The corresponding block-diagram shows how the frequencies are calculated for each step and set
via the VI “Input_LockIn.vi”. Then the channels 2 and 3 are polled for getting the amplitude and
phase at the actual frequency.
For the second step, please click with the left mouse button into the amplitude-graph at the
resonance frequency. This frequency will be set and the phase at this point will also be set as the
reference phase. These two values will be shown as “f0” and “PhaseX” accordingly. Now the two
diagrams become invisible and a new graph appears. The new diagram shows the new phase
multiplied with the chosen K
P
over the passing time, like shown in the picture below:
K
P
* Phase will be added to the set frequency “f0” and stored in “F
use
” to set the new used
frequency of the LockIn amplifier.
The corresponding scheme of this nose application is shown below:
Manual USB Lockin 250 – Rev. 1.03 dated 07/11/13
Page 34 (37)
PhaseX
IN
OUT
Δφ
φ
F0 + kP * Δφ
Uac
Output
Amplitude
* 1
* 10
* 100
