pico Technology PicoLog Reference guide

AR346-1 © Copyright 2014 Pico Technology Ltd.
PicoLog
®
Self-Help Guide

PicoLog Self-Help Guide
AR346-1 © Copyright 2014 Pico Technology Ltd. 2/34
CONTENTS
1. Introduction....................................................................................................................................................2
2. Pico devices that can run under PicoLog.........................................................................................................3
3. Do not install PicoLog 5.23 over PicoLog 5.16...............................................................................................3
4. PicoLog does not recognise my device............................................................................................................3
5. Finding the PicoLog software version..............................................................................................................5
6. PicoLog crashes on start-up ............................................................................................................................5
7. What power settings should my PC have? ......................................................................................................7
8. When you start PicoLog, you get Player and not Recorder ............................................................................7
9. How do I record data from multiple devices?..................................................................................................8
10. Configure Windows to open PicoLog data and settings files with a double-click.......................................12
11. How to run multiple instances of PicoLog Recorder.................................................................................12
12. Remote data logging in PicoLog................................................................................................................13
13. PicoLog file size and recovery...................................................................................................................14
14. PicoLog frequency measurement..............................................................................................................15
15. Device-specific information.......................................................................................................................16
15.1 Device-specific – TC-08........................................................................................................................16
15.2 Device-specific – PicoLog 1012 and 1216............................................................................................20
15.3 Device-specific – ADC-20 and ADC-24................................................................................................26
15.4 Device-specific – PT-104 ......................................................................................................................29
15.5 Device-specific – PicoLog CM3 Current Data Logger...........................................................................29
15.6 Device-specific – USB DrDAQ .............................................................................................................30
15.7 Device-specific – PicoScope 2203, 2204, 2204A, 2205, 2205A .........................................................31
16. Related documents ...................................................................................................................................33
1. Introduction
This Self-Help Guide aims to help PicoLog Data Logger users troubleshoot and solve
common issues, in addition to providing device-specific setup information.
The Related Documents section contains links to electronic versions of User Guides that
can be accessed from our website.
Should you require any further information or assistance please contact our Technical
Support team:
Email: [e-mail]
Tel: [phone] (UK Headquarters)
[phone] (USA Headquarters)
Skype: pico_tech_support

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2. Pico devices that can run under PicoLog
The ONLY USB oscilloscopes that can run under PicoLog are:-
PicoScope 2104
PicoScope 2105
PicoScope 2202
PicoScope 2203
PicoScope 2204
PicoScope 2205
PicoScope 2204A
PicoScope 2205A
plus:
ANY of the older range of 3000 Series scopes that do NOT have an A, B or MSO
suffix.
Function Generator and AWG output are not supported in PicoLog.
ALL data loggers and ALL parallel port scopes will work under PicoLog on 32-bit
operating systems. Parallel port products and the USB ADC-11 are NOT supported on
64-bit operating systems.
NONE of the PicoScope 4000, 5000, 6000 or 9000 Series scopes work under PicoLog.
3. Do not install PicoLog 5.23 over PicoLog 5.16
It is best to uninstall R5.16.2 and then install R5.23.x so that “Auto-reconnect” will still
work.
4. PicoLog does not recognise my device
If the logger has worked before on this PC, it might be that the correct USB driver for
the logger has been corrupted. If this is a new installation, it is more likely that you
plugged the logger into the USB port before loading the PicoLog software in which case
Windows will try to load a generic driver which will not work. It will not be overwritten by
the correct driver until the wrong driver has been uninstalled.
Please try this: Plug in the logger and then go to Windows Device Manager (Windows XP:
Control Panel > System and then look in the Hardware tab; Windows Vista/7/8: Right-
click Computer, select Properties,then click Device Manager).
If there is an "Unknown USB device" anywhere in the list or, under either Pico
Technology Instruments or Universal Serial Bus Controllers, a Pico USB [xxxx] data
loggerwith a yellow warning triangle, click it once to highlight and then right-click to
bring up a list from which select Uninstall. Once that is done, unplug the logger and then
plug it back in again. The Windows New Hardware Found Wizard will run. Follow the on-
screen instructions and, if the wizard asks to connect to Windows Update, select No and
allow Windows to automatically detect and configure your logger.
Note to Windows XP users: During installation, if Windows displays a warning message
about Windows Logo testing, click Continue Anyway to complete the installation.

