THE CHART RECORDER

The Chart Status Display is a panel that provides real-time statistics on the state of the selected RAD8 or RAD7. In the case of the RAD7, the Chart Status Display includes the run and cycle numbers of the current RAD7 reading, the date and time of the next reading, and the counts that have accumulated in each window since the current test cycle began. Also included is the current air temperature, relative humidity, pump current, and battery voltage of the RAD7, and the device's internal clock settings and firmware information. The Chart Status Display for the RAD8 includes comparable information.

The Chart Status Display is automatically updated every five minutes, notwithstanding any immediate updates that occur when the Refresh Status Display button is clicked. Each time a status update is initiated for a RAD7, it takes at least 5 seconds for the latest status information to be transferred, but if a test cycle had just completed the process will take longer, because the latest cycle data will be obtained. RAD8 status updates do not take as long, due to the RAD8's faster data transfer speed. RAD7 status updates are timed such that the instrument is able to produce end-of-cycle printouts without being interrupted. Once the printing is finished, Capture will obtain a status update that includes the latest test data from the instrument.

Note that as the number of cycles in a test increases, more data has to be transferred at the end of each cycle, and the transfer time increases. This can become a problem if the Cycle Time is very short (e.g. 5 minutes) and there are a lot of cycles in a test, because a RAD7 will spend most of its time transferring data, as opposed to detecting radon. Therefore it is recommended that the Cycle Time be set to at least 10 minutes when using the Chart Recorder to monitor lengthly tests containing many dozens of cycles. The same issues applies when monitoring the status of a RAD8, but to a lesser degree.

To the left of the Chart Recorder is a panel of controls, many of which are similar to the controls in the Graph Window. The use of each control is explained below:

Open As Graph Button

Click the Open as Graph button to view the content of the Chart Recorder in a Graph Window. This makes it possible to examine the data in more detail, apply corrections, and export it in a variety of formats.

Concentration Units Pop-Up Menu

Determines the unit of measurement used to denote radon concentrations on the chart. The available options include Automatic, Bq/L, Bq/m³, dpm/L, and pCi/L. For the RAD7, the Automatic option causes radon concentrations to be presented in the unit to which the RAD7 itself has been set.

Temperature Units Pop-Up Menu

Determines the unit of measurement used to denote air temperatures on the chart. The available options include Automatic, Celsius, Fahrenheit, and Kelvin. For the RAD7, the Automatic option causes temperatures to be presented in the unit to which the RAD7 itself has been set.

Point Style Pop-Up Menu

Determines the appearance of the data points on the chart. The options are Normal, Shapes, B&W Shapes, and Hidden. The B&W Shapes option causes the graph to be rendered in black and white.

Line Weight Pop-Up Menu

Determines the thickness of the chart lines, as measured in pixels. This value may range from 1 to 4, or the chart lines may be hidden. A thicker line may be easier to read, but it can make the graph appear more cluttered than a single-pixel line.

Show Grid Lines Checkbox

Determines whether horizontal and vertical grid lines are visible on the chart. Horizontal lines indicate concentration, temperature, and humidity levels, while vertical lines represent time intervals.

Show Chart Legend Checkbox

Determines whether the legend is visible on the chart. The legend shows which colors represent which elements on the chart. To the right of the Show Chart Legend Checkbox is a small control for setting the placement of the Chart Legend. It may be positioned at any of the four corners of the chart image.

View Range Pop-Up Menu (RAD7 Chart)

The RAD7 Chart Recorder contains a View Range Pop-Up Menu, which determines the maximum visible time range supported by the accompanying View Range slider. For example, if the View Range Pop-Up Menu is set to 1 Day, dragging the View Range Slider all the way to the left will cause the Chart Recorder to display any RAD7 data that has been recorded within the past 24 hours. (Note that the right edge of the chart always represents the current time according to the RAD7.) If the View Range Pop-Up Menu is set to Automatic, the visible range is determined by the breadth of all the RAD7 data that has been loaded into the Chart Recorder thus far. By default the Chart Recorder will load the most recent run of data, regardless of the duration of the run, and the Automatic View Range setting will cause the chart to display all of this data. The full selection of View Range options include Automatic, 3 Hours, 1 Day, 1 Week, 1 Month, and 1 Year. When the View Range is expanded, Capture will load any additional RAD7 data runs that were recorded within the specified time span. When the View Range is narrowed, the scope of the View Range slider will be restricted accordingly, and data from outside the specified time range will be cropped off the left edge of the Chart Recorder display.

The RAD8 Chart Recorder does not contain a View Range Pop-Up Menu. Instead it contains only a View Range Slider and Hours Field, as described below.

View Range Slider and Hours Field

The View Range slider zooms the Chart Recorder view in and out. In the case of the RAD8, dragging the View Range slider all the way to the left causes the visible time range to expand to the full range of the current test. In the case of the RAD7, dragging the View Range slier all the way to the left causes the visible time range to expand to the range specified in the View Range Pop-Up menu; if the View Range menu is set to Automatic, the Chart Recorder will display all the data that has been obtained from the instrument thus far. When the slider is dragged all the way to the right, only data recorded very recently will remain visible. (The minimum time range is the amount needed to display 10 data points, and this will depend on the instrument's Cycle Time setting. For example, if the Cycle Time is set to 30 minutes, dragging the slider all the way to the right will cause the Chart Recorder to display any data recorded within the last 300 minutes, or 5 hours.) The accompanying Hours Field can be used as an alternative to the slider: input the desired number of hours and press Enter to set the chart range. The slider and the Chart Recorder display will be updated accordingly.

