Calculating Measurement Cycle Time - Racal Instruments 2251A Operator's Manual

Calculating Measurement Cycle Time

5.2
Measurement cycle time is a concern in systems that contain a large number of instruments
or in systems where proper timing is crucial. The 2251A and the 2251A-02M are capable of
a variety of measurement functions. All measurement functions are dependent on the
measurement signal itself. Thus, measurement cycle time will need to be calculated for each
measurement signal and each measurement function used in the test program.
CALCULATING MEASUREMENT CYCLE TIME
The basic equation for all functions is as follows:
Measurement Cycle = Trigger Time + Measurement Time + Processing Time
TRIGGER TIME
Auto-trigger adds overhead to the measurement cycle time, because of the processing
required to set up the trigger-level. The amount of time required for the auto-trigger is
dependent on the frequency of the signal. The slower the input signal, the longer it takes for
the auto-trigger to complete its determination of the signal peaks and set the trigger threshold
at the correct point. The maximum amount of time is one (1) second per channel. If auto-
trigger is enabled for both channels, each channel will add to the measurement cycle time
regardless of whether the channel is actually utilized in the measurement process.
Auto-trigger Channel A: # # S (Frequency Dependent)
Auto-trigger Channel B: # # S (Frequency Dependent)
NOTE: Manual trigger does not add to the measurement cycle time, because the
trigger-level settings are set upon receipt of the command. It does not need
to wait for receipt of the signal. In most instances, auto-trigger makes up a
significant portion of the total measurement cycle time.
measurement cycle time is required, it is recommended that manual trigger
be used.
5-8
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
If minimum