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When plugged in, the logger should show up in the Device Manager window again either
under a Pico Technology Instruments sub-item or the Universal Serial Bus controllers as
shown below:
Figure 1 - Windows Device Manager showing PicoLog 1000 and USB TC-08 Data Loggers
If the drivers have installed correctly, your PicoLog software should now work. You
should not need to reboot the PC.
If PicoLog still does not recognise your logger, you may have installed it incorrectly or for
the wrong device. Please rerun your PicoLog installation file, and select Remove when
you are asked to select Repair, Modify or Remove. After removal, rerun the installer to
install a fresh copy and when asked For which device do you wish to install, select the
primary device which you use with PicoLog. Also, for maximum compatibility, tick the
small box for Install for other devices. This will load all the other drivers for all other Pico
loggers and allow you to select them if you need to use them with PicoLog at a later
date. That should sort things out.
If there is still a problem with the settings of your PC that is preventing PicoLog from
being installed, you will need to send an installation log file to enable us to work out the
problem. Here is how to generate an Install.log file:-
Create a C:\Temp directory and copy the PicoLog_R5_23_0.exe download file into
it (or the latest version available). Make sure the logger is not plugged into the
PC. Now click the Windows Start button, select Run and in the command-line box
copy and paste the following:-
C:\Temp\PicoLog_R5_23_0.exe /v"/L Install.log"

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Click OK and PicoLog will start to install in the usual way. At the end, whether the
software has installed properly or not, there will be an Install.log file in the
C:\Temp directory. Please email that file to [e-mail] and we can
then see what has gone wrong with the installation.
5. Finding the PicoLog software version
Click Help and then About. The release number will then be displayed.
For Windows 98 and earlier, use version R5.16.2 of PicoLog.
For Windows XP and later, use the latest version of PicoLog available.
6. PicoLog crashes on start-up
If the software is crashing as soon as you start up it is probably because of a corrupted
setting in your plw.ini file. When you first run PicoLog, it creates a file called plw.ini and
tries to save it in its working directory:
•C:\Program Files\Pico Technology\Pico Full (32-bit operating system)
•C:\Program Files (x86)\Pico Technology\Pico Full (64-bit operating system)
PicoLog uses this file to hold information about the preferences you set when running the
program. Please see if locate the plw.ini file in the above folder and delete it.
If you still have problems starting PicoLog, it could be that there is a second copy of
plw.ini in a hidden directory. This will need to be deleted as well.
To access the Application Data/AppData folder and subfolders, the option to view hidden
folders within Windows must be enabled:
Windows XP:
•Go to C:\Documents and Settings\<User name> in Windows Explorer
•Click Tools > Folder Options…
Windows Vista/7:
•Go to C:\Users\<User Name> in Windows Explorer
•Click Organise and select Folder and search options

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Click the View tab, then under Hidden Files and Folders, select the tick box to Show
hidden files and folders, and click OK:
Windows 8:
•Click the View tab and ensure that the Hidden items option is ticked.
If you navigate to the following folder on your PC: -
Windows XP:-
•C:\Documents and Settings\<User name>\Local Settings\Application Data\Pico
Technology\
Windows Vista/7/8:-
•C:\Users\<User name>\AppData\Local\Pico Technology\
you will find one or more folders there with long numeric names. Look through each of
them for plw.ini and delete it.
Having done all the above, return to Explorer and select Do not show hidden files &
folders.

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7. What power settings should my PC have?
If, for any reason, the USB port shuts down because of Windows settings for power
saving, then the logger will freeze and the logged file will probably be corrupt. Please
ensure that all power-saving and screen-saver settings are turned off in Windows.
For instance, in Windows XP:-
•Start > Control Panel > Power Options > Turn off hard disks = Never
Windows Vista/7/8:
•Click Start > Control Panel > Hardware and Sound > Power Options and click Change
plan settings to edit the power settings. Set Put the computer to sleep to Never.
and:
•Device Manager > Universal Bus Controllers > USB Root Hub (multiple instances) >
Properties (right click) > Power management > untick “Allow the computer to turn off
this device to save power”.
8. When you start PicoLog, you get Player and not Recorder
If, when running PicoLog, you minimise the Recorder window, it will shrink to a small PL
logo in the bottom right of the toolbar:
Figure 2 - PicoLog icon in System Tray
After a short while, the icon may disappear. Expand the System Tray to locate the icon:
Figure 3 - PicoLog icon in expanded System Tray
When you wish to restore to the original window size, just double-click on that small PL
logo. The display will return to its previous state.
If, at any time Recorder is running, even when minimized, you double-click the main
PicoLog icon on the desktop, Player will start. (This will happen even if Recorder has
crashed, as it is often still running in the background. In that case, go to Windows Task
Manager, Processes, highlight plw32.exe and click End Process.)

