Configuring the LI-1400 Datalogger for Illuminance and Irradiance Studies

Transcription

1 Application Note Configuring the LI-1400 Datalogger for Illuminance and Irradiance Studies Introduction This document describes how to configure and deploy the LI-COR LI-1400 Datalogger (Figure 1) and LI-COR sensors used for datalogging illuminance and irradiance studies. Figure 1. LI-1400 Datalogger Figure 2. Terminal block plugged into the LI-1400 The LI channel data logger meter kit includes the following elements: x LI-1400 meter, a general-purpose 10-channel logger. x Software CD and user manual. x Up to five photometric (LI-250) or pyranometer (LI-200SA) sensors and mounting bases: These sensors produce very low current signal levels from 0±250 μamps, with a resolution as low as 7.6 picoamps that can be measured by the LI-1400 meter, but tend to elude many commonly available general-purpose loggers. x standard terminal block to connect an external power supply for extended logging periods without reliance on the internal batteries. The terminal block also provides convenient terminal post connection points for additional voltage and current sensors. Two BNC-type connectors are already attached to accept the two Li-Cor sensor types mentioned above. x Data cable to allow transmission of data from the LI-4000 (via RS232 serial communication) to a computer to extend the limited onboard data storage of the LI Most sensors have 10-foot cables, but cables as long as 100 feet are available. Notes: Details on the ten LI-1400 data input channels may aid in setup: x Five of the channels are current input channels that accept either of the sensors listed above (LI-150 or LI-200SA). x Three of these five channels (I1 I3) are case-mounted BNC connectors across the top of the meter. x The terminal block supplies two additional current input channels (I4 and I5) and has BNC connectors attached to two of its channel inputs (I4 and I5). It is plugged into the analog input/output (I/O) port of the LI-1400 (Figure 2). x The terminal block also provides inputs for four dedicated voltage channels and one pulse-counting channel. Please refer to the user manual for more detailed information on voltage and pulse counting channels and other LI-1400 features not discussed here. x The 4 AA internal batteries can provide 50 or more hours of operation, depending on the type and number of sensors attached. Alternately, a 12VDC power supply is attached to the terminal block between pin 24 (hi) and ground to allow longer unattended operation. 1 July 2014

2 Instructions Get Started 1. Connect up to 5 sensors to the logger using the BNC connection points (Figure 3). 2. Using the software CD provided, install the LI-1400 V1.1 application on the Windows-compatible computer being used (XP, Vista, or Windows 7). 3. Connect the logger to the computer with the data cable provided. The LI 1400 does not need to be ON in order to communicate with a computer. Figure 3. Sensors linked to the LI-1400 using BNC connectors 4. If the computer lacks an RS232 port, obtain an RS232-to-USB adapter and take these steps: o Follow the instructions provided with the adapter to install it and establish connectivity between the USB adapter and the computer. o If a USB adapter is installed identify the COM port it uses before establishing a connection with the logger (see step 5 below). See the Appendix to this document for more information on using the USB adapter. 5. To connect (Figure 4): o Start the software application. o Click the Remote/Connect menu to open the Connect dialog box. o In the COM port number field, enter a value and click Connect. The meter will take a moment to synchronize. On connection, a set of ellipses will temporarily appear in the lower right of the logger display, and the remaining menu items in the Remote menu will be active (no longer greyed-out). Figure 4. Connect dialog box 2 July 2014

3 Configure Channels Users will need to configure channels for each sensor used, following these instructions: Figure 5. Channel Setup dialog box 1. In the software application, select the desired channel (I1 for the first sensor, I2 for the second, etc.). The Channel Setup dialog box will appear on the right side of the logger display (Figure 5). 2. In the Sensor Type field, select Light. More options will appear (Figure 6). 3. In the Description field, add any description to be used in display viewing, if desired (e.g., sensor 1 ). 4. In the Channel Label field, enter a 3-character channel label that will appear with the logged data (e.g., L01) 5. In the Multiplier field, enter the MULT multiplier factor found on the sensor tag circled on Figure 7 (MULT: -9.66) Figure 6. More options in the Channel Setup dialog box 6. Referring again to figure 6, in the Average field, select any value desired. This field applies measurement display damping by averaging multiple samples before presenting the value. It is only functional when viewing real-time data in instantaneous mode and does not affect logged data values. 7. In the Logging Options field, click Choose. A new dialog box appears (Figure 8) which allows additional logging options. Select LR1 to apply logger routine #1 to the current channel for automated dated collection. (For more on log routines, see the Configure Log Routines section below.) 8. In the Calculation Type field, select the type desired. For example, selecting Mean as shown will average the values. If desired, select either of the Log Min-Max and Log Min-Max Times check-boxes and click OK. These options add columns to the log file containing minimum and maximum illuminance values and the times they occurred respectively. Figure 7. Sensor tag showing value for the Multiplier field Figure 8. Logging Options dialog box 3 July 2014

