Additional Staff Info
  Inductive Sensor Devlopment
A need for a reliable and fast method of detecting the precence of a a sample cap in the gripping jaw of the automated sample handler has led to the devlopment of a prototype sensor.

The new sensor is based on detecting the shift in resonance of a RLC loop caused by the presence of the permable iron sample caps. To achive this a small coil was wound on the gripper head in the area that will contain the sample cap. As a prototype model a culture tube of the same size was used.

  To sense the cap a 400kHz 5V Square wave is injected in to the sensor circit The resultant waveform is analised by two comparators, and the outputs of of the comparators is latched twice, Once at the leading edge of the pulse and once at the trailing edge. The use of two points of comparison helps us to disguish between noise and a real signal. The latch outputs are nanded to give a single yes or no check before being output to the automounter.

With the system in tune there is a more then 300mV shift in the peak heights with an ALS or Hampton style sample cap present, and an 150mV shift with a SPINE cap.

Updated 14 Nov 2005 Security Notice   Webteam   Site Map   Bio   PXRR   NSLS   BNL