Instruction Manual

Revision Date: 08/02/02
LabPro Technical Manual 11
now support an Auto-ID feature. By using a 1 for operation in this command, LabPro will
automatically determine input configuration, conversion information as well as other sensor specific
information. If no sensor is found during an Auto-ID process, it defaults to the 0 to 5V input. Using 14
is a more manual example. It is more common to exploit the AutoID feature.
post-processing
= This option directs LabPro to process the collected data to calculate values such as
first and second derivatives. Sometimes it is desirable for the host to calculate these values instead of
LabPro. Here we use zero since it is not needed.
delta
= not used often, use zero
conversion
= The sixth number in the list is either 0 or 1. If it is a 1, the LabPro will use a user
programmed conversion equation to convert voltages to readings which correspond to a sensor like a
force sensor, pressure sensor, magnetic field sensor, etc. If it is 0, either an internal conversion or no
conversion equation will be used. You should use a 0 in this position if you are using an AutoID
sensor or want to read back raw voltage values. Use a 1 if you are using a Vernier analog sensor with a
DIN (5-pin) plug or other sensors that don't support AutoID.
Let's take a closer look at the second line of our sample program:
1,1,14,0,0,1
Command 1 used here sets up channel 1 to use a Vernier sensor and (since the 6th value is 1) to use a
conversion equation.
The third line of our sample program uses a Command 4. Command 4 is only used to set up the calibration
equation for an analog sensor, such as one of the Vernier probes with a DIN connector. With the proper
Command 4, LabPro will read correct values (newtons, degrees Celcius, % dissolved oxygen, etc). If you
are using an AutoID sensor, or you just want to read the raw voltage from an analog sensor, do not use a
Command 4. Skip this line. Another way of saying this is that if the sixth number in your Command 1 line
is zero, do not use the Command 4.
If an equation is to be used to convert voltages to other measurement units, Command 4 is used to load a
conversion equation to LabPro. Almost all Vernier probes use linear calibrations (1st order polynomial).
The calibration is specified by entering k
0
(the y-intercept) and k
1
(the slope). For this kind of calibration,
the form of the Command 4 line will always be:
4,
channel number
,1,1,k0,k1
In our sample program, the following line is used to load the conversion equation:
4,1,1,8.729,8.271
In this case, channel 1 is being used, with a intercept of 8.729 and a slope of 8.271. This is the proper
calibration for a Vernier Barometer, calibrated in atmospheres. Information on the proper Command 4 line
values for each Vernier sensor is included in the sensor documentation.
Command 3 controls the actual data collection. Here is Command 3 from the sample program we are
studying. It specifies taking readings every 0.25 seconds for 50 readings, and specifies that we should
record the time of each reading.
3,0.25,50,0,0,0,0,0,1
The syntax for this command is:
3, samptime, numsamp, trigtype, trigch, trigthres, prestore, extclock, rectime, filter, FastMode