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9. How do I record data from multiple devices?
Multiple identical or different loggers can be used at the same time on one PC running
under one instance of PicoLog. Here are example instructions how to use, for instance,
five TC-08 loggers at a time:-
1. Plug five TC-08s in via a powered USB hub. Start up PicoLog. Select File, then New
Settings. In the Recording dialog box, tick the box for Use multiple converters.
2. Continue to the Converters dialog:
and select Add.

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This will take you to the Converter Details box where you select TC-08 (USB). PicoLog
should find all the data loggers:
3. Click on the first one shown in the USB Devices box and click OK. You will be returned
to the Converters dialog where you click Add again. This will take you to the Converter
Details box where you select TC-08 (USB) for the second time.
4. When the second TC-08 is found, click OK. This will return you to the Converters
dialog where two USB TC-08 devices should be shown:

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5. Repeat 3 and 4 until all five USB TC-08 devices are found:
6. Click Parameters to set up each channel, for each TC-08, one at a time. All five
TC-08s will now behave as if they are one 40-channel data logger:
The data from all channels is saved to the data file and Recorder view can display all the
channels at once. Only 20 channels can be displayed at any one time in Graph view and
16 channels in Spreadsheet view. (Viewing more than 20/16 channels at a time would be
difficult to interpret.)

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You need to define multiple "Groups" of channels, no more than 20 (or 16) at a time
from the channels you have. You can then at any time call up these groups for viewing,
in quick succession. Please see page 37 of the PicoLog manual (issue 5) for how to set
up a group (please refer to the Related Documents section).
In the Recorder view you can choose which of the groups you display by selecting
Settings, Monitor and then, in the Select Parameters dialog, select the required group.
(You can leave it set to display all channels in the recorder main window.) When viewing
in Graph, select 20 or 16 channels at a time and when in Spreadsheet select just blocks
of 16.
You can make up additional groups by selecting the channels you require using the
Select Channels button and saving with a new group name. Use the different groups to
switch between the different channels to be viewed. Be aware that in Graph view
sometimes the new group can be not fully drawn until you zoom in or out or stretch the
window to force a redraw. For the groups to be saved with the data file, the groups must
be set-up before recording, not after.
Note: If you are looking to use different types of PicoLog data logger devices (e.g. a
USB TC-08 and ADC-20), please ensure that the tick box to Install for other devices is
selected in the Default Device Selection dialog during the PicoLog installation process:
Figure 4 - PicoLog Installer: Default Device Selection
If this option was not selected, it will be necessary to reinstall the software.

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10.Configure Windows to open PicoLog data and settings files with a double-click
You can save multiple PicoLog settings files and configure Windows to open them with a
double-click.
1. First enter your desired settings into PicoLog.
2. Next, go to File > Save as and change the file type to Settings files (*.pls). This
will save a .pls file on your computer.
3. Now right-click the .pls file in Windows Explorer and select Open with.
4. Ignore the default programs and navigate to the PicoLog installation folder, where
you will find the program plw32.exe:
a. For 32-bit operating systems, this will be
C:\Program Files\Pico Technology\Pico Full
b. For 64-bit operating systems, this will be
C:\Program Files (x86)\Pico Technology\Pico Full
5. Choose this as the new default program for .pls files.
6. Having done this, you can double-click any .pls file and instantly open PicoLog
with your saved settings.
For data files, undertake steps 3 to 5 (where plw32.exe will be the new default program
for .plw files.
11.How to run multiple instances of PicoLog Recorder
Normally, if the PicoLog application is loaded with an instance of PicoLog Recorder
already running, PicoLog Player will be loaded.
Section 3.13 (Run multiple recorders) in the PicoLog Data logging software User’s Guide
demonstrates how to create separate settings files for each device in the event that two
separate instances of PicoLog Recorder need to be loaded:
1. Attach one (or the first set) of the converters to the PC
2. Start PicoLog, select New Settings from the File menu, then follow the sequence
of dialogs to set up your converter(s)
3. Select Save as... from the File menu, navigate to the folder where you wish to
save the settings file, and from the Save as type: drop down box, select Settings
files (*.pls), then Save.
4. Disconnect the first converter and attach the second (or the second set) , then
repeat the steps above.
The User’s Guide then provides information on how to start the PicoLog Recorder
instances using the Windows command line interface. Alternatively, a batch file can be
created allowing a user to double-click the file and start the two instances of PicoLog
Recorder.

