THORLABS DC2200 - External Modulation Mode; TTL Modulation Mode

© 2020 Thorlabs GmbH
3 Operating Instruction
19
3.3.6 External Modulation Mode
The external modulation signal (voltage) is applied to the SMA connector on the rear panel
and modulates the LED current. The allowed input voltage range is 0 to 5 V.
The applied voltage is converted into the LED current, the conversion coefficient (AKA modula-
tion coefficient) depends on the terminal and the value of LED current limit :
Terminal
LED Current Limit
Modulation Coefficient
LED1
0.0 to 4.0 A
800 mA/V
> 4.0 to 10.0 A
2000 mA/V
LED2
0.0 to 2.0 A
400 mA/V
The External Modulation panel shows above parameters:
3.3.7 TTL Modulation Mode
The SMA connector on the rear panel is used for TTL modulation input as well. The input
works with standard TTL level signals, the Low and High Level voltage ranges are displayed in
the panel:
TTL Low Level corresponds to LED OFF, TTL High Level - LED ON.
LED Current is the value that is applied to the LED when the TTL input is on H level; it can be
adjusted between 0 and the value of LED Current Limit (see upper line in the panel).
8
12
8
12