Yoyo Data Loggers. User Guide

Transcription

1 Yoyo Data Loggers User Guide

2 Copyright 2017 All rights reserved. The contents of this User Guide could be changed anytime without prior notice. Grant Instruments Ltd. disclaims liability for these changes. In using this software, Grant Instruments Ltd. takes no liability for any kind of loss or damage including all direct or indirect damages resulting from body injury, profit loss, operation interruptions, information or data loss. Further limitations are described in the license agreement, when installing the software. When installing the software, you agree to accept these terms. No part of this publication may be reproduced for any purpose or transmitted in any form or in any means either electronic or mechanic without written permission from Grant Instruments Ltd. Key Account Manager If you have any questions about installation or functionality of the software, please contact your local dealer or: Grant Instruments (Cambridge) Ltd Shepreth, Cambridgeshire UK SG8 6GB Tel: +44 (0) Fax: +44 (0) Trademarks MS-DOS, Windows XP/Win7/Win8/Win10 are registered trademarks of Microsoft Corporation. All other product names are trademarks or registered trademarks of the respective owners. Page 1

3 1 Content 1 Content Hardware Checklist Quickstart General information Installing batteries Software installation Main Software-Menu Preferences and general Setup Search for devices Logger Identification Logger Control Online- Meter Storing measurements while online metering Start/stop logger Active Start and Active Stop Download Data Logger Setup - General Logger Setup Sensor Slots Wiring external sensors Additional information on sensor connection Logger Setup Configuring Alarms Display logged data as a graph Display logged data as a table Exit Additional functions Batch command- automatic conversion ASCII Stream-functionality Troubleshooting Understanding LEDs Page 2

4 11 Password protection Important notes for measuring humidity Calibration/Maintenance Page 3

5 2 Hardware Checklist Included in delivery for all loggers are: - 2 nd Generation Data logger series yoyolog - Lithium battery SL550/S for 2YL-T14-4M/14E-4M, 2YL-RH24-4M/24E-4M - Lithium battery type LITH12 (SL-750/S) for all other models - USB cable - Software YoyoView for download at Further options include: - Calibration certificate - Carrying case - Wall holder, metal strip and seal - Connection cables YY-CS-4, YY-CU-4, YY-CI-4, YY-CP-4 for 2YL-T11-4M/T12-4M/M90-4M/M91-4M Page 4

6 3 Quickstart Receive your first readings in six easy steps: Install YoyoView Execute file \setup.exe Open the logger by unscrewing its rear cap. Insert the battery. Connect the USB cable to the respective ports of the logger and your PC. The Operating System will detect the device automatically. Wait for the notice that the device can be used. Start YoyoView. The program automatically recognizes the logger and displays a picture. Double click on the logger picture to select the logger. Right click on the logger and select Metermode. After a few seconds, you will be able to see online readings from your logger on the screen. Start logging in two additional steps Again Right Click on the logger picture and then click at Start Logger. Click on Start Logger now. The logger will start on the nearest minute with the preset interval of 10 seconds. The loggers blue LED will flash accordingly. Graph measured data in just another step Click at Download Data. Stored readings will be downloaded, saved as an ASCII file, and a graph is displayed. Page 5

7 4 General information The 2 nd Generation yoyo-series consists of a large variety of loggers. The full range of loggers is shown on page 7. Many of the yoyo-series of loggers have internal sensors such as humidity/temperature, barometric pressure and light. Other models have sensor slots to which external sensors may be connected. Some of these sensors are combined sensors (for example humidity and temperature). Such a combined sensor (for example YSRHT-120-2) can be connected to a single slot. The loggers have a memory capacity for 4,000,000 readings. It can be set to either stop-when-full or ring-buffer mode (continuous mode). The device offers an internal battery monitoring. YoyoView software will warn you if you need to replace the battery. In addition, the LED flashing periodically indicates the need for the battery to be replaced (see chapter 0, understanding LEDs for further information). The device can be controlled over the USB cable. It only takes a few clicks to select the relevant parameters. If you require information or technical support for 1 st Generation yoyo loggers, please contact Grant instruments support@grantinstruments.com. 1st Generation models are identified by model prefix YL e.g. YL-T10 Page 6

