Differences

This shows you the differences between two versions of the page.

--- ffc:100 [2023/08/17 19:02] – [FPGA Control] Michael Radunsky
+++ ffc:100 [2023/08/22 23:46] (current) – external edit 127.0.0.1
@@ Line 78: / Line 78: @@
 The two channels of the SLICE-FPGA or SLICE-FPGA-II Offset Phase Lock Servo can be used to control a self-referenced phase lock of ƒ<sub>CEO</sub> and a lock of ƒ<sub>opt</sub> to a reference laser such as [[https://stabilaser.dk/stabilized-laser/|the Sabilaser 1542]] or [[https://rio-lasers.com/1550nm-laser-diode/|the RIO Planex]].
-====Slow Loop Feedback====
+{{ :ffc:updated_ss_home_menu_off.svg |}}====Slow Loop Feedback====
 Slow servo functionality is designed to allow indefinite FOPT locking times despite long-term drifts in the reference laser’s frequency outside the dynamic range of the FFC’s PZT feedback. This is achieved by slow temperature feedback to the oscillator of the FFC, which locks the PZT output voltage to a setpoint voltage near the middle of its dynamic range. To enable the slow servo, first lock FOPT normally, with the DAC 1 slider as close to centered as possible. Next, navigate to the home screen of the FFC-100 and press the “Slow Servo” button at the top of the screen (<imgref ss_home> and <imgref ss_enabled> ).
-<imgcaption ss_home|The slow servo button is located on the home screen to the right of the System Off/Laser On button.>{{ :ffc:ss_home_menu_off.png?400 |}}</imgcaption>
+<imgcaption ss_home|The slow servo button is located on the home screen to the right of the System Off/Laser On button.>{{ :ffc:updated_ss_home_menu_off.png?400 |}}</imgcaption>
 This will activate the slow servo but does not turn on the feedback. You can tell that the slow servo has been activated by the blue background on the “Setpoint [°C]” button.
-<imgcaption ss_enabled | When the slow servo is activated, the slow servo button will turn green, and the temperature “Target [°C]” and “Actual [°C]” buttons will turn yellow or green according to the current state.>{{ :ffc:updated_ss_enabled.png?400 |}}</imgcaption>
+<imgcaption ss_enabled | When the slow servo is activated, the slow servo button will turn green, and the temperature “Target [°C]” and “Actual [°C]” buttons will turn yellow or green according to the current state.>{{ :ffc:updated2_ss_enabled.png?400 |}}</imgcaption>
 This will activate the slow servo. On the FPGA software under the “Optical Lock” tab, the “DAC 1” slider should be gradually pushed and eventually stabilize in the center of its dynamic range. The gain of the slow servo comes preconfigured for each unit but can be adjusted via a menu accessed by pressing and holding the “Slow Servo” button on the FFC GUI (<imgref ss_menu>) **(We do not advise changing the gain without input from the Vescent technical staff)**.
-<imgcaption ss_menu | The slow servo menu allows the user to change the setpoint, gain, and polarity of the servo, and also to turn it on or off.>{{ :ffc:updated_ss_menu.png?400 |}}</imgcaption>
+<imgcaption ss_menu | The slow servo menu allows the user to change the setpoint, gain, and polarity of the servo, and also to turn it on or off.>{{ :ffc:updated2_ss_menu.png?400 |}}</imgcaption>
 While the slow servo is on, the color of the “Setpoint [°C]” button will change as the slow servo adjusts the temperature setpoint. A yellow color indicates that the PZT voltage is > 6V away from the setpoint (30V) and the temperature setpoint is being changed to compensate. This box will turn green when the PZT voltage is within the range of ±6V of the voltage setpoint. The color of the “Actual [°C]” box may also momentarily turn yellow as the temperature control servo corrects the cavity temperature when the temperature setpoint changes.
 Remember to shut off the slow servo by pressing the On/Off button in the slow servo menu, when unlocking the FFC-100.