Vernier LabPro - Manual (Page 36)

Revision Date: 08/02/02
LabPro Technical Manual 36
pre-store – indicates how much data (as a percentage of all measurements to be made) prior to the
triggering event should be stored. This value can be an integer between zero (0) and one
hundred (100). For example, if pre-store is set to 10 with 1000 total measurements to be
made, 100 data points made before the trigger event will be reported.
extclock – used for internal debugging purposes and should always be set to zero (0).
rectime – indicates the how time should be recorded for each data point. The possible values are zero
(0) which disables time recording; one (1) which time-stamps data relative to the start of data
collection; and two (2) which time-stamps data relative to the time of the previous sample. In
the last case, the data taken before the trigger event will have negative times.
filter – indicates what type of smoothing should be applied to the collected data. The possible values
are
Filter Value Description Used with collection mode
0 No filter realtime or non-realtime
1 Savitzsky-Golay 5-point filter non-realtime
2 Savitzsky-Golay 9-point filter non-realtime
3 Savitzsky-Golay 17-point filter non-realtime
4 Savitzsky-Golay 29-point filter non-realtime
5 Median Pruning 3-point filter non-realtime
6 Median Pruning 5-point filter non-realtime
7 Light Realtime tracking filter realtime
8 Medium Realtime tracking filter realtime
9 Heavy Realtime tracking filter realtime
fastmode – indicates whether or not data will be collected at the maximum sample rate allowed LabPro.
In FASTMODE, only one channel can be active, and it must be an analog channel. Sampling
can be as fast as 20
µ
s/sample in this mode. FASTMODE is operational only for sample rates
from 50,000 sample/second to 5,000 samples/second. The possible values are zero (0) for
normal operation and one (1) for FASTMODE operation.
Return values: No information is returned.
Example 1: Start reading samples and displaying them every 0.5 second.
Computer
Calculator
s{3,0.5,-1} :Send({3,0.5,-1})
Example 2: Repeat last data collection.
Computer
Calculator
s{3,-1} :Send({3,-1})
Example 3: Collect data every 10 seconds for 600 seconds and apply a Savitzsky-Golay 9-point filter.
Computer
Calculator
s{3,10,61,0,0,0,0,0,0,2} :Send({3,10,61,0,0,0,0,0,0,2})
Triggering Details
Two types of triggering thresholds can be set in LabPro:
•
Hardware triggering is set to trigger on a specific voltage level established by the trigger
threshold parameter.
•
Software triggering is set to begin data collection on either the rising edge or falling edge of the
signal, depending on the trigger type and trigger threshold selected.