User`s guide

E-Prime User’s Guide
Appendix A: Timing Test Results
Page A-11
interrupts (in the range of 7-9ms) per 10 seconds. This program would have to be shut down if
millisecond precision is required.
Mean Count by Delay
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Mean Count
Delay (ms)
Figure 8. Distribution of tick times from a laptop computer, showing frequent 8ms duration
interrupts (BinCount.ANL).
Configuring computers is a complex process and may require the assistance of a technician who
is experienced in installing and removing software applications and/or hardware. The main
strategy is to run a test. If timing is a problem, remove programs, and possibly hardware, until the
system can provide the precision needed for professional research. E-Prime provides the tools to
assist the researcher in detecting configuration problems that disrupt timing prior to the
implementation of experiments.
E-Prime Timing Tests
For research experiments, it is absolutely critical that the timing be tested rigorously. PST has
developed an automated timing test station that can evaluate timing accuracy on both Windows
(Intel, AMD) and Macintosh (PowerPC) computers. Under many test scenarios, the test station
can simulate responses made from an interactive subject.
Timing Station (TS) and Experiment Station (ES)
The Timing Station (TS) hardware consists of a Pentium 75MHz Gateway2000 PC running MS-
DOS 6.22. The machine is equipped with a BSOFT Engineering DIG130 digital I/O and
integrated clock card. The Experiment Station (ES), running the software and experiment scripts
to be tested, consists of any Pentium class PC (120MHz+) running Windows 95/98/ME. A digital
I/O card must be inserted into the machine prior to testing with the automated test station. All
tests that are conducted on the ES machine are written as E-Prime experiments. InLine script
was used to call Read/WritePort commands in order to control the TTL lines wired to the TS. The
data that is collected on the TS (a tab-delimited text file) is merged with data from the EDAT (E-
Prime data file) and imported into Microsoft Excel for further processing and analysis.