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9 All 2 nd Generation yoyo - Models at a Glance: Measured parameters and connectable external sensors Models Internal Sensors External Sensors YoYo 2nd generation Temperature Humidity Barometric Pressure Illuminance ELV/ Strain Gauge PT100/PT100 0/Thermistor/Thermocouple Voltage/Current/Pulse, Digital RH/T Probes, Water Detector, Soil Moisture Sensor Thermo-couple with mini ISA 2YL-T10-4M x 2YL-T10E-4M x 2YL-T11-4M x (1) 2YL-T12-4M x (1) 2YL-T14-4M x 2YL-T14E-4M x 2YL-T15-4M 2YL-T16-4M 2YL-RH20-4M x x 2YL-RH20E-4M x x 2YL-RH23-4M x x x 2YL-RH23E-4M x x x 2YL-RH24-4M x x 2YL-RH24E-4M 2YL-M36-4M x x x 2YL-M37-4M x x 2YL-M61-4M x 2YL-M62-4M x x x 2YL-M90-4M x x x (1,2) 2YL-M90E-4M x x x (1,2) 2YL-M91-4M x x x x x (1,2) 1 = connecting thermocouples requires cable type YY-CTC-4 3 = connecting voltage/currrent/pulse signals require special cable types YY-CU-4/YY-CI-4/YY-CP-4 A full list of specifications can be found on our website Page 8

10 4.1 Installing batteries The logger s power supply is provided by a 3.6V lithium battery. The following list shows which battery shall be used for your logger: - Lithium battery SL-550/S for 2YL-T14-4M/T14-E-4M and 2YL-RH24-4M/RH24-E-4M - Lithium battery type SL-750/S for all other models The logger offers internal battery monitoring. YoyoView will indicate when the battery will require replacing. In addition, the LED flashing periodically indicates the need for the battery to be replaced (see chapter 0, understanding LEDs for further information). To insert a battery into the datalogger, unscrew the back cover of the logger then insert the battery keeping the correct polarity. When the battery has been fitted the LED on the front of the logger will start flashing in red/green/blue after a few seconds to indicate it is operating. Battery life yoyo-logger Interval Battery life The battery life depends mainly on the logging interval selected. The table gives an overview for typical intervals. >1 min 4 years 10 sec 230 days 1 sec 25 days Some other factors reduce battery life- e.g., low temperatures decrease battery life. Downloading data or operation in MeterMode, Active start option enabled will also cause an increased energy consumption, which further decreases battery life. Page 9

11 5 Software installation The Software YoyoView can be downloaded on our website at: If you require a USB-stick containing the software you may order it separately. Hard-/Software Minimum-Configuration Recommended Configuration Computer: Intel Pentium, 1 GHz Intel Pentium III, 2 GHz Operating system: Windows XP/Win7/8/9/10 Windows 7/8/9/10 RAM: 512 MB 1 GB or more Monitor: Any windows-supported monitor Monitor with VGA- or higher resolution graphic Mouse: Any windows-supported mouse Any windows-supported mouse Port: 1 free USB-port 1 free USB-port Printer: Any windows-supported printer Any windows-supported printer After unzipping the file start the setup program Setup_YoyoView_ For- Windows.exe which will guide you through the installation progress.choose appropriate folder and after a few seconds the software has been installed. You will now be prompted to install the USB driver. Click at Install and wait until the driver has been installed. After the setup has been completed activate the box and click at Done to directly run YoyoView. NOTE: If YoyoView is not started automatically, please start it up manually. You will find it as usual in your Start section of the windows software as well as a shortcut on your desktop. Page 10

