Strain measuring instrument
A strain measuring instrument drives strain gauges and strain gauge-type transducers (load cells, pressure transducers, etc.) with a Wheatstone bridge circuit and extracts minute resistance changes as strain values or voltage. It is broadly divided into static strain measuring instruments, which measure slowly changing loads or residual stress at multiple points, and dynamic strain measuring instruments, which capture rapid changes such as vibration and shock. Dynamic strain measuring instruments include carrier amplifier types, which excite the bridge with AC, and DC amplifier types, which excite it with DC and can handle frequencies from DC up to high frequencies. They are used for structural strength testing, stress measurement of mechanical components, and inspection and calibration of transducers.
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Strain measuring instrument
Dynamic Strain Measuring Instrument DSA-631
Model: DSA-631
Dynamic strain measuring instrument using carrier amplification method. Equipped with line length correction and disconnection check functions.
Minebea Mitsumi Inc.
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Strain measuring instrument
Dynamic Strain Measuring Instrument DAS-406C
Model: DAS-406C
DC amplification type dynamic strain measuring instrument. Frequency response from DC to 200 kHz.
Minebea Mitsumi Inc.
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Strain measuring instrument
Static Strain Meter PSD-704
Model: PSD-704
A portable static strain meter that allows easy verification of strain gauge transducer output in mV/V units.
Minebea Mitsumi Inc.
How to choose Strain measuring instrument
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1. Choose by static or dynamic, based on frequency bandwidth
Check that the frequency response range is sufficient for the speed of change of the phenomenon to be measured. For mainly static loads or temperature changes, a static strain measuring instrument is suitable; for vibration or shock, a dynamic strain measuring instrument is suitable. Some DC amplifier types handle high frequencies such as DC to 200 kHz, while carrier amplifier types are resistant to noise but have a comparatively narrower bandwidth.
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2. Confirm compatibility with the gauge resistance
Strain gauges are commonly 120 Ω or 350 Ω, so check that the resistance is within the connectable range of the instrument. Outside that range the bridge cannot be balanced and measurement is not possible. Also check whether the gauge factor setting range allows entering the value of the gauge used.
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3. Estimate accuracy from measuring range and non-linearity
Confirm that the maximum expected strain falls within the measuring range, then estimate the error from non-linearity (0.01 to 0.1 %F.S. for the listed products). Since %F.S. is based on full scale, measuring small strains over a wide range increases the relative error.
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4. Balance bridge voltage against heat generation and sensitivity
A higher bridge voltage increases output and improves the S/N ratio, but it also increases drift caused by self-heating of the gauge. Check whether a voltage suitable for the thermal conductivity of the bonded material, the gauge dimensions, and the recommended excitation voltage of the transducer can be selected.
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5. Confirm the required number of simultaneous measurement points
When acquiring stress distribution at multiple points simultaneously, insufficient channels prevent obtaining time-aligned data. Check whether the system can be expanded with add-on units, and whether each channel has an independent amplifier.
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6. Long cables and ease of use in the field
Long cables reduce sensitivity due to resistance, so check whether there is a lead wire length correction function. Also select according to the recording system and site conditions: wire break check, portable or benchtop type, output format, communication such as RS-232C, and power supply type.
This guide was written by AI based on the listed products' documents and specification items. Check each manufacturer's documents before adopting.