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METER SC-1 Manual

Leaf porometer
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Summary of Contents for METER SC-1

  • Page 1 SC-1...

  • Page 2: Table Of Contents

    2.5 Downloading Data ..................11 2.6 Erasing Data .................... 14 3. System ....................... 16 3.1 Specifications ..................16 3.2 SC-1 Sensor Head ..................17 3.3 SC-1 Controller ..................19 3.3.1 Tabs ....................19 3.3.2 Modes .................... 23 3.4 Leaf Porometer Utility ................24 3.5 Theory ......................
  • Page 3 4.2 Maintenance .................... 41 4.2.1 Install Batteries ................41 4.2.2 Clean Sensor Head ................. 41 4.2.3 Replace Leaf Pads ................44 4.3 Troubleshooting ..................45 4.4 Customer Support..................48 4.5 Terms and Conditions ................49 Index ......................... 50...

  • Page 5: Introduction

    • White fluoropolymer agitation beads ® (McMaster-Carr PTFE balls, 1/8 in, part #9660K13) The SC-1 was shipped without batteries to preserve battery life and prevent damage to the instrument. Install four AA batteries in the SC-1 controller prior to use.

  • Page 6: Operation

    OPERATION 2. OPERATION Please read all instructions before operating the SC-1 Leaf Porometer to ensure it performs to its full potential. PRECAUTIONS METER instruments are built to the highest standards, but misuse or neglect may damage the device and possibly void the manufacturer’s warranty. Before using the SC-1, follow the recommended user instructions and arrange proper protections to safeguard the instrument from damage.
  • Page 7 12. After the last number is changed, press ENTER to return to the Configuration tab. 13. Use DOWN to highlight Units. 14. Press ENTER to scroll through the options. NOTE: The SC-1 default is millimoles per meters squared seconds (mmol/[m s].) The units can also be changed at any time on the Measurement tab.

  • Page 8: Taking A Measurement

    NOTE: Prolonged exposure (>2 min) to low RH conditions induces stomatal closure in most plant species. The SC-1 Auto mode measures stomatal conductance in 30 s, so the presence of the desiccated leaf clip should not cause stomatal closure unless multiple measurements are made in quick succession on the same location of the same leaf.

  • Page 9: Measurement Process

    METER recommends fresh desiccant be used for each day of measurement. NOTE: Early versions of the SC-1 sensor block do not have the desiccant chamber because the discontinued sensors in those models did not require it. However, current sensors require the use of the desiccant chamber for best results.
  • Page 10 Use the following steps to take a measurement: Turn the SC-1 controller on. Press MENU to navigate to the Configuration tab (Figure 6). Figure 6 Toggle between Auto and Manual modes Use the UP and DOWN arrows to navigate to Mode (Figure 6).
  • Page 11 Figure 7 Measurement tab before beginning a reading Press ENTER to begin a reading. The SC-1 will check the initial conductance and the absolute values of the RH sensors prior to beginning a reading. It is common to need to equilibrate the sensor due to one of these issues.
  • Page 12 The total shake down period should be approximately 50 s. If it takes longer than 75 s to equilibrate, the SC-1 may have a problem. Refer to Section 4.3. Once the measurement chamber has dried and equilibrated, the Measurement tab will display a prompt to insert the leaf (Figure 10).
  • Page 13 Complete readings of removed leaves within 2 min of removal (prior to stomatal closure) for an accurate measurement. NOTE: The SC-1 may not be appropriate for all needle types. Highly sclerified, angular needles will prevent a good seal over the diffusion path and the reading will be compromised.

  • Page 14: Saving Data

    OPERATION The SC-1 can measure the stomatal conductance beyond its recommended range of 0 to 500 mmol/(m s). Between 500 mmol/(m s) and 6,000 mmol/(m s), a ≈ symbol appears to the left of the reading. If the stomatal conductance reaches a value greater than or equal to 6,000 mmol/(m2s), an symbol appears in place of the measurement.