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Below is a sequence of steps to create such a batch file using settings files for two USB
TC-08 devices which have been saved in the PicoLog installation folder:
1. In a folder, right-click empty space and select New > Text Document
2. Open the text document and enter the following text, adapting it for the name
and location of your settings files:
cd "C:\Program Files\Pico Technology\Pico Full\"
START plw32.exe "C:\Program Files\Pico Technology\Pico Full\TC_08_1.pls"
TIMEOUT /T 10 /NOBREAK
START plw32.exe "C:\Program Files\Pico Technology\Pico Full\TC_08_2.pls"
Pause
NOTE: For 64-bit operating systems the path to the PicoLog installation directory
should read:
cd "C:\Program Files (x86)\Pico Technology\Pico Full\"
3. Save the text document and close it.
4. In the folder where the text file has been saved, right-click the file and select
Rename.
5. Enter a new name for the file, and change the file extension from .txt to .bat
a. If the file extension is not shown, open the Folder Options dialog as Section 3
in this document and uncheck the Hide extensions for known file types
option.
6. If a Rename dialog appears, click Yes to confirm that the file extension should be
changed.
7. Ensure that the required data logger devices are connected to the PC, then
double-click the batch file to start two instances of PicoLog recorder.
12.Remote data logging in PicoLog
It is possible to connect between two PCs on a network with the logger on one PC
(Server) and another PC acting as a Client:-
Taken from page 19 of the PicoLog User’s Guide (see Related Documents):
The PicoLog IP socket facility is used to take measurements on one or more computers
and record the data on another computer. The measurements are taken by PicoLog on
the Server. Another computer, the Client, requests the data via an IP network.
On the server:
1. Click Start
2. Select Run...
3. Type winipcfg.exe
4. Note the server name
On the client:
1. Open a DOS box
2. Type ping followed by the server name
3. The computer will display the time taken to send a message to the server and
receive a response
4. Check that it is working and note the time

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On the server:
1. Start PicoLog
2. From the File menu, select Preferences
3. Select IP Sockets
4. Check the Enable Server box
5. Click OK
6. Set up PicoLog to measure the channels that you require
On the client:
1. Start PicoLog
2. From the File menu, select Preferences
3. Select IP Sockets
4. Check the Enable Client box
5. Exit and restart PicoLog
6. Select New Settings
7. Enter recording details and click OK
8. Enter the sampling details and click OK
9. Select Socket in the Converter Type combo box
10. Click OK
11. Type the server name, e.g. fred
Note: Server names are case-sensitive! Fred is not the same as fred
12. Click Connect
13. The computer should now display the channels from the server
14. Click on one of the channels
15. If you want to change the name, type in the local name
16. Click OK
17. The channel you selected is marked with an X
18. Repeat for each of the channels
19. Click OK
20. The monitor window should now display the readings from the server
13.PicoLog file size and recovery
The largest file that is can be generated by PicoLog contains about one million samples
per channel (whatever the number of channels). If you wish to log for longer periods you
need to set PicoLog to Repeat Immediately at the end of a run. A new file will be started
with an auto-incremented file name. For ease of use, do not use the maximum file size,
but choose a convenient number of samples that gives a reasonable logging time per
file.
Once a file is saved to the hard drive it is safe from a PC crash or power loss. A long file
that is interrupted before saving can be corrupted and unreadable. We can sometimes
recover corrupted .plw files but only if you also have a good file available as well with
exactly the same settings to allow us to clone the headers across. Even a settings (.pls)
file with no actual data will work as well, as long as the channels, sample rate and
number of samples, etc. are identical.

