thousands of apologies for not being able to explain in details about the SRM400 module.i am not very good at the descriptions.
Recently,i just bought the SRM400 module with the IC,PW0268 from the Pro-wave electronics corporation,http://www.prowave.com.tw .i have a problem with the measurement of the distance.
these are my methods:
1.i probed at the pin 11(sensor drive) of the IC-PW0268 to see the waveform output
2.i adjust the VR1,VR2 and Impedance matching transformer IFT--->purpose is i want to know how far can the 400EP14D(ultrasonic transducer) able to detect and echo back itself.
i hope my descriptions able to give some hints to you about whats going on.