  • Page 15: Viewing Data

    Press ESC to return to the Data tab. 2.5 DOWNLOADING DATA METER recommends using the Leaf Porometer Utility (Section 3.4) to download data. This function transfers all saved measurement data on the SC-1 to a computer. Follow steps 1 through to download data.
  • Page 16 OPERATION Open Leaf Porometer Utility (Figure 18). Figure 18 Leaf Porometer Utility application Choose the appropriate communication port from the from the Use computer communication port dropdown on the main window (Figure 19). Figure 19 Leaf Porometer Utility main window Click Download. The Save Leaf Porometer Data window appears (Figure 20). Figure 20 Choose file name and location on the Save Leaf Porometer Data window Name the data file.
  • Page 17 SC-1 Select the location and the format of the file. The file can be saved as one of the following: Š Microsoft Excel® Workbook (*.xls) Š Text (tab delimited) (*.txt) Š CSV (comma delimited) (*.csv) Š Raw data (comma delimited) (*.txt) Click Save to download.

  • Page 18: Erasing Data

    • Filter Sensor RH (in percent RH) • Filter Sensor Temperature (in degrees Celsius or Fahrenheit) Data can also be downloaded through the SC-1 controller or a terminal program, if the Leaf Porometer Utility is not functioning properly. Contact Customer Support for more information.
  • Page 19 SC-1 To erase all stored data using the Leaf Porometer Utility (Section 3.4) : Connect the serial end of the USB-to-serial cable to the SC-1 controller. Connect the USB end of the cable to an available USB port on the computer.

  • Page 20: System

    SySTEM 3. SySTEM This section describes the SC-1 Leaf Porometer components and theory. 3.1 SPECIFICATIONS MEASUREMENT SPECIFICATIONS Stomatal Conductance Range 0 to 1,000 mmol/(m Resolution 0.1 mmol/(m ±10% of measurement from 0 to 500 mmol/(m Accuracy NOTE: The SC-1 can measure higher than 500 mmol/(m...

  • Page 21: Sensor Head

    COMPLIANCE Manufactured under ISO 9001:2015 EM ISO/IEC 17050:2010 (CE Mark) 3.2 SC-1 SENSOR HEAD This SC-1 sensor head gathers the measurements (vapor pressure, RH, etc.) that the SC-1 uses to calculate stomatal conductance in a leaf. Figure 25 shows the external components of the sensor head and Figure 26...
  • Page 22 Keep the strain relief screwed into the sensor head firmly. The SC-1 relies on a measurement of the RH gradient between the leaf evaporating surface and the desiccant chamber. The use of the desiccant chamber lowers the ambient RH to near 0%, thus ensuring a steep RH gradient between the leaf and desiccant chamber.

  • Page 23: Controller

    SC-1 Leaf Porometer Figure 27 SC-1 controller The SC-1 controller has six buttons. The POWER button turns the controller on and off. Pressing MENU switches between the Measurement, Data, and Configuration tabs. Pressing ENTER selects an option or begins a measurement. The two arrow keys (UP and DOWN) navigate within menus, and ESC backs out of menus or cancels actions.
  • Page 24 This menu is used to alter system settings (such as the current time, date, and operating mode), select the appropriate units for readings, and view information about the SC-1 (Figure 30). There is also a battery icon on the right, indicating remaining battery power.
  • Page 25 Mode can be in either Auto or Manual mode (Section 3.3.2). The mode must be set prior to beginning a measurement. • Units Data in the SC-1 can be displayed in three units: millimoles per meter squared seconds (mmol/[m s], the system default), meters squared seconds per mole (m s/mol), or seconds per meter (s/m).
  • Page 26 (Figure 33). Pressing ENTER during this screen will save a scan record that can be viewed or downloaded at a later time. Figure 33 Diagnostics screen • About The About screen displays SC-1 serial number and firmware version (Figure 34).

  • Page 27: Modes

    Auto mode makes an accurate stomatal conductance measurement in 30 s. To do this, the SC-1 takes the first 30 s of stomatal conductance data and applies a look-ahead algorithm to predict the final stomatal conductance reading if unlimited time were allowed for true steady state conditions to occur.

