:MEASure:TDR:DELTatime
Command Syntax
:MEASure:TDR:DELTatime
Query Syntax
:MEASure:TDR:DELTatime?
Description
Performs a Delta Time measurement on the selected waveform and shows the measurement at the top of the Results table. If the measurement listing is already shown in the Results table, the listing is moved to the top of the table. To select the waveform, use the :SOURce child command. The query form of the command returns the measured value. Delta time is the time difference from the specified edge on source one to the specified edge on source two. Use the :EDIRection, :ENUMber, and :ETHReshold child commands to define the source waveform's edges. Sources edges can be from different displayed waveforms. Use :MEASure:TBASe:METHod to change the definition of the waveform's top and base. Use :MEASure:THReshold:METHod to change the definition of the waveform's threshold.
Requires FlexDCA revision A.04.00 and above.
Measurement Ready?
To confirm that the measurement is ready to read, you can query the measurement's status:
if ('CORR' in Flex.query(':MEASure:TDR:DELTatime:STATus?')):
measurement = Flex.query(':MEASure:TDR:DELTatime?')
If averaging is turned on (:ACQuire:AVERaging), you can also confirm if the measurement result is ready by comparing the number of specified averages (:ACQuire:ECOunt?) versus the number of measurement sweeps that have occurred (:MEASure:TDR:DELTatime:COUNt?). The technique uses the :COUNt? common measurement query. For example,
if (Flex.query(':MEASure:TDR:DELTatime:COUNt?') >= Flex.query(':ACQuire:ECOUNt?')):
measurement = Flex.query(':MEASure:TDR:DELTatime?')
You can also use an acquisition limit lest to test that a number of waveform samples, or pattern acquisitions have completed before returning a measurement. Refer to the :LTESt:ACQuire:CTYPe command.
Common Measurement Child Queries
This command supports the use of the following common measurement queries: :LOCation?, :COUNt?, :MAXimum?, :MINimum?, :MEAN?, and :SDEViation?.
Measurement Identification
Avoid subtle programming errors! To ensure that the correct measurement is installed or queried, always explicitly identify a measurement when installing a measurement or querying a measured value, status, or detail. To identify a measurement, specify the measurement's source waveform (:SOURce child command). With some measurements, you may also need to specify other identifying values. Generally, when selecting a measurement using FlexDCA's GUI, if a dialog appears prompting you to select values, you should explicitly specify these values when remotely identifying the measurement. More information.
For example, to return the status of the measurement, :MEASure:TDR:DELTatime:
flex.write(':MEASure:TDR:DELTatime:SOURce CHAN1A')
if flex.query(':MEASure:TDR:DELTatime:STATus?') == 'CORR';
measurement = flex.query(':MEASure:TDR:DELTatime?')
else:
details = flex.query(':MEASure:TDR:DELTatime:STATus:DETails?')
reason = flex.query(':MEASure:TDR:DELTatime:STATus:REASon?')
Child commands for measurement identification:
:MEASure:TDR:DELTatime:SOURce:MEASure:TDR:DELTatime:REGion
Example Command Sequence
This sequence defines source one's edge number, direction, and threshold followed by source two's edge number, direction, and threshold. The delta time measurement is then started and the measurement result returned.
:SYSTem:MODE TDR :MEASure:TDR:DELTatime:SOURce1 TRACe2 // Defines first measurement edge :MEASure:TDR:DELTatime:ENUMber1 2 :MEASure:TDR:DELTatime:EDIRection1 RISing :MEASure:TDR:DELTatime:ETHReshold1 MIDDle // Defines second measurement edge :MEASure:TDR:DELTatime:SOURce2 TRACe2 :MEASure:TDR:DELTatime:ENUMber2 3 :MEASure:TDR:DELTatime:EDIRection2 FALLing :MEASure:TDR:DELTatime:ETHReshold2 MIDDle // Perform measurement :MEASure:TDR:DELTatime :MEASure:TDR:DELTatime?