12 5.1 Main Software-Menu Within the main menu you will find most important functions as well as important information about the logger and the logger status. Hovering over the logging symbol will show logging interval. Page 11

13 5.2 Preferences and general Setup To set up preferences for the YoyoView Software, click on Preferences/Program or the Preferences icon. Click on Program to change the settings and paths within YoyoView. down- Set the default program used to view the loaded data Select Location where downloaded data is stored Click on Data to change export settings. Select Decimal places to automatic (default) to export data with as many decimal places as the sensor channels physically allows or select the required number of decimal places. Select the Column delimiter to TAB or Semicolon, as required. Page 12

14 5.3 Search for devices Locate the USB port of the logger, next to the battery, and plug in the USB cable supplied with the logger. Plug the other end of the USB cable into any USB port on the PC. Windows will automatically identify the logger using the USB-Express driver. In the YoyoView software a picture of your datalogger will appear. This may take up to 30 seconds. Normally a logger will be automatically detected when connected. If the logger is not automatically detected click on the icon or Devices/Search in order to scan the USB ports for new devices. Up to 6 dataloggers can be connected to the PC at any one time. A picture will appear for each logger allowing communication to anyone of them. If more than 6 loggers are connected, only 6 will be shown. NOTE: If the picture of the logger does not appear please check if the USB cable is properly connected and then refer to chapter Error! Reference source not found. for troubleshooting. Page 13

15 6 Logger Identification By moving the mouse pointer across a picture of a logger, a prompt will appear to click once or twice on that picture. By clicking once, further information will appear to identify the logger. A serial number, the Short ID, Date Code, Description as well as the manufacturers name will be displayed. If more than one logger is connected, double click on the particular logger to enable communication. This highlights the chosen logger. Now the logger has been selected further information is available. Click once on the logger s picture to show additional information about the logger model and status. Page 14

16 The full serial number, logger status, number of channels, firmware version, battery capacity, memory percentage used and the actual logger time will be displayed. Logger Status gives information about the status of the logger. If the status is sleeping, no readings are being taken and the logger is waiting to be set to log. If the status is logging the interval set will also be displayed. The battery voltage is an indication of the battery life remaining. It is recommended keeping track of the battery usage or simply use a new one if the status of the battery is unknown and data is important. Refer to table in chapter 4.1 to understand the impact of the interval on the battery life. The logger works with a lithium battery whose life isn t easy to predict. A brand new battery has a capacity of 3.6 V. A completely worn battery has less than 2.5V. The logger also predicts battery life which is indicated on the LEDs. Please refer to chapter Error! Reference source not found. to understand the meanings of the LEDs. Memory % shows the memory capacity used. Note, that stored readings are overwritten when the logger is set to start logging. Actual Time shows the loggers time. The logger automatically synchronizes its logger time with the PC time when it is starts logging. Page 15

17 7 Logger Control Once the logger has been selected you may also rightclick on it to control the logger. A logger control window is opened up and will show the following functions: Metermode, Sart/Stop Logger, Download Data and Logger Setup. 7.1 Online Meter In the Logger control window click on Metermode, to see current logger readings for channels that are set. Note that the screen shows channels in their numeric order. That means that first of all, all channels assigned to slot 1 will be displayed, then all channels assigned to slot 2 and so on. Please refer to chapter 0 for more information on Slot numbers and channel numbers. Note: The logger is mainly used for unattended long term logging, therefore Meter Mode is used to test the logger and verify that the sensors have been connected correctly and are providing the correct readings. When the logger is connected to a USB port it will self heat therefore the internal sensors may not be as accurate, the values may be up to 2 C higher than the actual values. Once the logger has been disconnected from the PC and moved to an external environment, the internal sensors of the logger may take up to a few hours to stabilize Storing measurements while online metering The online meter functionality will not only show the measured values on screen. It will also store all values as an ASCII-file in the Online -folder defined within preferences. Page 16