  • Page 28: Leaf Porometer Utility

    Open the USB drive named METER Group Inc. USA. Move the Leaf Porometer Utility application onto the computer’s hard drive. The four menus across the top of the screen change program and SC-1 settings. Below is a brief overview of the options each menu contains.
  • Page 29 • Command Retries: Set the number of times the computer should automatically try sending communications commands (up to 10). • Maximum Baud Rate: Set the maximum baud rate for talking to the SC-1. • Force Find All Communication Ports: Select checkbox to detect all communication ports on...
  • Page 30 Porometer Utility when connected to the internet. Updates can be manually searched for in the Help menu. • Automatic Clock Synchronization: Sets the SC-1 controller time to the computer time automatically, when connected. Figure 38 Applications tab in the Leaf Porometer Utility Preferences window...
  • Page 31 • Help…: Accesses the Leaf Porometer Utility help file that provides detailed information on how to use the program. • Send Feedback to Decagon: Provides the user with a way to submit feedback to METER. • Check for Utility Updates: Checks for application updates.
  • Page 32 SySTEM If upgrading to the latest firmware, verify the SC-1 is equipped with a desiccant chamber. Porometers that predate the desiccant chamber should not be updated beyond firmware version 1.33. Contact Customer Support for more specific information on upgrading the sensor head.

  • Page 33: Theory

    The SC-1 measures this rate by putting a leaf in series with two known conductance elements and comparing the RH measurements between them. The RH difference across the known conductance elements gives the water vapor flux.
  • Page 34 = 3.35 mm and d = 11.43 mm. The stomatal conductance ( ) is the variable the SC-1 ultimately measures. The derivation below shows how the variables above yield stomatal conductance. First, the vapor flux ( ) along the diffusion path will be determined using the RH...
  • Page 35 SC-1 Using (from Equation 2) and (from Equation 4) values, Equation 1 can be solved for the flux: ρ ! D ⎛ ⎞ vapor ⎡ ⎣ ) − h ⎤ ⎦ ⎜ ⎟ vapor ⎜ ⎟ ⎝ ⎠ Equation 9 Now that has been solved, the stomatal conductance ( ) can be determined.
  • Page 36 SySTEM ρ ! D vapor ⎡ ⎣ )(1− h ⎤ ⎦ d − d ) − h Equation 17 Therefore, is a function of the distances between RH sensors, temperature, and the two RH readings. When the conductance is small, the humidities are nearly the same, and the denominator of the denominator of Equation 18 goes to 0, causing problems.

  • Page 37: Service

    4.1 CALIBRATION For the SC-1 to make accurate readings of stomatal conductance, the two RH sensors in the sensor head must behave in a very repeatable manner. The sensors occasionally change characteristics over time. While the endpoint RH measurement may still be accurate, the response time of the sensors can change subtly which creates inaccurate conductance measurements.
  • Page 38 12. Make two or three consecutive measurements on the calibration plate. The resulting values should be within ±10% of the conductance value of the calibration plate, between 216 to 264 mmol/(m s). If the SC-1 does not return readings within this range, perfom a user-initiated calibration (step 6).

  • Page 39: Calibration Process

    SC-1. The calibration routine is the same as outlined in this section. NOTE: For instructions on how to upgrade the SC-1 firmware to the latest version, see Section 3.4. Each sensor head has a default 7-digit calibration number on the sensor head cable tag and on the calibration certificate.
  • Page 40 SERVICE Figure 44 Configuration tab Press ENTER to select Calibration. The Calibration screen will appear (Figure 45). Figure 45 Calibration screen options Press ENTER to select Calibrate... A warning screen will appear (Figure 46). Figure 46 Warning screen to wait for thermal equilibrium Press ENTER. 10.
  • Page 41 Figure 48 Stability Test screen The RH sensors must give similar RH readings to reach accurate stomatal conductance measurements. Before beginning a calibration, the SC-1 checks agreement between the two sensors in the sensor head. 11. Shake the leaf clip briskly in a vertical orientation to mix the air in the diffusion path and wait for the sensors to come to equilibrium (the indicator bar will move closer to the 0 line).
  • Page 42 NOTE: If the filter paper becomes too dry to adhere to the calibration plate, it will need to be wet again and the calibration procedure will need to be restarted. 18. Press ENTER on the SC-1 controller. The Attach Sensor Head screen will appear (Figure 50).
  • Page 43 SC-1 controller with the desiccant cap hanging off the edge. Proper orientation ensures the agitation bead sits on the Teflon filter and does not interfere with the water vapor diffusion from the leaf to the two sensors.
  • Page 44 22. The SC-1 will continue to take calibration measurements until three consecutive measurements are within 7.5% of each other. This ensures that the SC-1 measurements have stabilized. The calibration should end after performing three to five calibration measurements and will continue for a maximum of 10 measurements. If this does not happen, consult Section 4.3.

