Agilent Technologies L4400 manual Initiated Measurement Mode, Ext Gate Input Init

L4450A 64-Bit Digital I/O with Memory and Counter 8

MEAS:COUN:TOT? RRES, (@1301)

Totalizer counts begin as soon as the channel is configured for the totalize measurement. You can stop a count by sending SENSe:COUNter:ABORt command and restart the count using the SENSe:COUNter:INITiate command.

The slope of the edges being counted can be configured using the SENSe:COUNter:SLOPe command. By default, when started, the totalizer counts rising edges.

Additionally, you can control when the edges are counted by setting the gate source to external and providing a gate signal on the gate input.

In external gate mode the counter totalizes when the gate is asserted. The gate time setting controls how long the counter totalizes. Once the external gate has been de- asserted a new measurement must be armed via the SENSe:COUNter:INITiate command. The figure below shows an externally gated totalizer measurement. The number of totalized counts is ‘5’ in this particular example.

Ext Gate

Input

Init

Initiated Measurement Mode

Measurements such as frequency, period, duty cycle, and pulse width require an initiate command and a gate. The SENSe:COUNter:INITiate command is used to initiate (arm) the measurement. The measurement is gated by either an internal (default) or external gate source. For measurements the external gate acts like an external trigger which triggers the internal gate timer.

The gate source is set using the SENSe:COUNter:SOURce command.

The default gate source is INTernal. The gate is the aperture over which the signal data is gathered. When the gate is internal, the measurement begins as soon as the INITiate command is received.

Since the measurements are all derived from the same basic measurement, you can retrieve the measured frequency, period, duty- cycle, and pulse width from the same initiated and gated measurement. For example, the following commands set the counter to measure the input signal for 1 ms using the internal gate. The frequency, period, duty cycle, and pulse width are returned as floating point numbers.

L4400 User’s Guide 217