PASCO PS-2201-NI Load Cell, 5 N (NI) - Manual (Page 2)

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L o a d C e l l , 5 N ( N I ) P S -2 2 0 1- N I
2
Adding Load Cells
To measure the compression and tension forces in individual
members, add load cells to any PASCO Structure. Replace a
beam with two shorter beams and a load cell.
#5 beam = load cell + two #3 beams
#4 beam = load cell + two #2 beams
#3 beam = load cell + two #1 beams
Figure 3: A load cell combined with two #2 beams is the same length
as a #4 beam
Use thumbscrews to attach two beams to a load cell as shown in
Figure 3.
When using load cells, assemble your structure with the screws
loose. This will simplify the analysis by ensuring that the mem-
bers experience only tension and compression without moments.
Plug the RJ-50 connector at the end of the load cell cable into a
port on the NI-9237 Analog Input Module. See the instructions
that came with the Analog Input Module for details about how to
connect the load cell.
For more information about National Instruments hardware and
graphical programming environment, see the web site:
www.ni.com
Example: Bridge with Load Cells
Figure 4: Bridge with load cells
The bridge shown in Figure 4 incorporates two load cells to mea-
sure the tension or compression in various members amd a third
load cell to measure the shaking force provided by a mechanical
wave driver. Hanging masses are used to apply load. The
mechanical wave driver shakes the bridge structure at a con-
trolled frequency.
Combination of Load Cells
The 5 N Load Cell can be used in combination with other 5 N
Load Cells or with 100 N Load Cells (PS-2200-NI).
Calibration of Load Cells
Load cells are factory calibrated; however, you can recalibrate
them in software or on a datalogger. See the documentation for
your software or datalogger for instructions.
When calibrating a load cell, it is necessary to apply a known
load. Assemble the fixture shown in Figure 4 to support the load
cell. Hold or clamp the fixture at the edge of a table and hang a
mass from it as shown.
Note that the hanging mass applies tension to the load cell; there-
fore the known force that you enter into the software or datalog-
ger should be a negative value. For example, if the mass is 0.5 kg,
the applied force is -4.9 N.
Figure 2: National Instruments NI-9237
Analog Input Module
RJ-50
Receptacles
SF-9324 Mechanical
Wave Driver
Load
Cells