Vernier LabPro - Manual (Page 15)

Revision Date: 08/02/02
LabPro Technical Manual 15
timing data from each of the LabPro channels and calculate the desired result.
The continuous pulse mode (time gate is blocked) is used for several modes of timing. The following
examples detail some common timing tasks.
Timing how long a photogate connected to a DIG/SONIC port is blocked (Gate Timing)
This timing mode is used to time pulses through a single photogate. The times reported to the user
represent the duration of the photogate being blocked. LabPro may be used in two modes; pulse width or
continuous pulse width. The difference being that pulse width stops collection after a single value has been
collected. Since Logger Pro currently supports multiple pulses under gate mode, it might be more useful to
use the continuous pulse mode. The setup would be:
0 Clear all channels and reset the device
102,-1 Turn power on continuously. Not required, but a good idea.
1,1,14 Setup one dummy analog channel, if no other analog channels have been assigned
12,ch,3,1 Timing mode where ch is channel number 41 or 42 (DIG/SONIC1, DIG/SONIC2
respectively).
The 3 parameter refers to continuous pulse mode and 1 refers to active low pulse.
3,60,1000,0 Send trigger information for arbitrarily long experiment unless real analog data is being
collected. This example sets the experiment length for 1000 minutes (1000 readings,
each of 60 seconds).
The experiment will terminate after this 1000 minutes; however, we do not need to wait until the
experiment is over to retrieve data. The Command 12 is used to poll for and retrieve available data. The
program must poll LabPro to find the number of available data points that have been collected.
12,ch,0 Requests the number of available data
The number returned will corresponds to the number of available events. The program may use this
number to set up data retrieval as well as when to update data tables etc. LabPro reports two types of data,
the pulse width and the time at which the pulse ended relative to the beginning of the experiment. (Note
that the time the pulsed ended, not the time it started, is reported.) These times are reported back in units
of seconds.
12,ch,-1,n,m Requests the pulse width times beginning at event n and ending at event m.
For instance, if 10 data points were collected and only points 8 to 10 were needed this
would correspond to n=8 and m=10. If n and m are omitted, all events are returned.
The program may either “poll and retrieve” only new data or retrieve the entire data set each time. When
the user clicks on stop, the program should terminate data collection with a Command 6.
6,0
Timing how long each of two photogates is blocked, independently (Gate Timing with 2 Gates)
As mentioned before, the ports operate independently of each other so that the times reported back are
relative to each port. Simply setup and retrieve data as mentioned above using both ch 41 and ch 42.
0 Clear all channels and reset the device
102,-1 Turn power on continuously.
1,1,14 Set up one dummy analog channel, if no other analog channels have been assigned
12,41,3,1 Set continuous pulse mode for digital input 1
12,42,3,1 Set continuous pulse mode for digital input 2
3,60,1000,0 Send trigger information for arbitrarily long experiment unless real analog data is being
collected. This example sets the experiment length for 1000 minutes.