18 7.2 Start/stop logger Clicking on Start Logger in the logger control window will bring up the settings for logging. Note: that if the logger is already logging data, the Start Logger command will not be available. Instead the Stop Logger command will be displayed. In the Start DataLogging window there are the following settings: Logger Start condition, Logger Stop condition, Interval (unit/value) and a run description. The logger can be started immediately or at a specific date/time. When set to immediately the logger will start logging from the nearest full minute. To change the settings l click on the arrow button next to the default condition. To set the logger to start at a specific date/time, change the Start Logger at-condition to Select Date. Then browse the calender to change the Start date and time. Page 17

19 In the Start Datalogger window, the Stop condition for the logger can be set. If the Memory full option is selected the loggers will stop logging when the memory is full. If never (cont mode) option is selected the logger will start to overwrite the oldest readings when the memory is full. To set the interval rate of the readings, select the unit ; Hours, Minutes, Seconds or Hertz and define the Interval Value. Examples: to log every 10 Minutes, select Minutes at the Section Interval and enter 10 as the Interval Value. To log at 5 Hertz, select Hertz at the Section Interval and enter 5 as the Interval Value. Finally, a Description of up to 46 characters can be entered. This Description will be stored in the datafile to identify the readings when viewed later. When all settings have been entered as required, click on Start logger now. Once started a message will appear to confirm the logger has started logging successfully. Page 18

20 7.2.1 Active Start and Active Stop The active start functionality is unique to the 2 nd Generation Yoyo series by Grant Instruments. It allows you to conveniently setup and start the logger in your office before taking it out into the field to take measurements, which may be in a harsh environment with no computer nearby. To use this feature, click at Logger Setup, Setup device, Special Parameters. Enable ActiveStart option. After enabling the functionality, the logger knows that it then has to wait for a certain manual (shaking) procedure to start data logging. Remember, that you have to additionally start the logger. Active Start procedure 1. Start the logger (as described in chapter 7.2) and perform the following procedure (step 2 to 8) to actually start the logger to take readings. 2. Have the logger about 20 seconds laying untouched on steady ground. (This will calibrate the acceleration sensor in the logger.) 3. Locate the Multicolour-LED at the upper center of the logger. 4. Shake the logger once. (just one hard shake, holding the logger in your hand and pushing it downwards- make sure to hold it fast and not let it fall to the ground!) You will see the LED flicker in green 5. When the LED has gone off, shake the logger in the same way a second time. You will see the LED flash once in red colour! 6. When the LED has gone off, shake the logger in the same way a third time. You will see the LED flash twice in green colour! 7. When the LED has gone off, shake the logger in the same way a fourth time. You will see the LED flash three times in blue colour! 8. When the LED has gone off, shake the logger in the same way a fith time. You will see the LED flickers in red, green, blue to indicate that logging has now started successfully. Page 19

21 Active Stop procedure Stopping the logger works the same way as described for the active start. After shaking the logger five times it will indicate a successful logging stop by flickering in red colour. The active start and active stop is intentionally a multiple step process, to make sure the logger is not started or stopped accidently (for example during transportation). If it appears, that the shaking procedure does not end up in the LED flashing in multicolours (or red colours), the logger has not been started (or stopped) properly. In this case, start again from Step 1 as described above. Important: When the logger is started (either by active start or by normal start procedure) it will always overwrite the complete memory and data that hasn t been downloaded earlier is lost. Page 20

22 7.3 Download Data Clicking on Download Data will transfer all stored data to your PC. It will automatically store the files as a *.BIN-File and as a*.ascii file. The original *.BIN-File is a compressed datafile which can be archived using a minimum of hard disk space. The *.ASCII-File is used for the graphical analysis with the Graph- Tool of YoyoView (only YoyoView plus) and to import into third-party software. As soon as the data has been fully processed the GraphTool-Software will pop up. When purchasing the YoyoView Plus software there will be a serial number and two keys which will need to be entered here. If these have already been entered the analysis function will appear. (details about graphical analysis can be found in a separate manual for the GraphTool software package) The files are automatically stored in a folder defined by YoyoView. This can be found at C:\Users\Public\Public Documents\Graphtool In order to save space on your harddisk, you may also delete the ASCII files from time to time. As long as you keep the *.bin files which are typically a lot smaller, you may always recover the data by importing them with YoyoView. If you have a lot of *.bin-files to convert to ASCII, you may use the batch-command. See chapter 8 for additional information. Note: If the Plus-Edition of YoyoView has not been purchased, the software can be upgraded. Please contact your sales channel to purchase a YoyoView Plus license. Page 21

