THORLABS SHB025 - External Modulation Modes

Ø1/4" Shutters and Controller Chapter 4: Setup and Operation
Rev F, January 18, 2023 Page 7
Condition
Shutter State
Open
Closed
Depressing the ENABLE button
Closes
Opens
Power plugged into either wall outlet
or controller
Closes
Stays Closed
Power button depressed to turn on
Closes
Stays Closed
Power button depressed to turn off
Closes
Stays Closed
Unplugging power cord from wall
outlet or controller
Stays Open
Stays Closed
Unplugging shutter from controller
Stays Open
Stays Closed
Plugging shutter into controller while
it is on
Shutter will revert to whatever state it indicated
by the controller, usually no change.
To manually control the shutter, after powering on the unit, simply press the ENABLE
button. This will open the shutter. Depressing the button a second time will close the
shutter. If the unit is in External Modulation Mode, pressing the ENABLE button once
will put the device into Manual Mode without opening the shutter and the Status LED
will flash four times.
The SHB025(T) is set to the last mode it was in when it is powered on. Pressing the
ENABLE button puts it in Manual Mode if it was in Protected or Unprotected External
Modulation Mode. This disables the external modulation input connector (the BNC
connector port labeled TTL Input on the controller). To return the device to Protected
External Modulation Mode, press and hold the ENABLE button for 3 seconds.
The Status LED will flash two times to indicate the device is in Protected External
Modulation Mode, and the shutter will start changing state provided there is a TTL signal
active on the port.
4.3. External Modulation Modes
CAUTION
Prolonged modulation of these shutters will eventually result in premature
component wear and failure. This device is not intended for long-term
continuous modulation.
To control the SHB025(T) shutter state using an external, modulated TTL signal,
connect the signal source to the shutter controller at the BNC TTL Input connector.
Activate the TTL signal source. The shutter will be in the last state it was in when
powered on, therefore if it does not begin modulating, press and hold the ENABLE
button to enter the Protected External Modulation Mode. The TTL requirements are:
• TTL Level Input Voltage
o A High Logic state is 2 – 5 V
o A Low Logic state is 0 – 0.8 V
• At the Modulation Input
o Logic Level High opens the shutter
o Logic Level Low closes the shutter