pico Technology USB DrDAQ User manual

Copyright © 2013 Pico Technology Ltd. All rights reserved.
USB Dr.DAQ
User's Guide
usbdrdaq.en r4
Data Logger

IUSB DrDAQ User's Guide
Copyright © 2013 Pico Technology Ltd. All rights reserved. usbdrdaq.en r4
Contents
....................................................................................................................................11 Introduction
........................................................................................................................................1
1 Contact information
........................................................................................................................................1
2 Safety warnings
........................................................................................................................................2
3 Legal information
....................................................................................................................................32 Product information
........................................................................................................................................3
1 Welcome
........................................................................................................................................3
2 Overview
........................................................................................................................................4
3 Using PicoScope and PicoLog
........................................................................................................................................4
4 Installing the software
........................................................................................................................................4
5 Getting started with PicoLog
......................................................................................................................................................................4
1 Using PicoLog for the first time
........................................................................................................................................5
6 Getting started with PicoScope
......................................................................................................................................................................5
1 Using PicoScope for the first time
......................................................................................................................................................................6
2 Displaying channels
......................................................................................................................................................................7
3 Changing the oscilloscope timebase
......................................................................................................................................................................8
4 Using the trigger
......................................................................................................................................................................8
5 Adding spectrum views
......................................................................................................................................................................9
6 Adjusting the RGB LED
......................................................................................................................................................................10
7 Controlling the digital outputs
........................................................................................................................................11
7 Specifications and connections
......................................................................................................................................................................11
1 General specifications
......................................................................................................................................................................11
2 Input, output and sensor specifications
......................................................................................................................................................................12
3 Connections
........................................................................................................................................13
8 Channel scaling
........................................................................................................................................13
9 External sensors
......................................................................................................................................................................13
1 Overview
......................................................................................................................................................................13
2 DD100 Temperature Sensor
......................................................................................................................................................................14
3 DD011 pH Electrode
......................................................................................................................................................................16
4 PP066 Reed Switch
......................................................................................................................................................................17
5 DD101 Humidity Sensor
......................................................................................................................................................................22
6 DD103 Oxygen Sensor
........................................................................................................................................24
10 Making your own sensors
......................................................................................................................................................................24
1 Overview
......................................................................................................................................................................25
2 Powering the sensor
......................................................................................................................................................................26
3 Scaling
......................................................................................................................................................................29
4 Examples of digital output use
......................................................................................................................................................................30
5 USB DrDAQ scaling files (.DDS)
......................................................................................................................................................................32
6 Calibration
....................................................................................................................................343 Software updates
....................................................................................................................................354 Glossary
....................................................................................................................................365 Appendix A: Declaration of Conformity
....................................................................................................................................37
Index

USB DrDAQ User's Guide 1
Copyright © 2013 Pico Technology Ltd. All rights reserved. usbdrdaq.en r4
1 Introduction
1.1 Contact information
Address:
Pico Technology
James House
Colmworth Business Park
ST NEOTS
Cambridgeshire
PE19 8YP
United Kingdom
Tel: [phone]
Fax: [phone]
Web site:
www.picotech.com
1.2 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 minimize 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 connection (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 100 mA from the 5 V. The USB DrDAQ is
not limited or protected so overcurrents or short circuits could cause damage to the PC
USB port.
The unit has no user serviceable parts: repair or calibration of the unit requires
specialized test equipment and must be performed by Pico Technology Limited or their
authorized distributors.

Introduction2
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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 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 for 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, Delphi.

USB DrDAQ User's Guide 3
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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 PicoScope
(oscilloscope) and PicoLog (data logging) software
2.2 Overview
The USB DrDAQ features 16 channels, comprising sensors, inputs and outputs. These
are covered in more detail in Specifications . These connections and sensors cover
measurement of sound, light, voltage, resistance, pH levels, and redox potential.
The Software Development Kit for the USB DrDAQ is compatible with Microsoft
Windows XP (SP3), Windows Vista, Windows 7 and Windows 8 (32-bit and 64-bit
editions).
11

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2.3 Using PicoScope and PicoLog
PicoScope turns your PC into an oscilloscope, spectrum analyzer 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.
2.4 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.
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.
2. Plug in the USB DrDAQ device. Windows will recognise it and prepare
your computer to work with it. Wait until Windows tells you that the
device is ready to use.
2.5 Getting started with PicoLog
2.5.1 Using PicoLog for the first time
After installing the software, click the new PicoLog icon ( ) on your Windows
desktop. When PicoLog is first loaded the following screen will appear.
Under the Help menu, select Guided tour to be taken through the main functions in
PicoLog.
Refer to Examples of digital in/out use for an example of PicoLog and the digital
connections of USB DrDAQ. 29

