Measurement device and material tester
Once a sensor amplifier side connector of a cable unit for interconnecting a detector and a sensor amplifier is connected to the sensor amplifier, a gain resistor on the cable unit side and an instrumentation amplifier of the sensor amplifier are interconnected and the gain of the instrumentation amplifier is determined. As a result, the gain of the instrumentation amplifier is determined such that the magnitude of a signal that the sensor amplifier receives from the detector becomes a magnitude optimal for an analog circuit in the sensor amplifier.
1. A measuring device comprising:
a detector converting a change in physical quantity generated in a measurement object into an electric signal and outputting the electric signal;
a sensor amplifier to which the output signal of the detector is input;
and
a cable unit connecting the detector and the sensor amplifier to each other,
wherein the cable unit includes a nonvolatile memory storing information on the detector and a resistor determining a gain of an instrumentation amplifier inside the sensor amplifier to a gain depending on the information on the detector.
2. The measuring device according to claim 1 , wherein the cable unit includes:
an electrical calibration circuit having a calibration bridge and a calibration resistance;
a switch switching a state of the signal input from the detector to the instrumentation amplifier; and
a switch switching a state of connection between the electrical calibration circuit and the instrumentation amplifier.
3. A material testing machine performing material testing, comprising a load mechanism giving a test force to a test piece, and the measuring device according to claim 1 .
4. The material testing machine according to claim 3 , wherein the measuring device is a measuring device including a load cell detecting the test force given to the test piece or a measuring device including a displacement meter detecting displacement generated in the test piece.
5. A material testing machine performing material testing, provided with a load mechanism giving a test force to a test piece, and provided with the measuring device according to claim 2 .
6. The material testing machine according to claim 5 , wherein the measuring device is a measuring device including a load cell detecting the test force given to the test piece or a measuring device including a displacement meter detecting displacement generated in the test piece.