In Probe Hold mode, the instrument optimizes measurement settings to allow reliable detection of stable signals (these settings are restored to their original values when you exit Probe Hold.) When you probe a signal, the instrument beeps (if the beeper is enabled) and automatically records a measurement when it finds a series of stable readings. You may take additional readings without pressing again.
Press Remove Last to remove the last reading from the list. Press Clear List to remove all readings from the list.
Because the Probe Hold display is optimized for the Probe Hold readings, you may not combine it with other display modes, such as histogram, bar graph, trend chart, or statistics. Probe Hold is a front panel only function. Readings recorded in Probe Hold mode cannot be accessed from remote. You can, however, take a screen capture of the probe hold display, see Utility Menu - Manage Files for details.
Math - Introduction The key is the shifted :
These math functions are available:Null l dB/dBm Scaling l Statistics l Limits
Math - Null A null reading is a value that is subtracted from all subsequent measurements. The value is specific to the present function and will persist even if you leave this function and return to it later.
One common use of this feature is to remove lead resistance from a resistance measurement. To do this, simply short the test leads together and press . For other measurement functions, place the probes across a null value circuit before pressing .
You can also specify a null value by pressing , changing the first softkey to Value, and entering the value using the arrow keys. To turn off the null feature, press again or press and set the first softkey to Off.
Math - dB/dBm Scaling The dB and dBm scaling functions, which apply to ACV and DCV measurements only, allow you to scale measurements relative to a reference value. NOTE Scaling is set to OFF when you change measurement functions (for example, changing from DCV to ACV). You must re-enable scaling after changing measurement functions. Front Panel Menus The dB and dBm functions are accessed from the second softkey in the menu.
NOTE For accurate displayed statistics of AC measurements in Front Panel mode, the default manual trigger delay ( > Delay Man) must be used. The first softkey on this menu (shown below) hides or shows the statistics below the data display (number, bar meter, trend chart, or histogram).
Remarks l The Span value is the Max minus the Min. l Press Clear Readings to clear reading memory and re-start statistics calculation. Math - Limits Limit checking indicates how many samples have exceeded specified limits and visually indicates when the limits are exceeded. Front Panel Menus The limits menu is accessed from the menu.
The first softkey enables or disables limits. The second and third softkeys specify the limits either as high and low values or as a span around a center value. For example, a Low limit of -4 V and a High limit of +7 V are equivalent to a Center of 1.5 V and a Span of 11 V.
The Beeper softkey enables or disables beeping when limits are violated (this also enables or disables the beeper for the other functions that use the beeper - probe hold, diode, continuity, and errors. Clear Condition resets the limit borders to green, as described below.
Limit Indications The display uses colors to indicate limits and limit violations. Trend ChartThe limit area is shown in light red on the graph. The limit borders are green (shown below) as long as the limits have not been exceeded.
When a limit is exceeded, the border turns red. In the image below, the top border is still green, but the bottom border has changed to red because the trend line has gone into the lower limit area.