USB DrDAQ User's Guide 5
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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 is 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.
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 ). At other times, you can leave a
message on our support forum or send us an email.
1

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Copyright © 2013 Pico Technology Ltd. All rights reserved.usbdrdaq.en r4
2.6.2 Displaying channels
To display channels in the oscilloscope window, move your mouse to the Channel
buttons which are located along the top of the oscilloscope screen.
Add a channel by clicking on the sensor you'd like to activate. In this example we
have activated the Light sensor; once activated the trace will appear, and the Light
button will be highlighted in blue.
You can add other channels to the oscilloscope screen by simply clicking on the sensor
that 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 corresponding rise
on the screen.

USB DrDAQ User's Guide 7
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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 change the display as follows:

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2.6.4 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 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.
2.6.5 Adding spectrum views
So far we have looked at the oscilloscope functions. PicoScope allows USB DrDAQ to
be used as a spectrum analyzer as well. The buttons on the top left-hand side control
the oscilloscope and spectrum views.
http://www.elso.sk/product.php?id_product=2744
- Oscilloscope view (view signals against time)
- Spectrum analyzer view (view amplitude against frequency)

USB DrDAQ User's Guide 9
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2.6.6 Adjusting the RGB LED
Note: When Enable LED Control is active, the LED will not flash when sampling.
The USB DrDAQ units include an RGB LED. The colour of this LED can be changed by
clicking the LED icon above the oscilloscope window. The following drop down will
appear:
Clicking Enable LED Control will show the numerical values for the LED to glow RED:
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.

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2.6.7 Controlling the digital outputs
The USB DrDAQ device includes several digital connections. To activate the digital
outputs, ensure your accessory is connected both to the GND of the USB DrDAQ and
the digital connection you wish to control. To operate the connections click the digital
output icon above the oscilloscope window. The following drop down will appear:
Moving any of the 4 sliders to High will activate that digital output. Only outputs 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 output 1 or 2.
This allows adjustment of the PWM Period and Duty Cycle values.
Refer to Examples of digital in/out use for an example of PicoScope and the digital
connections of USB DrDAQ. 29

USB DrDAQ User's Guide 11
Copyright © 2013 Pico Technology Ltd. All rights reserved. usbdrdaq.en r4
2.7 Specifications and connections
2.7.1 General specifications
Number of channels
16
Maximum sampling rate
100 kHz streaming, 1 MHz block mode
Input overvoltage protection
±30 V
Digital output voltage
3.3 V
Digital output impedance
2.2 kΩ
Output connector
USB 2.0
Dimensions
77 x 70 x 23 mm (including BNC connectors)
Weight
60 g (approx 2.1 oz)
Temperature
Operating: 0 to 70°C
Storage: -20 to +80°C
Humidity
Operating: 5 to 80 %RH
non condensing
Storage: 0 to 95 %RH non
condensing
2.7.2 Input, output and sensor specifications
Channel
Signal Type
Range
Resolution
Accuracy
Sound waveform
Input
±100
±0.2
Not calibrated
Sound level
Input
55 to 100 dBA
1 dBA
5 dBA
Temperature
Input
–10 to 70°C
0.1°C @25°C
2°C @ 25°C
Light
Input
0 to 100
0.1
Not calibrated
RGB LED
Output
16.7 million
colour
8 bit x 3
N/A
pH sensor
Redox/ORP
Input
0 to 14 pH
±2 V @ 1012Ω
0.02 pH
±1.2 mV
Sensor
calibration-
dependent
Resistance
Input
0 to 1 MΩ
250 Ω @ 10 kΩ
5%
Scope (voltage)
Input
± 1.25 V
± 2.5 V
± 5 V
± 10 V
with 100 kHz
bandwidth
8 bit
3%
Digital 1
I/O*
2.2 kΩ @ 3.3 V
out, 5 V in
N/A
N/A
Digital 2
I/O*
2.2 kΩ @ 3.3 V
out, 5 V in
N/A
N/A
Digital 3
I/O*
2.2 kΩ @ 3.3 V
out, 5 V in
N/A
N/A
Digital 4
I/O*
2.2 kΩ @ 3.3 V
out, 5 V in
N/A
N/A
External 1
Input
0 to 2.5 V
1 mV
1%
External 2
Input
As Ext. 1
As Ext. 1
As Ext. 1
External 3
Input
As Ext. 1
As Ext. 1
As Ext. 1
Function
generator/AWG
Output DAC
0 to 20 kHz
0 to 1.5 V
amplitude.
±1.5 V offset.
DC to 100 kHz
running up to
2 MS/s
2 mV
10 mV
*PicoScope supports digital output only, while PicoLog and the SDK support digital
input and output.