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14.PicoLog frequency measurement
You can use PicoLog with the PicoLog 1000 Series (and certain oscilloscopes, see below)
to measure AC volts, dB and frequency, presenting the values as a graph (Real time
Continuous mode only). Our other data loggers are too slow to be useful for frequency
measurements.
•First, go to File > New Settings and select Real Time Continuous, then click OK.
•Select a sampling time of 1 second to take a reading once per second.
•Select the total number of samples or the total time of recording and click OK.
•Select PicoLog 1012/1216 and click OK.
•In PicoLog1216 measurements, click Add.
•In Edit PicoLog1216 Measurement, enter a name for the channel.
•Select Channel 1.
•For Measurement, select Frequency.
•Set the scan time to 100 000 µs, which will give you a frequency range of 20 Hz to
11.626 kHz.
•Using Options and then Scaling you can get PicoLog to display in RPM, not frequency
(click Help for instructions).
•Back in Edit PicoLog1216 Measurement, click OK.
•Back in PicoLog1216 measurements, click OK.
•Channel 1 should now be reading in Hz (or RPM if set).
To get frequency measurements for PicoLog at less than 1 second intervals (say 100 ms)
you need to modify your plw.ini file. This will be located in the following directory for
Windows XP:
C:\Documents and Settings\USER_LOGIN\Local Settings\Application Data\Pico
Technology\42f31349-afb8-471d-8a4d4fb7672be39b\
where USER_LOGIN is your user account. (You will need to enable viewing of "Hidden
Folders").
The equivalent folder in Windows Vista/7/8 is:-
C:\Users\<Your user name>\AppData\Local\Pico Technology42f31349-afb8-
471d-8a4d4fb7672be39b\
Open plw.ini in Notepad or a similar text editor and add the following line:-
QuickSampleMs=100
under the section labelled:-
[Preferences]

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Here is an example file:-
[Window]
Recorder=0,1,-1,-1,-1,-1,614,1168,126,523
[Converter]
Type=3200
Port=0
Selection=0
[Preferences]
AllowRerecord=Yes
AllowPause=Yes
QuickSampleMs=100
(This will allow sample rates down to 100 ms, for example.)
By default this is at 1000 ms, but you can change this to a lower value.
Save and exit, and next time you go into PicoLog recorder this will become active.
This is covered in the PicoLog User’s Guide on page 105 under QuicksampleMs (see
Related Documents). Also take note of frequency ranges. When you set up the channel
used for frequency, there is a section called Scan time. By changing the scan time you
can adjust the frequency range that you wish to measure. The scan time needs to be
three times the period of the frequency you want to measure.
15.Device-specific information
15.1 Device-specific – TC-08
Serial TC-08
To use the Serial TC-08 on a USB port you will need a USB to serial adapter, either ours
or another manufacturer's. That needs to be installed first, using the supplied software
driver, usually on a small CD. Once installed and working, you then need to go to
Windows Device Manager and look under Ports (COM and LPT) where there will be an
entry for a Serial on USB port with a COM port number in brackets next to it. (If the
COM port is greater than 4, force it into the range 1 to 4 by manually selecting the COM
port number.) Go to Windows Device Manager and select the hardware serial port you
wish to use. Right-click it and select Properties. Select Port Settings and then Advanced.
There will be a selection box for COM Port Number. Select a number less than 5 and click
OK. Windows might give a warning but ignore that. Use this new port number when
setting up the TC-08. The above instructions are for Windows XP but similar will apply
for other versions of the Windows operating system.
Plug your TC-08 into the USB adapter and run PicoLog. When asked for the COM port to
use, enter the COM port allocated in Device Manager. If you use a different USB port
next time, please be aware that the COM port number may change. If you restart a PC
with the USB to serial converter and TC-08 already connected, Windows will frequently
assume that a mouse is connected. This can happen with any device connected through
a USB converter.
Please try this: Unplug both devices from the PC and each other. Plug in the USB
converter, check it is recognised and to which COM port it is allocated. Finally, plug in
the TC-08. Use the COM port number found earlier to set up the TC-08 under PicoLog.

