MTS Series 793 Application - Manual (Page 272)

MTS MultiPurpose TestWare® Data Acquisition Process Descriptions 272
Note There is a slight time delay between processes that start with a common
trigger (for example, two processes using the <Procedure>.Start trigger).
The process positioned the highest on the Procedure or Group table
starts first. When using data acquisition and command processes in
parallel, position the data acquisition process higher on the table than the
associated command process.
About Buffers
When you set up data acquisition, you specify the signals for which data is
acquired and the method of buffering.
Each type of buffer offers different operational characteristics:
• The buffer size specifies the maximum number of data elements the buffer
will store before data is written to disk. (A data element includes the data
from each selected signal.) You can set the buffer size between 1 and 16,000
data elements (default is 1024).
• Acquiring and saving data at fast rates can cause the computer to become
sluggish (slow to respond to selections). If the acquisition rates are too fast,
data over-run can occur. If this happens, the test stops and a message is
logged.
• Linear buffers can generate a Process.Buffer Full signal when the controller
acquires enough data elements to fill the specified buffer size. You can use
this buffer full signal to start or interrupt other processes in the procedure.
Linear buffer A linear buffer records data until it is full, then saves the data to disk. The size of
the buffer determines how much data is acquired before it is written to disk. Data
is continuously saved to disk until the process ends or is stopped. When the
process ends, any data in the buffer is sent to disk. The only limit is the size of
your hard drive.
Circular buffer A circular buffer records data continuously. When the buffer is full, new data
overwrites the oldest data. This type of buffering saves data to disk when the test
is stopped, when the process reaches its preset count, or when the process ends.
The circular buffer is useful for acquiring data just before some crucial event
(such as specimen failure), where data is not required for the whole test.