WPI SI-BAM21-LC User manual

WORLD
PRECISION
INSTRUMENTS
SI-BAM21-LC
KG Optical Force Transducer Amplier
Serial No._____________________
www.wpiinc.com
INSTRUCTION MANUAL
090519

SI-BAM21-LC
World Precision Instruments i
Copyright © 2019 by World Precision Instruments. All rights reserved. No part of this publication may be
reproduced or translated into any language, in any form, without prior written permission of World Precision
Instruments, Inc.
CONTENTS
ABOUT THIS MANUAL ................................................................................................................................. 1
INTRODUCTION ............................................................................................................................................ 1
Features.................................................................................................................................................... 1
How the Amplier Works...................................................................................................................... 2
Notes and Warnings .............................................................................................................................. 2
Parts List ................................................................................................................................................... 2
Unpacking................................................................................................................................................. 2
INSTRUMENT DESCRIPTION ...................................................................................................................... 3
Front Panel............................................................................................................................................... 3
Back Panel................................................................................................................................................ 4
Setup ......................................................................................................................................................... 4
OPERATING INSTRUCTIONS....................................................................................................................... 5
Calibrating the SI-BAM21-LC .............................................................................................................. 5
Making Measurements ......................................................................................................................... 8
MAINTENANCE .............................................................................................................................................. 8
ACCESSORIES................................................................................................................................................. 9
TROUBLESHOOTING .................................................................................................................................10
SPECIFICATIONS..........................................................................................................................................10
APPENDIX A: SETTING SYSTEM GAIN FACTOR.....................................................................................11
INDEX.............................................................................................................................................................13
DECLARATION OF CONFORMITY ............................................................................................................14
WARRANTY ...................................................................................................................................................15
Claims and Returns..............................................................................................................................15
Repairs ....................................................................................................................................................15

ii World Precision Instruments

SI-BAM21-LC
World Precision Instruments 1
ABOUT THIS MANUAL
The following symbols are used in this guide:
This symbol indicates a CAUTION. Cautions warn against actions that can cause
damage to equipment. Please read these carefully.
This symbol indicates a WARNING. Warnings alert you to actions that can cause
personal injury or pose a physical threat. Please read these carefully.
NOTES and TIPS contain helpful information.
Fig. 1—SI-BAM21-LC KG Optical Force Transducer Amplier
INTRODUCTION
The SI-BAM21-LC KG Optical Force Transducer Amplier is used in conjunction with the SI-H
Muscle Bath system and the related line of SI-Heidelberg muscle physiology products. The SI-
BAM21-LC powers the force transducer and outputs an analog voltage proportional to the
force applied to the force transducer. The force feedback signal can be multiplied by a factor
of 1, 2, 5 or 10 to provide better resolution for a minimal change in applied force.
NOTE : An optional factory setting increases the multiplier by a factor of 10, allowing the
signal to be multiplied by 10, 20, 50 and 100.
Features
The SI-BAM21-LC is a KG optical force transducer amplier that:
• Supplies an analog output (-10VDC to +10VDC) representing the force applied to the
tissue sample.
• Delivers a DC power supply voltage to the force transducer.

2 World Precision Instruments
How the Amplier Works
In a typical setup, a muscle is held by a force transducer and suspended in a tissue bath. The
force transducer is connected to the SI-BAM21-LC . As the muscle contracts or releases, the
force transducer converts the force into an electrical current signal which is proportional to
the force applied to the force transducer.
Before initiating an experiment, the SI-BAM21-LC must rst be zeroed. This sets the baseline
for measurements to follow.
The output signal is buered and multiplied by 1, 2, 5 or 10, depending on the front panel
Gain switch setting. The X10 setting is useful when output signals are extremely small. Finally,
the force proportional signal is sent through the output amplier circuit.
The analog output has a range of -10V to +10V that drives a data acquisition system,
multimeter or oscilloscope.
Notes and Warnings
NOTE : This system is designed for use exclusively with the SI-H line of KG force transducers.
It is not congured for use with the SI-H MicroTweezer or other types of force transducers.
Parts List
After unpacking, verify that there is no visible damage to the instrument. Verify that all items
are included:
(1) SI-BAM21-LC KG Optical Force Transducer Amplier
(1) Universal input (100-120VAC to 200-240VAC) AC adapter
(1) Power cord
(1) 13661 Potentiometer Adjustment Tool
(1) Instruction Manual
Unpacking
Upon receipt of this instrument, make a thorough inspection of the contents and check
for possible damage. Missing cartons or obvious damage to cartons should be noted on
the delivery receipt before signing. Concealed damage should be reported at once to the
carrier and an inspection requested. Please read the section entitled “Claims and Returns”
on page 15 of this manual. Please contact WPI Customer Service if any parts are missing at
941.371.1003 or [email protected].
Returns: Do not return any goods to WPI without obtaining prior approval (RMA # required)
and instructions from WPI’s Returns Department. Goods returned (unauthorized) by collect
freight may be refused. If a return shipment is necessary, use the original container, if
possible. If the original container is not available, use a suitable substitute that is rigid and
of adequate size. Wrap the instrument in paper or plastic surrounded with at least 100mm
(four inches) of shock absorbing material. For further details, please read the section entitled
“Claims and Returns” on page 15 of this manual.