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You can use the current version of PicoLog (R5.23.0 at the moment). When installing,
still select Serial TC-08 as the device, not USB TC-08.
TC-08 sample rate
The TC-08 takes 100 ms per thermocouple to read temperature, and once per cycle
through all the active channels it must read the cold junction temperature as well, which
takes another 100 ms. Thus, if only one thermocouple is active, the full cycle takes
100 + 100 = 200 ms or 5 readings per second. If two channels are active, the full cycle
takes 2 x 100 + 100 = 300 ms or about three readings per channel per second.
If all 8 channels are in use, the cycle is 8 x 100 + 100 = 900 ms which means all 8
channels are read just quicker than once per second. When the cold junction is being
read (once per cycle) the LED is green. It is red when any of the thermocouple channels
are being read.
The above cycle is constant for the TC-08 and independent of the requested sample rate.
If samples are requested faster than 100 ms, consecutive readings will often be of the
same value until that channel has been updated, so readings are never older than the
sample time at worst. If the samples are requested at a slower rate, the readings will
always be the latest value which has been taken by the hardware no more than 200 ms
ago.
If Filtering is enabled, with say a filter factor of 3, then the display is not updated until 3
samples are available and then the average of those three samples is the value
displayed. It is generally best to set the sample rate to about the same as the cycle time
to get readings from all enabled channels. Adding a filter factor will smooth out
fluctuations in the readings at the expense of slower response to a fast temperature
change.
Using Scaling to adjust the calibration of each channel
Each channel can be adjusted to compensate for calibration errors.
It is easy to add a calibration factor to each channel using the Scaling option during
setup. The corrections can be saved to a settings (.pls) file, allowing the calibration data
to be reapplied to each channel on startup without the need to type everything again. A
greater number of points will give you a better calibration. You can use them to set up
Scaling to give you accurate readings directly to your data file and graphical display.
You just need to set the scaling for the channel in question. We will illustrate how to
scale Temperature for each channel.
Start PicoLog and set up your sample rates as required. When you get to setting up each
channel, click on Edit, then click on Options.
In the Parameter Options dialog box, click on Scaling to go to the next dialog.
In the Parameter scaling dialog box, select Table Lookup as the Scaling method.

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Assuming you just have data for the thermocouple for a two-point calibration (indicated
and true readings for two different temperatures), then type into the text box the two
pairs of numbers:-
aa bb
cc dd
where:
aa = the indicated reading at the first temperature
bb = the true reading at the first temperature
cc = the indicated reading at the second temperature
dd = the true reading at the second temperature
(taken from your calibration certificate for the thermocouple or your own measurements)
Note that there is one space between the two numbers on each line.
The actual table will look similar to this:-
9.5 10.1
94.5 95.0
This example tells the program to equate 9.5°C indicated reading to a true 10 °C and
94.5 °C indicated reading to a true 95 °C.
When the scaling is applied, the readings will be corrected.
Click OK to go back through the open boxes and temperature should now be scaled
correctly.
(Note:-Lookup tables have a limit of 14 lines. Above that, use a Scaling File.)
If you use a scaling file you must ensure that either:-
1. All parameter formatting is done on the parameter formatting page only and none in
the scaling file (just the equation or lookup table).
or
2. Parameter formatting is NOT ticked and all formatting is done in the scaling file only.
Duplication of parameter formatting will cause a crash!
When all channels are done, save a settings (.pls) file and next time, when you want to
reapply the same calibration to a logging session, just start PicoLog by double-clicking
the settings file instead of the PicoLog icon.
4–20 mA on the TC-08 using the Single-Channel Terminal Board
Here are some standard instructions for this sort of scaling of a 4–20 mA sensor to the
TC-08:-
The sensor will require a +24V supply. Feed the positive of the supply to the positive of
the sensor. Feed the negative of the sensor to the +5V/4-20mA input of the single

