Instruction manual

SI-MT/SI-MKB/SI-HTB
WORLD PRECISION IN STRU MENTS
17
In constant load experiments, the initial length of the muscle is set using the manual
adjustments of the muscle research platform. While the muscle is held at its initial length,
it is stimulated with tetanizing pulses so that the muscle develops its isometric force.
These stimulus pulses are controlled by the stimulation protocol created in MDAC and
sent from the analog stimulus output of the LabTrax 8/16. Once isometric tension is
established in the muscle, the capture command created in MDAC is sent from one of
the digital outputs of the LabTrax 8/16 to the SI-COLUB module. This command triggers
the SI-COLUB to read the initial force (F
0
) in the muscle and monitor the actual muscle
tension through feedback provided by the force transducer and its amplifi er (SI-BAM21-
LCB) or its anti-oscillation unit (SI-AOSUB). The SI-COLUB analyzes the inputs that it
receives and calculates the command that needs to be sent to the SI-MOTDB Linear
Motor Controller to maintain a load on the muscle as it slacks and reaches the force (kF
0
),
where k is set by the Force Step dial.
The time it takes to reach this force is determined by the Slack potentiometer. Once kF
0
is reached, the SI-COLUB sends position commands to the motor to maintain that force.
When the desired time at kF
0
is elapsed, MDAC sends another command through the
same digital output of the LabTrax 8/16 to the SI-COLUB module to return the muscle
to its original length and force (F
0
). The restretch time is determined by the Restretch
potentiometer.
The SI-COLUB offers three modes of operation: Constant Load, External Loop and Bypass.
SI-COLUB
Command
Linear Motor
Feedback
Measured Force
(from SI-AOSUB
or SI-BAM21-LCB)
External Trigger
(Like SI-SARCAM Camera)
Capture
Force Step
Bypass
×k
Constant Load Mode
External Loop Mode
Bypass Mode
Fig. 18 This block diagram graphically shows the three modes of operation in the Constant
Load module.