23 7.4 Logger Setup - General Click on Logger Setup, to define general settings for the logger, i.e. channel settings, alarm settings). This area is password-protected. Refer to chapter 11 for additional information. A picture of the logger is displayed so the inputs/slots can be identified. The battery capacity is displayed in the same picture. If the battery status is green the battery is still in a usable condition. If the battery is red, it should be replaced soon and only a short term logging period should be performed. Click on the General tab and then enter a logger name this can be used for later for identification. Click on More values, to set the calculated readings required. Select the calculated values as they are required to be returned. These will be stored in the same ASCII-file as the original data. Note: If the calculated values are not selected, the.bin file can be imported and the calculated values can be selected as appropriate. 7.5 Logger Setup Sensor Slots Page 22

24 Those loggers that have additional inputs for external signals or sensors have to be configured correctly to show the expected values and prevent damage. The input types that can be configured for different sensor/signals types are shown in the table in chapter Click on Logger Setup, Setup Device to configure the inputs. The actual configuration of the logger and the range are displayed. Click at the Sensor Slots tab. NOTE: This function is only available if the logger is actually not logging. Click on the symbol of the slot to be modified for example Slot2. Here the sensor type connected to Slot2 can be selected. If one of the standard sensors of the yoyo loggers is required then simply select the corresponding sensor type. If the sensor has any analogue output the sensor range can be scaled. For information about how to connect your (thirdparty) sensor click at WiringDiagramm. Furthermore you may rename the sensor in order to identify your readings in an easier way. Simply enter the required name at Slot rename. Page 23

25 YoyoView automatically assigns the minimum and maximum values of the sensor range. This can be altered if required. In order to set engineering units for the sensor, select Change to new Unit in the section Sensor- Range. Further settings can be entered. The above example shows the values for a sensor with a linear range of 0 50m/s = to 0 1V. In this example the following has been entered: Slot rename: Ductsensor8455 New Description: Velocity New Unit: m/s New Minimum: 0 New Maximum: 50 Once the correct settings have been entered for the sensor click on the OK button. As per the default, this new range will automatically be activated and logged when the logger is started. If the engineering units are no longer required they can be deselected at Logger Setup, General, More values, further information on this can be found in chapter Page 24

26 7.6 Wiring external sensors Terminal blocks The models 2YL-M36-4M and 2YL-M37-4M have terminal blocks which are used to connect external probes. The logger comes with two plugs ready to connect to the above loggers. When ordering sensors, simply use order code -0 for sensors with bare wires. Example: YS-EU for a temperature probe type EU with a PVC-lead with bare wires to connect to YL-M36-4M/YL-M37-4M. Please refer to the following chapters for connection of custom probe and sensors. Miniature sockets The models 2YL-T11-4M, 2YL-T12-4M, 2YL-M90-4M and 2YL-M91-4M have miniature sockets for wiring external sensors. All our standard probes for these loggers come with a miniature connector to plug onto the loggers sockets. Please make sure to select -4 for the correct connector. Example: YS-EU for a temperature probe type EU with a PVC-lead to connect to 2YL-T11-4M/T12-4M/M90-4M/M91-4M. If you need to connect custom probes and sensors you may use cable YY-CS-4, YY-CU-4, YY-CP-4 please refer to the following chapters for connection: Page 25

