The key concept of the 9210 Multichannel Lock-in Amplifier is that several signals can be recorded simultaneously, all synchronized to the same internal master clock.
While the original application was AC calorimetry (AC steady state, 3-omega, relaxation), the system can also be used for direct AC impedance measurements on samples (superconductors, materials), transport measurements (e.g., quantum dots, thin films), multi-terminal measurements, Hall-probe arrays, AC susceptibility, thermal conductivity, laser stabilization, optical spectroscopy, interferometry, strain-gauge systems, vibration measurements, sensors (e.g., pressure, light, gas), multi-tip AFM,… so just like our standard lock-in amplifiers, the 9210 can benefit a large set of users for a large variation of applications.
The software is used to define an excitation signal using one of the ten function generators. The excitation signal is similar to the Oscillator Output on our other lock-in amplifiers, but unlike those it can be more than just a sinusoidal waveform. Rather, it can be anything from a sinewave, sawtooth, square wave or noise waveform, and with or without a DC offset. Two functions can be used on their own or added, subtracted or multiplied before being connected via the output(s) to the devices under test (DUT).
Two of the frequency generators also provide the reference signals for the lock-in demodulators, so the system can work in the equivalent of our existing Dual Reference or Dual Harmonic modes.
The signals back from the DUT are connected to the analog inputs, digitized, and fed to the dual phase lock-in amplifiers. The overall flexibility of the system allows many different experiments to be configured, including the following examples for a fully-equipped system:
Signal generator used to generate a complex excitation at the sum of two frequencies which is applied to the experiment; up to twenty signals from the experiment can be measured using ten parallel dual phase lock-in amplifiers running at one frequency and a second set of ten running at the other frequency.
Five signal generators at the same frequency generating five excitation signals with integrated current measurement, each connected to five different experiments. The resulting voltage signals from the experiment are detected by five parallel lock-in amplifiers, which when combined with the excitation current measurement, allows parallel measurement of impedance on five different samples.
The 9210 is not simply a multichannel lock-in amplifier, but can be used to create complex waveforms and analyze them – all in a single chassis. Sawtooth, square- and sinewave can be designed with such low repetition frequencies that they can also be used like the swept DC waveforms from other signal generators to perform I-V curve measurements, assign constant level voltages or currents, perform staircase scans and other variations.
Software
The LabVIEW based user interface, called MCL software, is available as free download. It allows full design of the output waveform and assignment to the outputs of the instruments and records the variables from the inputs the user selects. For every input, X,Y,R and theta as well as DC can be recorded.
Within the possibilities LabVIEW offers, MCL software lets the user graph the variables they wish to see (multiple graphs are possible in multiple windows) and allows further options like an oscilloscope function of a waveform or DC signal or fast Fourier-transformation (FFT) of an AC signal. Data can be saved in text formats for further analysis in external programs.
The 9210 is connected to the PC via Ethernet or through USB. For USB usage, NI drivers have to be installed. The customer can use the USB port on the back of the instrument to store data.
A LabVIEW2016 driver is available for users that want to integrate the 9210 into their own measurement setup. For more experienced users, this also allows further analysis of the data acquired with the 9210.
An XML source code makes it possible to integrate the 9210 into existing software written in text based languages such as MatLab, Python, C, or others.
The latter two options make the 9210 very interesting for OEM integration.