In order to solve the problems that the ultrasonic wave receiving probe drive of the existing experimental instrument cannot be automated and the displacement precision is not high

the distance measurement cannot be digitally displayed and the precision is not high

and the experimental temperature cannot be changed

a digital variable temperature experimental instrument is proposed and designed. In this design

the stepping motor driver 16 subdivides and drives the stepping motor to drive the screw to rotate

and then the screw drives the receiving probe to move; a 1 000 pulse incremental photoelectric encoder is set on the screw to achieve distance measurement. Its semiconductor refrigeration chip is under constant external temperature control under the control of a constant temperature controller. The experimental results show that the displacement precision of the experimental results can reach 0. 3 μm

the measurement precision can reach 1 μm

the constant temperature error is ± 0. 1 ℃

and the error between the measured sound velocity and the theoretical sound velocity is 3. 33 ‰

which can effectively improve the experimental precision and use effect. The design has certain market application value.