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4.2 Maintenance of the force transducer
The force transducer is the most delicate and fragile component of the Wire Myograph. Extreme care should be used when han-
dling or touching the force transducers.
As a part of daily maintenance, inspect the grease around the transducer pin extending from the transducer housing pinhole
before starting any experiment (see figure 4.1). Insufficient grease in this area will allow buffer and water to enter the transducer
housing and causing damage to the force transducer.
IMPORTANT NOTES
DMT RECOMMENDS THAT THE HIGH VACUUM GREASE SEALING THE TRANSDUCER PINHOLE IS CHECKED AND SEALED AT
LEAST ONCE A WEEK, ESPECIALLY IF THE WIRE MYOGRAPH IS USED FREQUENTLY.
DMT TAKES NO RESPONSIBILITIES FOR THE USE OF ANY OTHER KINDS OF HIGH VACUUM GREASE OTHER THAN THE ONE
AVAILABLE FROM DMT.
DMT TAKES NO RESPONSIBILITIES FOR ANY KIND OF DAMAGE APPLIED TO THE FORCE TRANSDUCERS.
Figure 4.1 Close-up of transducer pin from outside.
The orange arrow indicates the place that the grease needs to be applied to prevent water and buffer from damaging the transducer.
4.2.1 Checking the force transducer
The force transducer is a strain gauge connected to a Wheatstone bridge. The force transducers for each Wire Myograph are
housed in a separate, protective compartment (see figure 4.2). While the protective cover offers some mechanical protection for
the force transducers, they are still very vulnerable to applied forces exceeding 1 Newton (100 grams) or fluid running into the
transducer compartment due to insufficient greasing of the transducer pinhole.
If the force readings on the Multi Interface appear unstable or noisy, then first check that the Wire Myographs are connected
properly to the Multi Interface and that the chambers are plugged all the way into the Multi Interface.
If the force reading(s) are still unstable or noisy, then perform a new calibration as described in chapter 3.5.1 in Multi Myograph
System User Manual.
During the new calibration, monitor the relative force reading values in the Force Calibration sub-menu on the Multi Interface
The normal operating values for the force transducer during calibration should be between 3000 and 3500.
• If the value is 0, a single digit, or a three digit number, the force transducer is broken and needs to be replaced.
• If the value is less than 2000 or greater than 4500, the force transducer is broken and needs to be replaced.
• If the message “OFF” is displayed on the main page of the Multi Interface, even though the Wire Myograph is plugged in at
the rear of the Multi Interface, the force transducer is broken and needs to be replaced. In addition, if the force reading(s)
appear yellow in color, cannot be reset to zero, AND the transducer cannot be recalibrated, the force transducer is broken
and needs to be replaced.
If any other problems related to the force transducer are encountered, please contact DMT for advice or further instructions.