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Copyright © 2013 Pico Technology Ltd. All rights reserved.usbdrdaq.en r4
2.7.3 Connections
Channel
Input Connection
pH / redox
BNC connector
Function generator/AWG
BNC connector
Scope
BNC connector
External sensor 1-3
FCC68 4-pin connector
Resistance input
Screw terminal
Digital input/output 1-4
Screw terminal
Connections and labels
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 .
External Inputs
Each external input socket has four connections:
Pin
Function
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
4
Power up to 100 mA @ 5V (not protected/limited)
Refer to Making your own sensors for further information.
When used as basic voltage or resistance inputs, the External connections support
sampling rates up to 1 kS/s.
11
13

USB DrDAQ User's Guide 13
Copyright © 2013 Pico Technology Ltd. All rights reserved. usbdrdaq.en r4
2.8 Channel scaling
The following table gives details of the scaling for each channel.
Channel
number
Input
Min Value
Max Value
Decimal
Places
Units
1
Sound waveform
-100
100
1
-
2
Sound level
50
100
2
dBA
3
Scope
-10000
10000
0
mV
4
Resistance
0
1000
1
kΩ
5
pH
0
14
2
-
6
Temperature
0
100
1
°C
7
Light
0
100
1
-
8
External 1
Depends on sensor
-
-
9
External 2
Depends on sensor
-
-
10
External 3
Depends on sensor
-
-
11
Digital I/O
Off (Low)
On (High)
-
-
12
Digital I/O
Off (Low)
On (High)
13
Digital I/O
Off (Low)
On (High)
14
Digital I/O
Off (Low)
On (High)
2.9 External sensors
2.9.1 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 and 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
DD011 pH Electrode
PP066 Reed Switch
DD101 Humidity Sensor
DD103 Oxygen Sensor
2.9.2 DD100 Temperature Sensor
A 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)
0.1°C
Accuracy (at 25°C)
0.3°C
13
14
16
17
22

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Copyright © 2013 Pico Technology Ltd. All rights reserved.usbdrdaq.en r4
2.9.3 DD011 pH Electrode
Before using your electrode, remove the storage bottle.
Size
12 x 120 mm
Operating temperature
0 to 60 °C
Resolution
0.02 pH
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. 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, they will be destroyed in a few weeks. Trying to calibrate out
errors from a defective probe will not work and may further increase errors.
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 minimize 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 deionized 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 a 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 the reading to stabilize
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 it
is not, 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 at Pico
Technology.

USB DrDAQ User's Guide 15
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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,
two 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 between buffers.
1. Connect the pH electrode to USB DrDAQ and display the 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 stabilize (gently stirring helps).
3. Make a note of the reading and repeat the procedure for each of the buffer
solutions. Don't forget to wash the probe between buffers.
4. 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
4.06
7.00
7.07
10.01
9.92
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 these steps:
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.
3. Select pH and click Edit.
4. Click Options from the Edit measurement box.
5. Now click on Scaling and select Look up table from the menu box.
6. Enter the real measured pH value below Raw and the actual value in Scaled
(similar to the table in the previous section).
7. Click OK for all open boxes and verify the calibrated pH readings.
Storing pH electrodes
If KCl solution is not available then any pH 4 buffer solution will be suitable for storing
electrodes. KCl 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 deionized or distilled water!

Product information16
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2.9.4 PP066 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 unit.
Size
72 x 45 x 28 mm
Operating range
0 to 99%
Maximum response time
2 ms
The unit's 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 sensor 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 case. The label on the bottom of the unit indicates this position.
When a magnet is in place next to the unit the Reed Switch inside closes. This is
shown in PicoScope and PicoLog by a change from 99% (switch open) to 0% (switch
closed). This percentage is an indication of the proportion of the sampling period that
the switch is in the open state for.
You may use the unit 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 unit 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 unit on a firm flat surface, such as a table top, with the fixing screw
facing up and the connection socket towards you.
4. Remove the fixing screw.
5. Lift off the lid of the unit and put it to one side with the screw. 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
circuit board.
8. Loosen the screws in the terminal block. Do not remove them altogether.
9. Thread the two wires from the external switch through one of the holes in the
bottom of the unit.
10. If you do not wish to use either of the two holes in the bottom of the 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 electrical components.