DataTaker modes and inputs
This window lets you set up and the DataTaker's ability to return temperatures (instead of microvoltages) from thermocouples (note that the default setting is for copper-constantan thermocouples).  It also allows selection of differential or single-ended inputs for voltage measurements, or use of the high-speed counter:

In this example, there are 6 channels in use.  Two channels (#5 and #6) use copper-constantan thermocouples.  The remaining channels read voltages; two are connected as single-ended inputs (#3 and #4) and two as differential inputs (#1 and #2).

  • The DataTaker 800 has an additional mode setting that lets you set a trade-off between sampling rate and accuracy.   It's important to keep in mind that the two modes are 'global' in that they apply to all channels.
  • The default 'high-accuracy' mode provides good accuracy and zero correction, at the expense of sampling speed (maximum of about 10-12 samples/second, all channels combined*).

  • The alternative 'high-speed' mode reduces the number of raw samples averaged for each reading, increases the native sampling rate from 50 to 100 kilohertz, and omits zero correction (which will likely offset your readings somewhat from absolute accuracy; this is most important when measured voltages are small).   All this roughly doubles maximum sampling speed to 20-25 samples/second for all channels combined*.

  • If you switch off mains filtration (reducing noise from the AC power source), maximum sample rate rises to roughly 50-54 samples/second for all channels combined*.   Of course, if your AC power source is noisy, this may produce an ugly signal with high levels of AC noise artifacts.
    • You should use the 'high-accuracy' mode unless achieving the highest possible sampling speed is critical.
    •   Note that LabHelper automatically switches 'high-speed' mode ON if you request a sample rate faster than 10 samples/second.   This does NOT affect mains frequency filtering; you have to turn that on or off manually.

    The 'Mains frequency' buttons are for filters that reduce electrical noise from AC power supplies; depending on country (and sometimes region), the AC frequency is either 50 or 60 Hz.

    *This means that as you add channels, the sampling rate decreases:   for example, with 2 channels, the maximum sampling speed is about 5 samples/second in 'high-accuracy' mode.
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