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The
controller product line provides the source of
electrical power to open and close the laser shutter.
We offer a choice of AC line connection or DC supplied
voltage to operate the controller. Controllers are
calibrated and labeled for a particular model of
shutter.
The
shutter cable plugs into the controller receptacle. A
signal source, such as a pulse generator or
microprocessor output, is plugged into the BNC
connector or screw terminal. Internally, DC power
waveforms are generated and sent to the shutter
whenever the input signal is high.
Controllers also provide a manual toggle switch or
terminals for such connection, to allow the shutter to
be controlled manually. Safety Interlock models offer
additional output connections for shutter position
sensor electronics.
The
controller and shutter are very similar to a common
amplifier and speaker system. The controller, as an
amplifier, sends waveforms of inductive load power,
and the shutter, as a speaker, is the inductive load
receiving the electrical power. When the two are
closely matched for the application, the performance
of the design is maximized.
Simple DC circuits can be used to drive most
electro-mechanical devices, including laser shutters.
But when performance becomes demanding, the design
features of the controller are tailored for the
intended applications.
Models have design emphasis on one or more of the
following features: rapid switching speeds, high
repetition rates, exposure repeatability and jitter
control, low shutter heat dissipation,
shock/vibration/acoustic noise control, safety
interlocking, and special OEM considerations.
The
internal circuits vary greatly as performance features
are combined. It is very important to choose the
proper controller to assure maximum performance from
the laser shutter.
The
controllers are simple to use. After plug or wiring
connections are made, simply apply the control signal.
Whenever the signal is high (3-12 VDC), the shutter is
opened. When the signal goes low, the shutter closes.
The input is resistive, at about 3 K Ohms. Your signal
source must be able to source the required current,
typically 1 mA at TTL voltages.
Safety interlock models offer additional circuitry to
read the Position Sensors built into the laser
shutter. Either TTL totem pole outputs or mechanical
microswitch contacts are accessed at the rear panel of
the safety interlock controller models. These outputs
toggle between hi/low (open/close) as the shutters
cycle. The signals are useful for driving computer
safety systems, amplified door lighting systems, LED
displays, and processing software.
Other
safety interlock features include a reset button,
requiring acknowledgement of an interlock breach, and
an interlock continuity connection, typically used
with switches on laboratory doors or curtains.
When
selecting a controller, first choose between a
modulation type or safety interlock type, then review
the features that match your application.
Below
is an example of a simple Capacitor Discharge Circuit.
It is very simple, but robust and low cost. All of our
safety interlock shutters can be driven with this
circuit as well as with our controller models.
Modulation shutters typically cannot use this circuit
due to recharging limitations.
Capacitor Discharge Circuit
See our Application
Notes on User Built Circuits for details
of this
circuit and several other common circuits.
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