iWorX FT-302 Specification sheet

FT-302
Overview
The FT-302 is a high-sensitivity dual-range research grade force transducer
designed to measure forces in the 0.005 to 10 gram and 0 to 100 gram ranges.
The FT-302 uses a reflective photomicrosensor to measure minute deflections of
the beam under load. The deflection of the beam is less than a few hundred
microns making the sensor very isometric. In addition its unique optical
technology makes it resistant to drift and offers intrinsically low noise
characteristics. The FT-302's on-board amplifiers reduce gain and adjustment
requirements on connected recording amplifiers. The transducer is highly resistant
to mechanical damage; its body is machined from aluminum and mounts to a
standard ring stand or with the handle removed clamp mounts. The cable that
connects the FT-302 to the recording amplifier is detachable allowing for multiple
cables to be configured for the user's choice of amplifiers. The FT-302 uses a
transducer input on an iWorx data acquisition system or an amplifier such as the
ETH-256 or ETH-401.
How to Use the FT-302
To use the transducer firmly secure it to a ring stand or other support. The long
axis of the transducer should be parallel to the work surface the attachment hooks
should be pointing downward toward the work surface and the cable connector
should be facing up. While alignment of the sensor with the work surface is not
critical linearity and sensitivity will decrease if the transducer is tipped more than
30-40°.
FT-302 Force Transducer
Technical
Note
iWorx Systems Inc.
www.iworx.com
LabScribe is a trademark of
iWorx Systems Inc.
©2015 iWorx Systems Inc.

1) Connect the cables first to the data acquisition system or amplifier and then to
the transducer.
2) After a 5 minute warm-up period check the output of the transducer on your
recorder. Zero the transducer output in LabScribe. If your data acquisition system
does not have enough range to zero the transducer use the zero adjustment knob
on the transducer.
3) Once zeroed calibrate the transducer. Typically this involves the use of two
weights that are appropriate to the range in which you are recording.
Calibration of the FT-302 Force Transducer
1) Type “No Weight” in the Mark box. Click Record and press the Enter key to
attach the comment to the recording. Record for ten seconds with no weight
hanging from the arm or hook of the transducer.
2) Type “5 grams” in the Mark box. Hang a 5 gram weight on the arm or hook of
the transducer. Press the Enter key on the keyboard. Record for ten more
seconds.
3) Click Stop to halt the recording.
Select Save As in the File menu and name the file. Choose a destination on the
computer in which to save the file. Click on the Save button to save the data file.
Unit Conversion
1) Scroll to the beginning of data when no weight was attached to the force
transducer.
2) Use the Display Time icons on the LabScribe toolbar to adjust the display time
of the Main window to show the complete calibration data on the Main
window.
3) Click the Double Cursor icon so that two vertical cursors appear on the Main
window. Place one cursor on the flat section of data collected when no weight
was attached to the force transducer and the second cursor on the flat section
of data collected when the 5 gram weight was attached to the transducer.
4) Click on the arrow next to the title of the force transducer channel to open the
channel menu.
5) Select Units from the channel menu and Simple from the Units submenu.
6) In the Simple Units Calibration window select 2 point calibration from the
pull-down menu in the upper-left corner of the window.
7) Put a check mark in the box next to Apply units to all blocks. Notice that the
voltages from the positions of the cursors are automatically entered into the
value equations.
8) Enter “Zero” in the corresponding box to the right of the voltage recorded when
no weight was attached to the transducer. Enter “5” in the box to the right of the
corresponding voltage recorded when the 5 gram weight was hung on the hook
of the transducer.
FT-302 Force Transducer
iWorx Systems Inc.
www.iworx.com

