THORLABS SHB025 User Manual page 5

Ø1/4" Shutters and Controller Chapter 3: Description
Chapter 3 Description
The SHB025 and SHB025T are one-quarter-inch-aperture, high-speed, bladed
shutter, driven by the included shutter controller. The shutter connects to the
controller through a shielded four-conductor cable using a four-pin, mini-DIN
connector. The included controller provides the drive levels required for optimal
performance and monitors the state of the shutter. The controller has a BNC
connector for external modulation as well as an interlock output jack for safety. A
switching power supply is included.
The SHB025(T) can be controlled directly from the buttons on the controller or via
an external modulation source. There are two buttons on top of the controller unit,
one to turn the power on and off and the other, labeled as ENABLE, to open or
close the shutter. When the unit is first powered on, it is in the mode it was last,
being either Manual or External Modulation Mode expecting input from the external
modulation port. Manually depressing the ENABLE button will open and close the
shutter. To use the modulation input, press and hold the ENABLE button for 3
seconds.
The external modulation port can drive the shutter up to a maximum frequency of
50 Hz. In normal operation, when the logic of the external modulation pulse is high,
the shutter will open. When it is low, the shutter will be closed. In normal operation,
the shutter will shut down if it is run at its max frequency for too long to prevent
overheating. In Unprotected Mode, this safety feature is disabled and the unit may
be damaged if run too long without thermal control.
The SHB025(T) has many safety features. The controller detects the state of the
shutter using an internal optical sensor inside the shutter package. The optical
sensor detects the shutter blades' position, confirming if the shutter is open or
closed. This feature, when used with the interlock connector, makes this ideal for
applications where a laser safety lockout is required. In the event of a failure such
as a blade jam, the SHB025 will shut down. This changes the state of the interlock
and LED light will turn red. The SHB025 can detect when the blades are not
operating at the set frequency and will shut down to prevent damage to the
SHB025.
The SHB025(T) comes with the shutter head, controller, external switching supply,
AC cord, and this manual.
Rev F, January 18, 2023 Page 3