Software tour

The pCO2 application opens to a System Initialization screen, which presents options to connect to devices, configure measurements, view data, and view the system status.

System Init.

System initialization presents the initial configuration options. The component selectors allow you to select the devices that are contributing data to the measurement. Options may include the GPS receiver, pH sensor, dissolved oxygen sensor, chlorophyll sensor, and weather station.

  • Aanderaa Dissolved Oxygen, Cyclops Chlorophyll, and Weather Station should be set to In Use.
  • GPS and Honeywell Durafet - pH are no longer supported and should be Not In Use.

Device Config.

Click Device Config. for the settings of CO2 analyzer model, GPS input, overflow alarm criteria, user-calibrations of the chlorophyll sensor, and the time and frequency of the peristaltic pump.

LI-COR Model: Select LI-7815 from the upper menu and enter the hostname (on the serial number label). Other gas analyzers in the list are not supported at this time. Leave the second option set to Not in Use.

GPS Input from the Airmar Weather Station is used. Other GPS sources are not supported.

Overflow Alarm: There are two sets of parameters for the overflow alarm, while the basic set is inaccessible to the users. The basic parameters dictate when the overflow alarm is registered in the program. The advanced parameters in this tab dictate when the program aborts the measurements.

The basic parameters are set to stop the water intake if the water level is too high for 4 seconds continuously. Then if the overflow attempts button is set to 1X in the device configuration tab, it stops the water flow by engaging the shut-off valve AND aborts the measurements. However, if the overflow attempts button is set to 2X, it only engages the shut-off valve and ignores the overflow for 6 seconds before it checks the status. The measurements continue normally during this 6-second delay. If the water level is still too high after water has been allowed to drain for 6 seconds, the program aborts the measurements, and the shut-off valve is left engaged. The maximum delay allowed is 20 seconds.

Regardless of the overflow attempts, an audible alarm is always played as long as the water level is high enough to trigger the physical alarm inside the equilibrator.

Chlorophyll Sensor: Input the coefficients for the relationship between voltage readings and fluorescence for all three gains. See Calibrating the chlorophyll sensor for user-calibration information.

Peristaltic Pump: Enter the time between runs (Interval (mins)) and the duration of the pumps to run (Pump ON (mins)). The default settings call for the pump to run for 1 minute every 30 minutes. They are always turned on after the Start Sample button is clicked. The 30-minute countdown starts at this point.

Click Connect to establish communication between the selected device and the program. The software will display the status of each device.

Exp. Config

Exp. Config presents options for a measurement, including details about the project (PROJECT INFO), gas standards, chlorophyll gain setting and the timing and sequence. The timing and sequence is described in The measurement sequence. Operating information is in Measuring pCO2 in water.

Manual DAQ

The portion of the interface under Manual DAQ is to manually control pumps, gas sources, and other parameters of the system. This tab is useful for troubleshooting or testing that components respond as expected. You can manually control the system and collect data using these controls, but this is only recommended if, for some reason, the automatic procedure is not available. In this section, we describe the controls in the Manual DAQ page.

  • PUMP CONTROL: Each pump can be turned on or off by clicking the button. The status is displayed on the button.

    • Air pump: Pump for the ambient air intake.

    • Vacuum pump: Draws air through the nafion drying system.

    • Peristaltic pump: Pumps that evacuate water from the condenser unit.

    • Sample pump: When turned on, automatically switches the SOURCE SELECTION to sample.

    • Choose how to exhaust the air: Open to Air or Recycle to Equilibrator.

  • OXYGEN OPT. SALINITY: You can let the software read the salinity from the sensor during automatic measurements or you can enter the salinity value in the box during manual measurements. If the button displays Manual, you should enter the salinity value in the text box. This setting applies only to manual data acquisition. If it displays From SBE 45, the system will take the reading from the SBE 45. When measuring automatically, the system always takes the salinity readings from SBE 45.

  • SOURCE SELECTION: The menu presents the following options:

    • Air/Port 1: Air from the ambient air intake will be directed through the gas analyzer.

    • Seawater/Port 2: Gas from the equilibrator headspace will be directed through the gas analyzer.

    • Calibration standard 1/Port 3: Gas from CO2 standard 1 is controlled with port 3 on the internal valve.

    • Calibration standard 2/Port 4: Gas from CO2 standard 2 is controlled with port 4 on the internal valve.

    • Calibration standard 3/Port 5: Gas from CO2 standard 3 is controlled with port 5 on the internal valve.

    • Calibration standard 4/Port 6: Gas from CO2 standard 4 is controlled with port 6 on the internal valve.

    • Calibration standard 5/Port 7: Gas from CO2 standard 5 is controlled with port 7 on the internal valve.

  • FLOW RATE SETTING: This setting applies to the internal mass flow controller. The minimum gas flow rate is 100 mL/min. You must click outside the box to apply this setting after changing it.

  • DEVICE READING: The menu presents devices available to read. Select a device to trigger a measurement. Click READ to trigger another measurement.

  • MEASUREMENT SETTING: The menu presents Single measurement or Continuous measurement (series) with a Time Interval setting. When configured, the Start Manual DAQ and Stop Manual DAQ buttons become active.

Start Manual DAQ and Stop Manual DAQ

If you click Start Manual DAQ, results are displayed in the table to the right. You can customize the table — click the Settings button at the lower right to select data to display, view a subset of variables from the list, add or remove variables, and sort the list.

Manual DAQ Data Table

Click the menu below the left column to select parameters from a specific device. When LI-COR is selected, parameters from all models of LI-COR analyzers are given. Click any item in the left column to select it.

Shift + click to select consecutive files; Ctrl + click to select non-consecutive files.

Click the right arrow to add the selected items to the right column, which are displayed in the data table. If no items are selected in the left column, click the double arrow to add all items to the right column. In the right column, click on any item to select it, then click the green arrows to move it up or down. The green bar arrow auto-sorts the headers in order.

Click Set to apply the selection or Cancel to discard the changes.

Data Table

See Viewing a table of recent measurements for a summary.

Data Trends

See Viewing graphs of measurement data for information about the built-in graphing capabilities.

Data Export

See Exporting data to learn about data export capabilities.

Start Sample and Stop Sample

These controls start or stop the underway data collection process