The MDT630A is a pre-configured, piezo-based, motion control system that comes complete with drive electronics (MDT693A), user interface software, 3-axis flexure stage (MAX302), precision manual adjusters (DRV3), and all of the required cables to connect the system. The included NanoMax Flexure Stage offers 4 mm of coarse travel and 300 μm of fine travel controlled by the differential drives. Additionally, the unit has three piezoelectric actuators built into the housing to give an additional 20 μm of travel at a resolution of 20 nm.

The flexure design of the MAX312D ensures low crosstalk, high stability, and long-term reliability. The 3-channel controller offers a way to control the piezoelectric actuators wth high stability and accuracy. The controller cna be adjusted from the front panel or with the included, easy-to-use software through the RS-232 inteface.

All the cables required to connect the stage to the controller are included inthe kit. The MDT630A has a switch-selectable input voltage of 115 or 230 V and ships with either a US (imperial version) or European (metric version) power cord.

The piezo controller is our popular MDT693A three-channel piezo driver, which features the following:

• High Voltage Outputs (3 Ranges up to 150 V)
• High Current Drive Capability (60 mA)
• Precision, Low Noise Outputs
• Individual Channel Control or Master Scan Control
• Graphical User Interface Software

For detailed Specifications, User's Manuals, and Support Documentation for each of the products bundled into the MDT630A please follow these links:

MDT693A - Piezo Controller

MAX302 - Flexure Stage

DRV3 - Manual Adjusters

Piezo Driver Bandwidth Tutorial

Knowing the rate at which a piezo is capable of changing lengths is essential in many high-speed applications. The bandwidth of a piezo controller and stack can be estimated if the following is known:

1. The maximum amount of current the controllers can produce. This is 0.5 A for our BPC Series Piezo Controllers, which is the driver used in examples below.
2. The load capacitance of the piezo. The higher the capacitance, the slower the system.
3. The desired signal amplitude (V), which determines the length that the piezo extends.
4. The absolute maximum bandwidth of the driver, which is independent of the load being driven.

To drive the output capacitor, current is needed to charge it and to discharge it. The change in charge, dV/dt, is called the slew rate. The larger the capacitance, the more current that is needed.

So for example, for a 100 µm stack, having a capacitance of 20 µF, being driven by a BPC Series piezo controller with a maximum current of 0.5 A, the slew rate is given by

Hence, for an instantaneous voltage change from 0 V to 75 V, it would take 3 ms for the output voltage to reach 75 V.

Note: For these calculations, it is assumed that the absolute maximum bandwidth of the driver is much higher than the bandwidths calculated, and thus, driver bandwidth is not a limiting factor. Also please note that these calculations only apply for open-loop systems. In closed-loop mode, the slow response of the feedback loop puts another limit on the bandwidth.

Sinusoidal Signal

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The bandwidth of the system usually refers to the system's response to a sinusoidal signal of a given amplitude. For a piezo element driven by a sinusoidal signal of peak amplitude A, peak-to-peak voltage V_pp, and frequency f, we have:

A diagram of voltage as a function of time is shown to the right. The maximum slew rate, or voltage change, is reached at t = 2nπ, (n=0, 1, 2,...) at point a in the diagram to the right:

From the first equation, above:

Thus,

For the example above, the maximum full-range (75 V) bandwidth would be:

For a smaller piezo stack with 10 times lower capacitance, the results would be 10 times better, or about 1060 Hz. Or, if the peak-to-peak signal is reduced to 7.5 V (10% max amplitude) with the 100 µm stack, again, the result would be 10 times better at about 1060 Hz.

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Triangle Wave Signal

For a piezo actuator driven by a triangle wave of max voltage V_peak and minimum voltage of 0, the slew rate is equal to the slope, or:

or, since f = 1/T:

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Square Wave Signal

For a piezo actuator driven by a square wave of max voltage V_peak and minimum voltage of 0, the slew rate limits the minimum rise and fall time. In this case, the slew rate is equal to the slope while the signal is rising or falling. If t_r is the minimum rise time, then:

or