Open-Loop Piezo Controllers
Chapter 3: Description
Page 6
Rev C, July 7, 2015
Chapter 3 Description
The MDT693B and MDT694B are precision, low-noise, low-drift, high-voltage
controllers for piezo actuators. They provide both local and remote control of piezo
drive voltages. The MDT694B supports one channel, while the MDT693B supports
up to three channels. They are well suited for single-axis and multiple-axis piezo
stages, such as Thorlabs’ MAX312D Three-Axis NanoMax Stage and PE4
Piezoelectric Actuator. Typical applications include remote alignment of single-
mode fiber couplers, high-resolution translation, microscopy, and remote
positioning.
The intelligent-speed-control potentiometers on the front panel allow for precise
setting of the output voltage over the full operating range. This fine control takes
full advantage of the inherently high resolution of the piezo element. The MDT693B
three-channel controller provides independent controls for each channel.
The drive voltage can also be controlled externally through a USB interface or by
applying an analog voltage (0 to 10 V) to the
EXT
BNC input on the front panel.
This voltage is summed with the manual control voltage and multiplied by a gain
of 15 V/V.
15
The external control voltage can be supplied by any stable voltage source,
including function generators, DAC outputs, or DC supplies. In addition, the
external voltage can be used as part of a feedback loop for automated alignment
systems. Since the external input voltage is summed with either the manual or the
USB voltage setting, the manual/USB control can be used for offset adjustments
without having to re-adjust the external voltage source.
The MDT693B and MDT694B include a voltage limit switch on the rear panel to
select the operating voltage range and gain for the unit. Each unit is shipped with
the voltage limit set for 0 – 75 V (Gain = 7.5 V/V) operation and may be adjusted
by the user to provide 0 – 100 V (Gain = 10 V/V) or 0 – 150 V (Gain = 15 V/V)
operation.
The Master Scan feature on the MDT693B allows all three channels to be
controlled by one manual adjuster or one external control signal. In this mode, each
channel can be precisely adjusted by an offset voltage (
INT
control knob for each
axis) and by a gain adjustment (
SCAN TRIM
adjustment for each channel). The
gain adjustment allows the output for each channel to be amplified from 80 to 120%
of the master control signal.
The MDT693B and MDT694B include 4-digit LED readouts for displaying real-time
output voltages of all channels.
These controllers contain a universal power supply. At the time of order, a
power cord specific to the region from which your order originates will be
included in the box. Should you need a power cord for a different region,
please contact your local Thorlabs tech support.