SI-BAM21-LC
World Precision Instruments 3
INSTRUMENT DESCRIPTION
Front Panel
The front panel of the SI-BAM21-LC is shown in Fig. 2 .
Zero Button
Gain Switch
Data
Acquistion
Output
Force
Transducer
Connection
Fine Tune
Switch
Fine Tune LEDs
Zeroing LED
Gain Indicator LEDs
Gain Calibration
Potentiometer
Fig. 2—Front panel of the SI-BAM21-LC
Zero Button –When pressed, the SI-BAM21-LC output comes close to zero and the
Zeroing LED illuminates. Before any measurements are taken, the SI-BAM21-LC should be
zeroed to establish a baseline value for the force transducer.
Fine Tune Switch –This toggle switch allows you to ne tune the system after zeroing. Press
and hold the toggle switch to the left if you want to raise the baseline. Or, press and hold
the toggle switch to the right to lower the baseline. If the baseline is more that 0.3V above
zero, the High LED illuminates, and if it is less than –0.3V, the Low LED illuminates. When the
baseline is within 0.3V of zero, the LEDs are o.
Gain Switch –Under normal conditions, the Gain switch is set to X1. The current output
of the force transducer can be amplied by a factor of 2, 5 or 10. Press the Gain switch to
toggle between the gain settings. A Gain Indicator LED illuminates to show which gain
factor is applied. Larger gains are essential when working with extremely small forces.
Gain Calibration Potentiometer –Adjusting this potentiometer denes the gain applied.
Use the provided potentiometer adjustment tool (WPI # 13661 ) to calibrate the output
voltage scale factor to the force transducer current. See “Calibrating the SI-BAM21-LC ” on
page 5.
Data Acquisition Output –Connect a data acquisition system like WPI’s Lab-Trax to this
BNC connector to record the SI-BAM21-LC voltage output. For test purposes, a multi-meter
or oscilloscope may be connected using a standard BNC cable (WPI # 2851 ).
Force Transducer Connection –A SI-KG series force transducer is plugged into this DIN
connector. Align the pins, and insert the connector until it is fully seated.
Digital Interface –This connection is reserved for future use with an anti-oscillation unit.

4 World Precision Instruments
Back Panel
The back panel of the SI-BAM21-LC is shown in Fig. 3 .
Power
Switch
Power
Input
Connector
(2.5mm DC barrel)
Ground
Connector
(std. banana plug)
Fig. 3—Back panel of the SI-BAM21-LC
Power Switch –This toggle switch turns the power o (0) and on (I).
Power Input Connector –Plug the power cord into this connector.
Ground Connector –Use a ground wire with standard banana plug connector in this socket
to ground the entire unit to the desired reference.
Setup
Once the instrument has been inspected and accessories accounted for, make the cable
connections for system interfaces as shown in Fig. 4.
12V DC Power SupplyGround
Force Transducer
Data Acquisition (BNC)
Fig. 4—SI-BAM21-LC Connections
1. Connect the force transducer cable to the Force Transducer connection port (labeled
Transducer ) on the front of the SI-BAM21-LC . Align the pins and insert the connector.
2. Connect a BNC cable from the data acquisition system input to the Output on the front
panel of the SI-BAM21-LC .