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28 7.6.1 Additional information on sensor connection Important: Connecting voltage/current/pulse signals higher than shown in the table before may damage the device! Pulse Count With both asynchronous and synchronous signals a pulse is counted when the switch is closed Strain gauge measurement With the 2YL-M37-4M logger you may measure two strain gauges. It is designed for full bridges at Ohms. Usually complete Strain gauge bridges are supplied calibrated. In the calibration certificate the bridge rated output C rated output C is converted as followed: Conversion of the bridge rated output C to C will be listed. With these specifications the bridge C = Example: C = 50kg / R = 120Ω C = = 0,24 50kg YoyoView plus has an integrated formula editor, which allows you to enter a formula as described above to calculate Forces/tensions from the mv reading Current measurement (max 24 ma) 2YL-T11-4M/T12-4M/M90-4M/M91-4M When measuring current signals with one of the above models you have to use the YY- CI-4 cable. The YY-CI-4 has a 10 Ohm shunt resistor built in. 2YL-M36-4M/M37-4M The 2YL-M36-4M/M37-4M have an internal shunt so signals of up to 24mA may be connected directly using standard cables. Page 27

29 The transmitter will be required to be powered externally. Correct Incorrect Always connect the data logger to the lowest potential of your current loop. Meter the low-side current and do not meter the high-side current! Page 28

30 7.7 Logger Setup Configuring Alarms Yoyo loggers have integrated alarm functionality. An LED will start to flash if thresholds are exceeded. Click on Alarm, to display the alarm settings. Then click on the symbol of the channel in order to change the settings. Select from the following Alarm Modes: One alarm range: Sensor Max Min No Alarm Alarm No Alarm There is one alarm range for the selected channel. If the sensor value is higher than the (Alarm threshold1 ± Hysteresis) and lower than (Alarm threashold2 ± Hysteresis) the logger will start to alarm.. Two alarm ranges: Sensor Max Min Alarm No Alarm Alarm There are two alarm ranges for the selected channel. If the sensor value is higher than the (Alarm threshold1 ± Hysteresis) and lower than (Alarm threashold2 ± Hysteresis) there is no Alarm. Otherwise the logger will start to alarm.. Now set the values for Threshold 1 and Threshold 2 and define the Hysteresis. Page 29

31 7.8 Display logged data as a graph Click here or go to Data/Graph to display readings in graph. You will be prompted to select a file for graphing. YoyoView automatically searches is its predefined folder: C:\Users\Public\Public Documents\Graphtool. As soon as the data has been fully processed the GraphTool-Software will pop up. If you have purchased the YoyoView light/enhanced software you have received a serial number and two keys which you need to enter here. If these have been entered you may now analyse the data. If you haven t purchased the light or enhanced-edition of YoyoView, you may upgrade the software and add new options lateron. Contact you sales partner to obtain YoyoView light/enhanced. 7.9 Display logged data as a table Click here or go to Data/Table to display data as a table. You will be prompted to select a file for graphing. YoyoView automatically opens the file and searches its predefined folder, which both has been set up in the preferences section Exit Click here or go to File/Exit to exit the application. Page 30

32 8 Additional functions 8.1 Batch command- automatic conversion With YoyoView installed on your computer you may also automatically convert many *.bin files without any interaction. You may start YoyoViews conversion procedure via input command. Syntax: YoyoView.exe [SPACE] /convert [SPACE] complete path to *.bin All converted files (*.ASC) will be stored in the same folder, where the original data has been found. The whole process is performed in the background and there is no process indicator. When a 0 is confirmed back the conversion has been completed successfully. 8.2 ASCII Stream-functionality The ASCII-stream function allows for getting logger measurements into your own hardware. It allows remote-control via Serial Interface between Logger and Host to get online measurements in a simple way. Use software: ASCIIStreamTool.exe to switch between YoyoView-mode and ASCIIStream-mode. This tool may found in install folder of YoyoView. Additional information on ASCII-Stream-Mode can be found in an Application Note ASCII Stream Documentation.pdf which can be found at help/manuals Page 31