4 Configure Log Routines Log routines simplify setup by allowing users to assign a single set of specifications to multiple channels, following the instructions below. At least one log routine is needed to automate logging. Note that log routines only automate start and stop times; it is not possible to program the logger to start or stop logging on specific days or to log for a specific number of days. 1. In the LogRoutines area of the software application, select LR1. The Log Routines dialog box will appear on the right side of the logger display (Figure 9). 2. In the Start Time and Stop Time fields, enter values, if desired. To log for 24 continuous hours, for example, set these fields to the same value. (The logger interprets 00:00 as midnight.) Logging will commence at the time specified by the value entered, continue for 24 hours, and then stop. The logger will resume logging on each successive day between the start and stop times until memory is filled or, if in Overwrite mode, until the batteries are exhausted (see Launch the Logger section). 3. In the Sample Period and Log Period fields, set the desired values. The Sample Period refers to the frequency of data measurements; Log Period refers to how often those samples are integrated and recorded as a data record. 4. Create up to four additional log routines, as needed. Assign the log routines to one or more of the channels set up in the previous section. Figure 9. Log Routines area and dialog box Launch the Logger 1. From the menu, select the Remote menu. 2. Please note that turning logging ON does not erase existing data from memory. Nor does turning the meter off. To clear data: o Select Clear Database o Select All to delete all data or select UpTo to erase selected data o Click OK 3. Check Date and Time, if these were not checked previously (see the Get Started section above.) 4. In the Logging State field, select On to turn the logger on. 5. In the Overwrite Mode, select Yes to discard old data when the logger becomes full. Otherwise, logging stops when memory is full. 6. Select Send Setup to immediately begin transferring the setup parameters created to the logger. 7. The logger is now set up and logging. It can be disconnected from the computer for unattended logging by disconnecting the data cable and leaving the meter On to continue logging. 4 July 2014

5 Download Data If possible, download a sample of the data after 30 minutes to verify everything is working properly, following the instructions below. Downloading data will not interrupt logging or turn logging off. Logging is started and stopped inside the application from selecting On or Off in the Logging State field of the Remote menu (see Launch the Logger section above). It can also be controlled from the front panel keypad (see Appendix B for instructions). Figure 10. Sample of downloaded data 1. Reconnect the cable and open the software program. 2. Reconnect to the proper Com Port. (See Get Started section above.) 3. Click Remote/Receive Data/Download All. Enter a file name and save file when prompted. (The extract file will be in txt format, which can be read with Windows Notepad or opened in Excel for analysis and manipulation.) Notes on data downloads: x Downloaded data is always appended to any existing file found in a target folder of the same name as the file, even if the setup table has been changed and re-loaded. Provide a new file name to create a new data file with only the presently downloaded data. x The logging status after a period of unattended operation can be confirmed after data is downloaded by checking the last row of the downloaded data. If it begins with the number 100 and LOGGING OFF appears somewhere after the timestamp, the logger was not logging at the time of the data download. x A sample of downloaded data can be found in Figure 10. See the user manual for information on interpreting downloaded logger data. x To cross-check your data for reasonableness, compare it to data obtained using a hand-held illuminance meter. x Photometric data is recorded in klux and can be converted to footcandles by multiplying by 1000/10.76, or fcd/klux. Contact Information Please contact the Tool Lending Library staff at pectools@pge.com for further assistance. 5 July 2014

6 Appendix A: Identifying the COM Port Used by the USB Adapter The COM port number can be found in the Device Manager window (Figure 11). The navigation steps to the Device Manager window are operating system-dependent, and there is more than one path for each system. As an example, here is one way that Windows 7 users can access the Device Manager: 1. Click the Windows Start button at the lower left of the computer desktop. 2. Right-click Computer in the right-hand pane and select Properties at the bottom of the menu. This opens the system properties window. 3. Click Device Manager in the left pane. This opens the Device Manager window. 4. Find the node named Ports (COM & LPT) and click to expand the list of devices. The USB adapter being used should appear among the entries. Make a note the COM port associated with adapter (red arrow, Figure 11). That number will be required by any software application using the adapter for communication or data transfer. 5. If the USB adapter does not appear in the device manager window or there is an error flag next to it, there is a communication problem which must be resolved before proceeding further. Figure 11. Windows 7 Device Manager window Appendix B: Determining Logging Status From the Meter Keypad Please refer to figure 12. To turn logging on or off, or determine current logging status, perform the following steps: 1. Press Setup. 2. Press or to cycle through the various options until LOGGING is displayed. 3. Press Enter. SETUP LOGGING should be displayed. 4. Press or to turn logging on or off. 5. Press ESC to return to the top Setup menu. Figure 12. LiCor meter keypad Appendix C: Determining Battery Status From the Meter Keypad Please refer to figure 12. To check battery strength perform the following steps: 1. First, set up the battery data channel. Press Setup. 2. Press or until CHANNELS is displayed. 3. Press Enter. Then press nine times until VB= is displayed. 4. Press or until VB=BATTERY is displayed. 5. Now the battery strength can be viewed. Press View 6. Press or until VIEW NEW DATA is displayed. Press Enter. 7. Press or until VBI V is displayed where the 9 s are some decimal value indicating battery strength (e.g., V). 8. Fresh batteries are in the neighborhood of 6v or greater. The display will blink on and off when the battery voltage drops to 4.0V. The instrument will shut off when the battery voltage drops to 3.8V. Please note that the power supply voltage will be displayed if it is plugged in and connected to the meter. Temporarily unplug it to view battery level. 6 July 2014