SI-BAM21-LC
World Precision Instruments 5
3. Connect the AC power adapter to the Power Input (labeled 12V DC, 2.5A ) on the back
panel of the SI-BAM21-LC .
4. Turn the Power switch on the back panel on (I).
5. Allow 30 minutes warm up time for the system to stabilize with the transducer.
OPERATING INSTRUCTIONS
Calibrating the SI-BAM21-LC
Before taking measurements, the SI-BAM21-LC must be calibrated. Each SI-KG
force transducers shown responds linearly within its respective measurement ranges.
Consequently, the SI-BAM21-LC can be calibrated using only two reference points.
Force
Transducer
Force
Range
Range
(g)
Noise
(µN)
Compliance
(nm/mN)
Resonance
Frequency
SI-KG2 0-2 N 0-200 250 150 1.3 kHz
SI-KG2B 0-0.2 N 0-20 80 590 Hz
SI-KG4 0-50 mN 0-5 15 0.5 1.2 kHz
SI-KG4A 0-20 mN 0-2 4 1 1.2 kHz
SI-KG7 0-5 mN 0-0.5 0.2 10 250 Hz
SI-KG7A 0-5 mN 0-0.5 0.4 5 500 Hz
SI-KG7B 0-10 mN 0-1.0 1 1.5 550 Hz
SI-KG20 0-0.2 N 0-20 80 590 Hz
Under ideal conditions, use a model of SI-KG transducer that has a full-load range that is
no more than 120% of the maximum force that is anticipated. For example, if the greatest
force to be measured is 4g, use a transducer that has a full-load range of 5g, like the SI-KG4
transducer. To use the transducer at its full-load range, set the gain of the SI-BAM21LC to
X1. Higher resolutions are possible using the other gain settings (X2, X5, or X10). However,
using a gain of X10 allows only a tenth of the full-load range of the transducer to be displayed
as an output. In general, it is best to choose a gain factor that does not need to be changed
during an experiment, since each gain factor can have slight variances in its oset. If it is
necessary to switch between gain ranges during an experiment, check the osets in each of
the ranges after the calibration and before conducting the experiment. Then, use the Oset
Adjustment switch to set the minimum average oset between the ranges.
NOTE : Before calibrating the SI-KG transducer, position the tissue mount being used on the
actuator rod of the transducer. During the calibration, place the weight on the tissue mount
at the same position where the tissue will be attached.
The basic procedure for calibrating the SI-BAM21-LC involves:
1. Setting a zero reference point with the force transducer un-loaded.
2. Applying a load with a known mass to the tissue mount on the transducer.
3. Choosing one of the two calibration methods that best serves the application. Use the

6 World Precision Instruments
Gain Calibration Potentiometer to adjust the amplier’s output range to:
• Maximize the resolution for the intended measurement range. For the greatest
precision, maximize the resolution of the SI-BAM21-LC by calibrating the 10.0V
output of the amplier to 10-20% above the maximum expected force. For example,
if the maximum expected value is 4.0-4.5g, set the SI-BAM21-LC so that a 5g mass
yields a 10.0V output. The maximum expected output would then be 9.0V, with a
4.5g applied load.
• Numerically correlate the force with a voltage output. For quick visualization, you
may choose to establish a numerical correlation by calibrating the SI-BAM21-LC so
that a force like 5.0g generates a 5.0V output.
The following calibration procedure may be used with any SI-KG force transducer. For
illustration purposes, a SI-KG4 force transducer is used in the example. Note that a 5g mass
is the maximum force that a SI-KG4 can measure. If a gain of X10 is used with the SI-KG4
transducer, then 0.5g, which is about 10% of the total range of the SI-KG4 force transducer,
is the largest mass that can be used with this force sensor.
1. Connect the force transducer to the transducer input of the SI-BAM21-LC . Connect
the output of the SI-BAM21-LC to an input of a data acquisition system or a digital
multimeter. See “Setup” on page 4.
• If a multimeter is used to track the output of the amplier, set the scale of the meter
to measure DC voltages between -10.0 and +10.0VDC.
• If a computerized data acquisition system, like a LabTrax 8/16, is used to record the
output of the amplier, use the autoscale feature of the recording software to track
the changes in the output voltage as the calibration is performed.
2. Mount the force transducer on the calibration stand on the base of the SI-MT , SI-MKB
or SI-HTB system.
NOTE : The calibration stand holds the force transducer and its tissue mount in the
proper orientation for an accurate calibration. This angle is critical in establishing a
proper calibration ratio. When gravity pulls the mass hung on end of the tissue mount
down, the actuator rod of the transducer is pulled in the same direction as the force
created by the tissue used in the experiment. If the force is not pulling on the tissue
mount in this direction, the output signal has to be adjusted correspondingly.
Calibration
Stand
Force
Transducer
Assembly
Tissue
Mounting
Hook
Fig. 5—When the force transducer is properly mounted in the calibration stand on the muscle
tester, the force transducer is held at the same angle used when making measurements.