  • Page 45: Maintenance

    The SC-1 should be kept clean with full batteries to ensure proper working condition. To further extend the life of the SC-1, allow the sensor head to equilibrate to the ambient temperature before using and do not use it in rain or on leaves covered with dew or water droplets.
  • Page 46 SERVICE CLEANING MINOR CONTAMINATION Follow step 1 through step 22 to remove minor contamination of the diffusion path and other components (Figure 55). A short video of this procedure is at metergroup.com/environment/ articles/sc1-leaf-porometer-repair. Figure 55 can be used as a reference when performing the following steps. Leaf clip Screen Dry swab...
  • Page 47 SC-1 10. Use water and a soft cloth to clean contamination from the exterior surfaces of the aluminum block and rubber pads. 11. Allow the sensor head and screen to dry completely. 12. Place the bead retention screen over the diffusion path opening, with the concave side up.

  • Page 48: Replace Leaf Pads

    Leaf pads can fall off or become damaged. When the sensor head is cleaned, check the condition of the pads. They should make full contact with the leaf. A spare set of pads is included in the SC-1 kit. Contact Customer Support if more leaf pads are needed.

  • Page 49: Troubleshooting

    SC-1 4.3 TROUBLESHOOTING The SC-1 is a high-performance, low-maintenance instrument, designed to have few problems if used with care. Table 1 lists common problems and their solutions. If the problem is not listed or these solutions do not solve the issue, contact Customer Support.
  • Page 50 If this message continues to appear after two or three calibration attempts, contact Customer Support. The SC-1 is not in thermal equilibrium. Leave the sensor head at ambient conditions for 15 min and try again. The SC-1 will not calibrate, even after multiple Clean the diffusion path and replace the Teflon filter (Section 4.2.2).
  • Page 51 Ensure that desiccant is in place or replace with a fresh batch. This displays when the internal sensors have equilibrated at >10% RH. METER recommends to always use the desiccant chamber, but most importantly when ambient RH is > 30%. Ensure that desiccant...

  • Page 52: Customer Support

    SERVICE Table 1 Troubleshooting the SC-1 (continued) Problem Possible Solutions Replace the Teflon filter (Section 4.2.2). An air leak may have developed, allowing high RH air to leak into the measurement chamber. Equilibration shake • Check the integrity of the round rubber seal that caps the down period between measurement chamber.

  • Page 53: Terms And Conditions

    NOTE: For products purchased through a distributor, please contact the distributor directly for assistance. 4.5 TERMS AND CONDITIONS By using METER instruments and documentation, you agree to abide by the METER Group, Inc. USA Terms and Conditions. Please refer to metergroup.com/terms-conditions...

  • Page 54: Index

    INDEX INDEX sensor head. See  sensor head Teflon filter 1, 42, 46 averaging measurements 4 configuration date 2–3, 4, 21 time 2–3, 4, 21 battery units 2, 3, 25 icon 20 controller installation 1, 4, 41, 45 buttons 19 life 1, 17, 45 modes 23 type 17, 19 specifications 16...
  • Page 55 INDEX Leaf Porometer Utility Actions menu 27 screens communications settings 25 About 22 compatibility 24–27 Annotate 10 download data 11–14 Attach Sensor Head 38 Edit menu 24 Calibration 21, 36 erasing data 15 Calibration Complete 40 File menu 24 Configuration 20–23 Help menu 27 Contrast 22, 45 Preferences window 24–26...
  • Page 56 INDEX temperature 4, 17 terms and conditions 49 theory 29–33 troubleshooting 45–48 calibration 45, 46 date and time reset 45 firmware corrupt 46 firmware update 45 high initial conductance 7, 47 high RH 7–8, 48 sensor head failure 45 vapor flux 30–32 verification frequency 33, 41 procedure 33...
  • Page 57 10784-05 1.31.2020 METER Group, Inc. USA 2365 NE Hopkins Court Pullman, WA 99163 T: +1.509.332.2756 F: +1.509.332.5158 E: info@metergroup.com W: metergroup.com METER Group AG Mettlacher Straße 8, 81379 München T: +49 89 1266520 F: +49 89 12665220 E: info.europe@metergroup.com W: metergroup.de...

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