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channel terminal board. Connect the 0 V of the power supply to the Com terminal of the
single-channel terminal board. Set the switch of the single-channel terminal board to
4-20 mA.
The text below explains the setup process:-
The 4-20 mA will flow through a load resistor on the adapter board, generating between
9.5 mV (@ 4 mA) and 47.5 mV (20 mA). To convert these voltages into properly scaled
readings, you must use the Scaling option in PicoLog.
For example, if the sensor pressure is 0 psi when the current through the load resistor is
4 mA and 30 psi at 20 mA, you would set up a lookup table to equate 9.5 (mV) to 0 (psi)
and 47.5 (mV) to 30 (psi).
1. Start PicoLog and set-up your sample rates as required. When you get to setting up
channel 1 (Edit TC-08 channel), type psi as the Name and mV as the thermocouple.
2. Now click on Options.
3. In the Parameter options box, tick Use Parameter Formatting and set Units to psi,
Formatting to your own preference (three digits, one after the decimal point?), select 0
(min) and 30 (max) for the graph scaling and then click Scaling.
4. In the Parameter Scaling box, set Scaling method to Table look-up.
5. In the blank box, you can now enter two pairs of Raw and Scaled readings. In this
case the table looks like:-
9.5 0
47.5 30
(Note the space between the two numbers on each line.)
The 9.5 is derived from 4 (mA) times 240 (Ω) divided by 101 (attenuation in the single
channel board) = 9.5 mV.
The 47.5 is 20 (mA) times 240 (Ω) divided by 101 = 47.5 mV.
6. Click OK to go back through the open boxes and channel 1 should now be scaled from
0 to 30 psi.
Click on Help for an explanation of the process.
TC-08 channels all showing incorrect and variable readings
The 8 channels of the TC-08 are differential inputs. There are two pins per channel, each
with a 1 MΩ resistance to ground. The differential input resistance is thus 2 MΩ. The TC-
08 measures the difference in voltage between the two pins with a working range of
±70 mV maximum. For correct operation, both input voltages must stay in the range
±7.0 V with respect to ground (0 V). No damage will result if this common-mode voltage
is higher than ±7.0 V unless the voltage increases to above ±30 V. As long as all the
voltages stay within ±7.0 V of 0 V, the channels will read correctly.

PicoLog Self-Help Guide
AR346-1 © Copyright 2014 Pico Technology Ltd. 20/34
Incorrect and variable readings are usually caused by a thermocouple touching
something that is at a different potential to the TC-08 or PC earth. If this voltage is
greater than about ±7 V, the channel is pulled out of the common-mode range of the
TC-08. This causes all channels to read very incorrect values. You must ensure that the
metal object you are touching with the exposed end of the thermocouple is earthed
correctly and at the same potential as the PC earth. If that cannot be done, the
thermocouple must be electrically isolated from the metal surface. Failing that, for short-
term logging, you can use a laptop running on batteries, as that is not connected to
mains earth.
The overload can be on one channel, or between channels. The TC08 has an input range
of approx 70 mV. If more than 7 V difference occurs between any of the inputs to the
TC-08, incorrect readings will result. Additionally, if more than 7 V difference occurs
between the TC-08’s ground (also computer ground and usually mains earth) then errors
will occur. A typical example where this may occur is when a thermocouple is used to
measure the temperature of the motor on a machine tool. The casing of the motor,
although earthed, may be at a potential several volts different to that of the earth of the
computer.
Plug in the thermocouples one by one to locate which are causing the problems. If
possible, electrically isolate the thermocouple. If this is not possible, run a wire from the
metal outer shell of the TC-08 USB connector to a point near the thermocouple tip. This
will earth the area near the thermocouple tip and is often enough to pull the two grounds
close enough for normal operation.
Laptops running on mains adaptors can also cause problems. Some laptop power
supplies do not have an earth connection and produce large amounts of interference
which can be picked up by the sensitive TC-08. If you have problems when the laptop is
run off its mains adapter, but not on battery, try earthing the laptop. There is often a
screw on the back of the laptop that can be used for this purpose. Alternatively run a
wire from the TC-08 USB connector shell to mains earth. The USB TC-08 can be modified
to have a 4 mm ground socket if required. Contact Technical Support for further details:
[e-mail].
For links to the USB TC-08 Temperature Logger User’s Guide and the USB TC-08 Single
Channel Terminal Board please refer to the Related Documents section in this document.
15.2 Device-specific – PicoLog 1012 and 1216
Sampling at 1 ms in PicoLog with the PicoLog 1012 and 1216
If you find that you any only log at about 20 to 50 ms sampling rates, you are probably
running in "Real Time Continuous" mode.
This mode allows you to use multiple loggers at one time but the sample rate is slow (20
to 50 ms, dependant on PC speed). 1 ms cannot be obtained even if requested.
It does, however, allow you to also plot AC voltage, frequency and dB figures for signals
that are too fast for the logger to capture the actual waveform.