Vernier LabPro - Manual (Page 9)

Revision Date: 08/02/02
LabPro Technical Manual 9
Timebase
Regardless of which type of data collection is used, the user must set the data collection rate based on the
available rates offered by LabPro. The range of possible times between readings is from 16,000 seconds to
2 x 10
-5
seconds for analog data collection with a single channel. With two analog channels read at the
same time, the shortest sampling time is 2 x 10 -4 seconds.
The data collection mode used affects the sample times allowed with LabPro. In normal mode, a system
tick of 100
µ
s is used to set the sample time. The sample time must be an integer multiple of 100
µ
s. Many
programmer designers choose to limit them to a finite number of rates, such as 10K, 5K, 2.5K, 2K, 1K,
500, 250, 200, 100, 50, 25, 20, 10, 5, 2.5, 2,and 1. At rates slower than 1 sample per second, the 100
µ
s
clock allows reasonable timing accuracy for any sample time requested.
In fast mode, a system tick of 400ns is used to set the sample rate. The sample time must be time period
multiplied by 400ns resulting in an integer value. Many programmers limit the choices to rates of:
50K, 33K, 25K, 20K, 10K
Refer to the LabPro Command Summary section for further details.
Data Retrieval
Data may be retrieved from LabPro in a several different ways. The most common way to collect data is to
send a get request. This will cause LabPro to return the next point in RT mode or to return the collected
data in NRT mode. Command 9 will collect a single point outside active data collection. This is useful
when wanting to monitor or test a channel. Command 8 can be used to return the most recent data point
collected during an NRT mode. Commands 5 and 12 is used to select specific data to be returned from
memory.
Miscellaneous Reference Information
LabPro Software Upgrades
LabPro uses FLASH technology, which allows you to easily upgrade to new software without buying a new
LabPro. As new functionality becomes available, you can download the software from the Vernier web site
to your computer and upgrade your LabPro.
Check the Vernier website (http://www.vernier.com) for upgrades, paying special attention to
compatibility statements. Directions for downloading upgrades will be given on the web site.
Archiving in LabPro’s FLASH Memory
LabPro has 24KB of FLASH memory that can be used for several purposes. In addition to allowing
updates to the operating system and storing the DataMate and other calculator programs, the FLASH
memory serves as an archive space for other programs and data.
To preserve collected data so that it can be retrieved at a later time, data sets can be stored in the FLASH
archive. To distinguish between different stored data sets, each data set can be given a name.
The FLASH archive can also store calculator programs and applications. This provides a convenient
location for storing frequently used programs or as a temporary storage to create more available memory