9) Enter the name of the units grams in the box below the weights. Click on the
OK button in the lower right corner of the window to activate the units conversion.
In the 10 gram range the FT-302 will deliver approximately 75 mV/gram at X1 gain
and approximately one tenth of that in the 100 gram range. From the graphs in the
technical data section of this manual you can see that the sensor is actually linear
to about 14 g in the 10 g range and about 140 g in the 100 g range. This upper limit
will vary from transducer to transducer but will never be less than 10/100 g. The
FT-302 is now ready for use.
Experiments
LabScribe experiments using the FT-302 Force Transducer include:
•Experiment AM-2: Skeletal Muscle Summation (found in the Animal
Muscle category of the LabScribe Settings menu as SkeletalMuscle-
Summation-Tetanus)
•Experiment AM-3: Heart Muscle (found in the Animal Muscle category of
the LabScribe Settings menu as HeartMuscle)
•Experiment AM-7: Crayfish Heart (found in the Animal Muscle category of
the LabScribe Settings menu as CrayfishHeart)
•Experiment AM-8: Mytilus Anterior Byssal Retractor Muscle (found in the
Animal Muscle category of the LabScribe Settings menu as ByssalMuscle)
•Experiment AM-9: Crayfish Gut Pharmacology (found in the Animal
Muscle category of the LabScribe Settings menu as
CrayfishGutPharmacology)
•Experiment AM-10: Summation Tetanus and Fatigue in an Intact Nerve-
Muscle Prep (found in the Animal Muscle category of the LabScribe
Settings menu as FrogNerveMuscle)
•Experiment AM-11: Earthworm Smooth Muscle Contractions (found in the
Animal Muscle category of the LabScribe Settings menu as
EarthwormSmoothMuscle)
Technical Data and Specifications
How It Works
The FT-302 uses a reflective photomicrosensor to optically measure the distance
of the blade from the sensor. The beam is positioned so that it stays within the
initial linear region of the graph. As a result beam movement at the 10 g point of
attachment is limited to less than 500 µm and movement at the 100 g attachment
point is approximately half that. Since the sensing technology is optical there is no
thermal drift. The sensor requires an amplifier/conditioner with an excitation voltage
of ±5 V. Full-scale voltage output swing for either range is approximately ±1 V so
amplification requirements for the conditioner are minimal. Since the FT-302 has
no integral cable detachable cables are used to connect to amplifiers and
FT-302 Force Transducer
iWorx Systems Inc.
www.iworx.com

conditioners in the lab. This means the FT-302 can be fitted with a variety of cables
and is suited for a wide range of applications including most smooth and striated
muscle experiments.
Linearity and Drift
The drift for the FT-302 is 35mg/Hour in the 0-10g range and 350mg/Hour in the
100g range. Typical performance/calibration curves are displayed below.
Amplifier Requirements
The FT-302 requires a standard bridge style amplifier input. The amplifier should
supply power at approximately ±5 V and have a differential input. The output
impedance of the FT-302 is low so it does not require high input impedance. The
connector used on the FT-302 is a standard DIN8. The connections are detailed
below.
FT-302 Force Transducer
iWorx Systems Inc.
www.iworx.com

FT-302 connector pin-out (solder side)
SPECIFICATIONS
Sensitivity >60 mV/g (0-10 g)
Drift <30 mg/hr (0-10 g) thermally
compensated
Noise 3.0 mg max (0-10 g)
Excitation voltage ±5 V
Dimensions 2.85 cm W x 7.6 cm L x 1.5
cm H
Handle length 6.45 cm
Part number FT-302
Care
Cleaning
Clean the FT-302 with a moistened cloth. Never immerse it in liquid. When
cleaning the attachment hooks it is unlikely that you will damage the sensor by
pushing the hooks up into the body or pulling on them within reason. The hooks
cannot be removed.
Storage
The FT-302 can be stored in its shipping container or left in the rack where it is
used. We recommend that the sensor be left powered whenever possible to avoid
the warm up period when it is switched on cold.
iWorx Systems Inc. 62 Littleworth Road Dover New Hampshire 03820
(T) 800-234-1757 / 603-742-2492 (F) 603-742-2455
FT-302 Force Transducer
iWorx Systems Inc.
www.iworx.com
iWorx Systems Inc.
www.iworx.com