Radon, Air Temperature, and Relative Humidity Checkboxes

These checkboxes determine whether radon, relative humidity, and air temperature points are visible on the chart. The radon concentration data that is plotted on the chart is always taken directly from the RAD8 or RAD7, with no corrections made with respect to humidity or other factors.

RAD7 Printer Present Checkbox

The RAD7 Chart Recorder contains a RAD7 Printer Present checkbox, which is used to specify whether an infrared printer is being used with the RAD7. If this box is checked, Capture will allow printing to proceed uninterrupted after each record is recorded. If this box is not checked, updates to the Status Display will be given higher priority, potentially interrupting end-of-cycle RAD7 printing operations. There is no risk of such interruptions when monitoring RAD8 activity.

The Chart Recorder is particularly useful for monitoring groups of RAD8s or RAD7s. Device Groups are user-specified sets of instruments whose data is averaged and displayed as a single chart. For best results the timing of the devices in the group should be synchronized.

To configure a RAD8 Group or RAD7 Group, first make sure at least two RAD8s or RAD7s are connected and their icons are visible in the Main Window Toolbar. In the toolbar, select the Options Menu (which is labeled with a gear icon) and select Add RAD7 Group... or Add RAD8 Group...

The Group Configuration Window will appear, as shown below. This window is used to specify the Group's name and its member devices. After the Group has been configured, it will appear as an icon in the Toolbar, next to the other devices. A numeral on the icon will indicate how many instruments belong to the group. Selecting a Device Group causes displays a chart representing an average of the data belonging to the member devices.

Details on adding, managing, and removing RAD8 Groups and RAD7 Groups are provided in the Toolbar Commands section.

When the Chart Recorder is active, chart data may be logged to disk in any of several formats. Clicking the Settings button, which is accompanied by a logging indicator light to the left of the chart, brings up the Logging Settings Window, which is shown below.

The Logging Settings Window contains checkboxes for specifying whether to log Chart Recorder data to a radon data file, a column-based text file, and/or Capture Cloud. When logging to a radon data file or a column-based text file, it is necessary to specify a location for the file on disk. When logging to Capture Cloud, it is necessary to specify a name for the data set that will be stored in the Cloud. Specifying a description is optional, but recommended.

The Logging Frequency pop-up menu is used to control how often the data is logged. The default setting of Automatic causes data to be logged whenever the RAD8 or RAD7 records a new cycle.

After specifying the desired settings, click the Start Logging button. The Logging light on the Chart Recorder will turn green to indicate that logging is active. Logged data will be updated whenever the RAD8 or RAD7 records a new data point. It is possible to return to the Logging Settings dialog at any time by clicking the Settings button. If logging is active, it may be disabled with the Stop Logging button, found at the lower left corner of the Logging Settings dialog.

Note that even if logging is not specifically enabled, Capture will maintain records of raw Chart Recorder data in the Preferences folder. These files can be revealed at any time by selecting Show Chart Recorder Logs from the File Menu.

When the Chart Recorder is visible, it is possible to display the Chart Recorder Spectrum Window, which contains a diagnostic histogram representing the current spectrum for the selected RAD8 or RAD7. This histogram consists of 200 columns, each representing the number of counts that have accumulated within a corresponding 0.05MeV (50keV) spectrum channel. If the selected device is a RAD7 using RADLINK software version 0300 or newer, the spectrum data will comprise the current run, or most recently completed run. If a RAD7 uses an earlier version of RADLINK, such as version 0252, the spectrum will represent only the current cycle, and the spectrum will only appear if the RAD7 is Live. If the selected device is a RAD8, the Chart Recorder Spectrum Window will display the cumulative spectrum for the current test.

To display the Spectrum Window, choose Show Chart Recorder Spectrum Window from the Window menu in the menu bar. The spectrum histogram image is automatically refreshed upon the completion of each RAD8 or RAD7 cycle.

The spectrum data content can be exported to either a text file or the clipboard. To do this click the Export Spectrum Data button, found at the top of the Chart Recorder Spectrum Window. The exported data consists of 200 lines of text, one for each bar in the Cumulative Spectrum histogram. Each data line may contain up to five columns, as follows:

Channel: The channel number, ranging from 1 to 200.
Start MeV (Inclusive): The lower inclusive bound of the channel's energy range.
End MeV (Exclusive): The upper exclusive bound of the channel's energy range.
Window: The general category of the channel, for example, "218Po (A)", "216Po (B)", etc.
Counts: The number of counts recorded in the current channel.

These fields may be delimited by tab or comma characters. If the tab character is chosen, exported data files will use the .tsv file name extension, indicating Tab Separated Values. If the comma character is chosen, exported files will use the .csv extension, indicating Comma Separated Values. Either of these options allow the spectrum data to be opened in a spreadsheet or other tool for further analysis.