Differences

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

--- d2:laser_controller [2019/03/25 20:59] – Michael Radunsky
+++ d2:laser_controller [2019/07/19 18:19] – Michael Radunsky
@@ Line 206: / Line 206: @@
 **Temp Servo Input (BNC)**
-The temperature servo input is summed to the T2 temperature set point signal and can be used to make electronic perturbations to the laser diode temperature.  The Temp Servo Input, has two settings: "Low" and "High" gain. The default settings is "Low" but can be changed by a switch accessible on the right side panel.
+The temperature servo input is summed to the T2 temperature set point signal and can be used to make electronic perturbations to the laser diode temperature.  The Temp Servo Input, has two settings: "Low" and "High" gain. The default settings is "Low" but can be changed by a switch accessible on the right side panel. See <imgref VPN00267>.
+<WRAP center round box 570px><imgcaption VPN00267|Temp control board with T2 Temp Servo Input gain switch circled>[{{ d2:d2-105:vpn00267.gif?nolink&550 | filler text }}]</imgcaption></WRAP>
 When the gain is set to "LOW", the slope for changing the set point is  ~95 mK/V.
-When the gain is set to "HIGH", turn the set point to the lowest desired temperature. Apply a voltage between -10V and 10V to TEMP SERVO INPUT to adjust the set point temperature. With this configuration, you can sweep the set point all the way from the low-temperature limit (-1°C) to the high-temperature limit (58°C). //NOTE that the Vescent Photonics Lasers should not be operated above 50°C.// The slope for changing the set point is ~9 K/V.
+When the gain is set to "HIGH", turn the set point to the lowest desired temperature. Apply a voltage between -10V and 10V to TEMP SERVO INPUT to adjust the set point temperature. With this configuration, you can sweep the set point all the way from the low-temperature limit (-1°C) to the high-temperature limit (58°C). //NOTE that the Vescent Photonics Lasers should not be operated above 50°C or below the dew point for your laboratory conditions.// The slope for changing the set point is ~9 K/V.
 The "Low" mode is designed for slow temperature feedback for long-term (days) stability of the locked laser.  Normally the Temp Servo Input is used to drive the dc value from the Current Servo Ouput on the Laser Servo to zero over long time scales.  In other words, temperature tuning is used to remove large, slow variations in the laser frequency.  To accomplish this, connect the Temp Servo Output from the Laser Servo module to the Temp Servo Input of the Laser Controller (with TEMP SERVO INPUT Gain is set to "Low").  This connection is only important if the user is trying to maintain a laser lock continuously over many days or even weeks.  Without feedback to Temp Servo In the Laser Servo can eventually run out of range.
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 **Setpoint In**
-SETPOINT IN is an analog input. When the SETPOINT ENABLE is LOW (0 V) the SETPOINT IN voltage value sets the injection current instead of the front panel dial.  Zero volts sets zero current and 6 V sets the maximum value of 200 mA (500 mA for 500 mA version).
+SETPOINT IN is an analog input. When the SETPOINT ENABLE is LOW (0 V) the SETPOINT IN voltage value sets the injection current instead of the front panel dial.  Zero volts sets zero current and 4 V sets the maximum value of 200 mA (500 mA for 500 mA version).
 This input is rolled off at 14 Hz, which is not much higher frequency than the front panel dial, which rolls off at 8 Hz, with a second pole at 4 Hz.  Therefore, noise can enter the circuit at this point and this input should be used with caution.  It is primarily intended for sweeping the current in order to measure PI curves and threshold values of laser diodes.  We do not recommend using this input for computer control of the injection current.