A streaming serial device (or serial stream, if you prefer) sends a periodically updated stream of text-format data consisting of numeric variables (delimited by commas), with each batch of data concluded with a carriage return character.   There may be one or more non-numeric text variables as well.   Selecting this option opens the window shown below,in which you can select which of the variables in a 'stream' to use.   Variables are shown in the 'value' column.   Text blocks that do not convert into numbers (i.e., they contain characters other than " + - . 0 1 2 3 4 5 6 7 8 9 ") are shown as blank ('--').

The program knows the parameters of a number of streaming serial-capable instruments (mainly those from Sable Systems), such as the Sable RH-100 relative humidity sensor in the example at right.  For a 'known' instrument, appropriate variable labels are automatically inserted.   If your instrument is not being read correctly, try clicking the Reload data button.

• If your instrument is not recognized by LabHelper, fill in the 'label' edit fields with appropriate information (variable names) and click the 'Add to Instrument Database' button.   You will be asked for a name for the instrument in a small window, and then the name and channel labels will be appended to the instrument list.   This is a small text-format file called 'serial instrument database.txt', which is internal to the LabHelper application.

• Channel numbers are not selected in the usual way.   Instead, click the 'select' check buttons to indicate which subset of the variables you want to record.   When you select a variable, the computer automatically gives it a channel number.they are assigned according to the order of selected variables in the sample string (shown in the rightmost column).   Do not attempt to adjust this in the Display Setup window or problems will ensue.

• Note that responses to button clicks, etc. can be slow in this window, since the software spends a lot of time reading and verifying the serial data.   Responses when gathering data can also be slow. For example, to enter a marker, hold the key down until the marker appears.   Similarly, click and hold a toobar icon until you get the response you want.

• In this mode there is no 'handshaking:' the serial device is not controlled by the computer (it's just 'listened to').   LabHelper uses a simple and occasionally imperfect check on each sample string to make sure it is complete before it is accepted for processing, but the update rate is pretty much entirely a property of the serial instrument.

• You can enter channel labels here, or later in the Conversions window or the Display setup window.

• The program will use the last-received data from each instrument channel to generate and upper or lower limit for screen display, as shown in the the Display setup window.   These are arbitrarily set to ~1.2 times the current data value; you will likely want to change them before starting to acquire data.