An arc lamp is not designed to be frequently turned off and on and doing so would dramatically lower its service life. In addition, each time it is turned on it requires a the power supply to ignite it with a 20,000V+ spark. Therefore an electronic shutter system inside the beam homogenizer is available to control exposure time. Please note that the shutter cannot be closed for long periods of time while the arc lamp is on because the high intensity beam can damage it. The electronic shutter if computer controlled with an activation time of <150ms.

External Electronics Controller

The shutter is controlled by an external box which provides it power and also an RS-232 interface to a Windows based computer. This external Electronics Controller has a two pin microphone connector for the shutter. The connection on the solar simulator is on the beam homogenizer's utility panel (see SS1K documentation for details). The DB9 connector connects the controller to a PC computer through the serial port. The “Shutter Open” light turns on when the shutter is opened. The “Power” light turns on when the controller is switched on.

Software Control

Included with this setup are:

The source code is included as a guide for customized programs using the SciShutter ActiveX control. The sciShutter ActiveX control drives the Sciencetech shutter using a background worker thread, thereby not tying up the main windows thread. This worker thread is started or stopped either by the ActiveX property AmStartedUp or by the SciShutter drop down menu (see below). Once the SciShutter is started up, one can open or close the shutter. This can be done in one of three ways:

1. Click on the Shutter Open or Shutter Closed radio buttons
2. Calling the SciShutter property AmOpen
3. Calling the drop down menu

Underneath the Shutter Open and Shutter Closed radio buttons is the status window. This will be painted red if the SicShutter has an error or is not started up, green if the SciShutter is busy, or white if the SciShutter is ready.

Drop down menu

The drop down menu opens when the user presses the mouse right button. The available commands are:

1. Start up - toggles the worker thread on off. This command is available by key board short cut Ctrl + T.
2. About - displays the AboutBox. Keyboard short cut is Ctrl + A.
3. Open - toggles the open/closed state of the Shutter. Keyboard short cut is Ctrl + O. Note that this command is only effective if the SciShutter is started up.
4. Setup - Allows the serial comm port to be changed.

Note that the keyboard short cuts are only available if the SciShutter control has the keyboard focus. A mouse click down on the control will set the keyboard focus.