hold the sensor above the solution The stand may be any object open framework that is impe
46. ter key 13 Enter all the pairs of measured and standard values that you have to build your table You should end up with two columns of values Note Your table must have at least two pairs of values 14 Click OK to close the dialogs Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 24 Product information 2 9 6 15 Click OK to close the Parameter Scaling dialog the Parameter Scaling dialog closes 16 Click OK to close the Parameter Options dialog the Parameter Options dialog closes 17 Click OK to close the Edit DrDAQ Measurements dialog the Edit DrDAQ Measurements dialog closes 18 Click OK to close the DrDAQ Measurements dialog the DrDAQ Measurements dialog closes This completes the entry of the calibration data Note You can remove the calibration data by opening the Parameter Scaling dialog and setting the drop down list to none If you want to completely delete the calibration scaling you can either edit and delete the entries in the Parameter Scaling dialog or use the New Settings command from the main menu If you use the New Settings command all scaling data will be lost Check the calibration To be sure that the calibration has been successful you must repeat the measurement stage of the procedure When the check measurements have been completed there should be very close agreement between the measured and standard values that is within 5 of the value If this is not the
47. tion Light sensor Ext 1 Ext 2 Temperature sensor Ext 3 pH redox sensor Signal generator BNC Scope output BNC input BNC The Software Development Kit for the USB DrDAQ is compatible with Microsoft Windows XP Vista and 7 32 bit and 64 bit editions Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en Product information 2 3 2 4 Using PicoScope and PicoLog PicoScope turns your PC into an oscilloscope spectrum analyser and meter PicoLog is a powerful flexible advanced data logging package for collecting analysing and displaying data The decision on whether to use PicoScope or PicoLog depends on the signals you wish to measure If you wish to collect fast signals such as sound waveforms then use PicoScope but if you want to collect data over a long period such as plotting battery discharge then use PicoLog Installing the software We have designed the PicoScope and PicoLog software to be as easy as possible to use even for newcomers to oscilloscopes and data loggers Once you have followed the simple steps listed below you will soon be on your way to becoming an expert pis 1 Install the software Load the CD ROM that is included with your scope device then click the Install Software link and follow the on screen instructions Plug in the USB DrDAQ device Windows will recognise it and prepare your computer to work with it Wait until Windows tells you that t
48. tions to avoid contact when preparing and using the standard solutions There are several chemicals that have been measured under laboratory conditions to find out what humidity they provide Whichever chemicals you choose make sure that the humidity they give is within the operating range of the DD101 sensor that is greater than 20 and less than 90 relative humidity You should use at least two standard solutions to give two fixed points for your calibration Standard reference books such as Kaye amp Laby Tables of Physical and Chemical Constants Longman give tables with the humidity of standard solutions For example Potassium chloride Magnesium nitrate Magnesium chloride Note The humidity produced by the standard solution depends on the temperature If the temperature changes from 20 to 21 Celsius this could give a change in relative humidity of as much as 3 for a nominal 50 value This change would be worse for higher values of relative humidity Insulated box Because the humidity produced by the standard solution depends on temperature you should use your test container inside an insulated box A domestic cool box without the cold blocks is suitable Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 22 Product information Preparation The standard solutions may be harmful to your skin eyes or when swallowed Take all necessary precautions to avoid contact when preparing
49. trove we x a usbdrdaq en Copyright 2011 Pico Technology Ltd All rights reserved USB DrDAQ User s Guide 2 6 4 2 6 5 Using the trigger The PicoScope trigger can be used to capture infrequent or one off events As an example click your fingers over the microphone a waveform is displayed but vanishes as soon as the display updates The correct way to capture such a signal is to use a trigger Stop PicoScope click on the Stop icon at the bottom left hand corner of the window or press the space bar and select a single trigger using the trigger options at the bottom of the screen Press the space bar to start PicoScope and click your fingers over the microphone The single trigger option means that PicoScope stops running when it has captured a signal MEZ IERTA T tot DORASTA NIJ i ee OO me sge vi ve Sore 4 Ov HJ ass im a Adding spectrum views So far we have looked at the oscilloscope functions PicoScope allows USB DrDAQ to be used as a spectrum analyser as well The buttons on the top left hand side control the oscilloscope and spectrum views Ryu il Oscilloscope view view signals against time Spectrum analyser view view amplitude against frequency Copyright 2011 Pico Technology Ltd All rights reserved usbdrdaq en 10 Product information 2 6 6 Adjusting the RGB LED Note When Enable LED Controlis active the LED will not flash when sampling The USB DrD
50. tsereemo 8 4 Using the trigger esmero mmmmemtetttees 9 5 Adding spectrum views custear rmmmmmmemeeeeeeestttaeremo 9 6 Adjusting the RGB LED essere reemeeeeeeeeesaereeararrmmemeemeeteeeettrrere 10 7 Controlling the digital outs eeeveseresenennernetrereeeteseeeetetesetretrettetrettetsetretretretsetretsetnrtretnserstnrtnrtet rte tt 11 7 Specifications and connections 1 General specifications 2 Input output and sensor specifications PE PEIA EIIE E PEIA JECA Ses Ponta bos Ene dias dude K EIIE EAA AIIE EREA do dese Seas astra 12 3 Connections PTP E pe PA O TEENETE IT OR AR IE O GR DOSE ADA TP RAP ESA RR RA EAN 1 3 8 Channel scaling eeeeeeeseseserseseseeseseseeseseeserenereesenersenesereenrnersenesereeseeersenererseneseeseserersesersesesereesesersesesereesreeeseses 14 O External Sensors E E E E E A E E E E E S E E 15 1 Overview gt ee 15 2 DD100 Temperature Sensor 15 3 DD011 pH Electrode 15 4 EL029 Reed Switch 18 5 DD101 Humidity Sensor wld 6 DD103 Oxygen Sensor uia 24 10 Making your own sensors s esesessesesseserersesessrseseseesesereenerereesesersenenenseneseneeneseneeseseesesenenseseseesesenenseseneeneseneene 27 1 Overview eres 1 27 2 Powering the sensor 28 3 Scaling te 29 4 Examples of digital out use 32 5 USB DrDAQ scaling files DDS 33 GCalibration sei pensadas o OO USAS ada apaga pago sagas cado 35 3 Software Updates a samasassadtesigedaso te caticuletuwh ca nsc
51. xt 1 Ext 2 or Ext 3 on USB DrDAQ Tips for use of DD101 Humidity Sensors The sensor responds to humidity changes more slowly in still air If you need to increase the response time then increase the air flow around the sensor For example swing the sensor gently on its lead or create a constant draft using a fan Do not blow into the sensor as your breath is very humid and will produce incorrect results Never allow the sensor to get wet for example do not take a cold sensor into a warm humid environment where condensation may form inside the sensor s case Copyright 2011 Pico Technology Ltd All rights reserved usbdrdag en 20 Product information Making accurate measurements The DD101 will give good readings of humidity and show trends well However if you need to make more accurate measurements you will have to calibrate the sensor The calibrated sensor could have an accuracy as good as 5 though this depends on how well the calibration procedure is carried out The output of the sensor may vary over time For this reason you should calibrate the sensor regularly at least once a year Basis of the calibration method Calibration relies on the general physical properties of saturated solutions The humidity above such solutions in closed containers is known quite accurately and is used to calibrate the sensors Chemical salts used for this purpose include potassium chloride magnesium chloride and magnesium nitra
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