Open-Loop Piezo Controllers
TTN011225-D02, Rev C
July 7, 2015
2. Turn the power switch (located on the front panel) to the
ON
position.
The digital displays should begin displaying the output voltage settings.
The factory default output setting is 0 V. The unit recalls the previous
output state when it is powered on.
3. Set all the output voltages to 0 V by pushing in the control knob and
rotating the knob counter-clockwise. The right-most decimal point will
blink after the knob is pushed in, indicating that the setting can be
adjusted. After 30 seconds of no activity, the display will stop blinking.
4. Adjust
the
INT
knob for each channel until the desired voltages are met.
5.7.
Using EXT Input BNC
The
EXT
input on the MDT693B and MDT694B is designed to allow the user to
modulate the output voltage or for use as feedback with positioning systems.
Examples of connections for this input include D/A systems, strain gauges with
support electronics, and function generators. The external control voltage is
summed with either the
INT
control knob or the USB voltage setting (changing the
voltage through USB will override the
INT
knob), up to a maximum control voltage
of 10 V. To use this feature, follow the steps below.
1. Attach a piezo to one of the high voltage output connectors on the rear
panel of the MDT693B or the front panel of the MDT694B.
Note:
The BNC center conductor is positive and the shield is at
ground potential. Be certain to match piezo polarity to the
connector since most piezo elements will be permanently
damaged if connected backwards.
2. Turn the power switch to the
ON
position.
3. Set all the output voltages to 0 V by pushing in the control knob and
rotating the knob counter-clockwise. The right-most decimal point will
blink after the knob is pushed in, indicating that the setting can be
adjusted. After 30 seconds of no activity, the display will stop blinking.
4. Connect an analog input signal (AC or DC), with a voltage between 0 V
and 10 V, to the
EXT
input BNC connector(s). The output for each
channel will follow the
EXT
input voltage with a gain of 7.5 V/V, 10 V/V,
or 15 V/V, depending upon the output voltage limit (see Section 5.5,
page 10).
Note:
Do not place a negative voltage on the EXT input BNC
connector. The MDT693B and MDT694B include reverse protection
diodes on the EXT inputs, designed to prevent the piezo output
from going negative. Presenting negative voltages for long periods
of time will damage these diodes and affect the operation of the
unit.