33 9 Troubleshooting Typical error messages that may occur during operation are listed below. Try to solve the problem with the following help list before contacting your distributor. A) No logger is displayed First, check if the logger cable is correctly connected to the USB Port and to the logger. Secondly, uninstall the software and re-install the complete package (software/usb-driver). Administration rights are required during the installation process. If the problem still exists there may be a fault with the logger. B) Unknown Logger is displayed The software being used may be an old version, which doesn t recognize the new hardware. Check with the local dealer for any upgrades. C) Cannot contact logger If the error message continues to show after checking that the loggers is connected correctly and appears in the YoyoView software. This could be due to the logger having a flat or missing battery. Replace the battery and verify initial function test as follows: After having inserted the battery the LED on logger front should flash in all three colours (LED chaser). This shows the logger is operating. Now, try contacting the logger. If problem still exists there may be a problem with the logger hardware, contact the local dealer. D) Logger stops taking readings after a period logging. Please check the logger setup for any settings selected for a stop date/time, change the setup if necessary. Otherwise this could be due to a flat battery. Check battery voltage in YoyoView (see chapter 4.1) and possibly replace battery. E) Humidity/Temperature readings continuously show -40 C/+120 C. Humidity/Temperature-Sensor is faulty or the cable has been damaged. F) Other sensors continuously show their Max/Min: Sensor or sensor cable could be damaged. Page 32

34 10 Understanding LEDs Logger Status Red LED Blue LED Green LED Logs at interval - Flashes according - to log interval Monitors alarm conditions - - Flashes every 8 secs Alarm active Long Flash for second every 8 seconds Alarm occured but is Short Flash every - - not active anymore 8 seconds Battery empty Intense flickering - - for 0.5 seconds every 15 seconds System check OK after LED chaser battery change Page 33

35 11 Password protection Some of the settings in the datalogger may not be changed without entering a password. As default, the logger comes with the password Please keep your password in a safe place! If you have lost your password, the data can only be recovered by sending the *.bin file to the manufacturer of the instrument. As this is not free of charge, please make sure to protect your password, accordingly. Page 34

36 12 Important notes for measuring humidity The Yoyo humidity/temperature probes are a precise, reliable humidity sensor element which has a good long-term stability. The capacitive sensor allows for humidity measurement in many applications and will give stable readings in clean environments for several years. Depending on the environmental conditions the sensor can become contaminated by for example: dust, chemicals and dirty water which will reduce the active life. There are further limitations, the sensor may be used in an operating range of 0-100% RH this operating range is reduced at as the operating temperature increases. See the graph below. This is due to the fact that quite an aggressive environment is developed when measuring high humidity and high temperature at the same time: Humidity Operating conditions Normal/Range Max. Range Temperature The sensor should not be damaged when condensation occurs occasionally. If condensation does occur, dry out the sensor in order to return to the correct measurements, except the sensor polymer is contaminated with substances (see above). If condensation occurs regularly or for a long period of time, the sensor life is reduced. If the sensor is even saturated it may give incorrect readings in the range of 0-100% RH (sometimes even negative readings), but will recover when water droplets have evaporated. To ensure high quality readings we therefore recommend that probes/loggers are verified and calibrated on an annual basis. Page 35

37 13 Calibration/Maintenance Yoyo loggers are factory calibrated using dedicated equipment which is calibrated according to ISO/IEC17025, by comparison against natural standards, natural physical constraints or by ratio type measurements, using self-calibration techniques. To ensure that measurements are reliable and correct we recommend calibrating the logger s sensors within 12 months of purchase The logger itself only requires a minimum of maintenance. Verify O-Rings are clean and non-damaged and remove any dirt.. Page 36

38 Grant Instruments (Cambridge) Ltd Shepreth Cambridgeshire SG8 6GB UK Tel: +44 (0) Fax: +44 (0) /DMN P87/Sept2017