Instruction manual

SI-H Muscle Testers

WORLD PRECISION IN STRU MENTS

Calibration

Stand

Force

Transducer

Assembly

Tissue

Mounting

Hook

Fig. 21 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.

3. Set the Gain switch on the front panel of the SI-BAM21-LCB to the gain (X1-X10) that

is suitable for the mass being used for the calibration of the selected transducer.

4. With no weight suspended from the transducer, press and release the Zero button

on the SI-BAM21-LCB. Use the multimeter or data acquisition system to monitor

the transducer output signal from the SI-BAM21-LCB or the SI-AOSUB. A reading

of 0.0VDC ±50mV should be seen. Remember that the zeroing error is larger with

higher gains. Use the Offset Adjustment switch to move the baseline of the recording

closer to zero if a smaller offset error is desired.

NOTE: When the Zero button is pressed, the zeroing LED illuminates to indicate that

the zeroing function is processing.

5. Use the Offset Adjustment switch to adjust the baseline to zero. Press and hold the

toggle switch up, if you want to raise the baseline. Or, press and hold the toggle

switch down to lower the baseline. If the baseline is more than 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 off.

NOTE: Once the baseline is zeroed to the desired position, do not touch the Offset

Adjustment switch until the calibration procedure is completed.

6. From the point on the tissue mount of the transducer where the tissue will be at-

tached, suspend a known mass that is close to the maximum range for the ampliﬁ -

cation factor and force transducer being used. In the example for the SI-KG4 force

transducer, a weight less than 5.0g is used for X1 or less than 0.5g for X10.

NOTE: Mass in grams can be converted to force in Newtons (N) by multiplying the

weight hung on the transducer by gravitational acceleration. Since force equals mass

times acceleration (F=ma), a 0.5g weight is equal to 4.9mN (0.0005kg * 9.8m/s

0.0049N). Make sure that the mass used to calibrate the transducer ampliﬁ er creates

a force that falls within the operating range of the force transducer and ampliﬁ cation

factor you selected.

7. After the suspended mass becomes motionless, monitor the output of the ampliﬁ er or

the corrected output of the anti-oscillation ﬁ lter while adjusting the Gain Calibration

potentiometer on the SI-BAM21-LCB. Use a potentiometer adjustment tool to adjust

the Gain Calibration potentiometer to any desired value up to the limit of 10.0V.