d2:laser_servo
Differences
This shows you the differences between two versions of the page.
d2:laser_servo [2018/11/14 17:38] – [Right Side Panel] Michael Radunsky | d2:laser_servo [2021/12/17 01:58] (current) – external edit 127.0.0.1 | ||
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Please read [[: | Please read [[: | ||
+ | |||
+ | [[https:// | ||
+ | [[https:// | ||
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The D2-125 Reconfigurable Laser Servo contains a tunable PI< | The D2-125 Reconfigurable Laser Servo contains a tunable PI< | ||
- | The main component in the Reconfigurable Laser Servo is the PI< | + | The main component in the Reconfigurable Laser Servo is the PI< |
The Laser Servo can be unlocked by a computer (via TTL control) to jump the output voltage to a set voltage difference from the current lock point, or to a specific voltage. This feature can be used to jump the laser frequency a known distance away and then relock to the original or a new lock point frequency. This feature can be used for auto-locking or relocking routines. | The Laser Servo can be unlocked by a computer (via TTL control) to jump the output voltage to a set voltage difference from the current lock point, or to a specific voltage. This feature can be used to jump the laser frequency a known distance away and then relock to the original or a new lock point frequency. This feature can be used for auto-locking or relocking routines. | ||
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=====Specifications===== | =====Specifications===== | ||
<WRAP center round box 600px> | <WRAP center round box 600px> | ||
- | | | **Value** | + | | | **Value** |
- | |**Input and Output Impedance**| | + | | **Input and Output Impedance** |
- | |**Output Voltage (main and aux)**| | + | | **Output Voltage (main and aux)** |
- | |**Input Voltage Noise**(( Referenced to 50Ω load))| | + | | **Input Voltage Noise**(( Referenced to 50Ω load)) |
- | |**Max Input Voltage DC Level**| | + | | **Max Input Voltage DC Level** |
- | |**Max Input Voltage Signal Amplitude**| | + | | **Max Input Voltage Signal Amplitude** |
- | |**Bandwidth**(( Oscillation frequency when Laser Servo locked to itself in proportional mode.))| | + | | **Bandwidth**(( Oscillation frequency when Laser Servo locked to itself in proportional mode.)) |
- | |**Proportional Gain (ref to DC Error)**\\ **Proportional Gain (ref to Input Error)**| | + | | **Proportional Gain (ref to DC Error)**\\ **Proportional Gain (ref to Input Error)** |
- | |**First Integrator**| | + | | **First Integrator** |
- | |**Second Integrator**| | + | | **Second Integrator** |
- | |**Differential**| | + | | **Differential** |
- | |**Differential Gain**| | + | | **Differential Gain** |
- | |**Auxiliary Servo Output | + | | **Auxiliary Servo Output |
- | |**Laser Freq. Jump**| | + | | **Laser Freq. Jump** |
- | |** Jump Time**| | + | | ** Jump Time** |
- | |**Ramp Amplitude (Max)**| | + | | **Ramp Amplitude (Max)** |
- | |**Ramp Frequency (on main servo output) \\ Ramp Frequency (on aux servo output)**| | + | | **Ramp Frequency (on main servo output) \\ Ramp Frequency (on aux servo output)** |
- | |**Dither Frequency (-PL only)**| | + | | **Dither Frequency (-PL only)** |
- | |**RF Output Max Amplitude (-PL only)**| | + | | **RF Output Max Amplitude (-PL only)** |
- | |**RF Output Impedance (-PL only)((Into a 1 MΩ load)) **| 50 | Ω | | + | | **RF Output Impedance (-PL only)((Into a 1 MΩ load)) ** | 50 | Ω | |
- | |**Ramp Centering Range **| ±5 | V | | + | | **Ramp Centering Range ** | ±5 | V | |
</ | </ | ||
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Located at the top of the front panel, the monitor section contains 6 BNC outputs for monitoring various signals used by the Laser Servo. The logic of the monitors is shown in <imgref image1> | Located at the top of the front panel, the monitor section contains 6 BNC outputs for monitoring various signals used by the Laser Servo. The logic of the monitors is shown in <imgref image1> | ||
- | <WRAP center round box 420px>< | + | <WRAP center round box 420px>< |
**Error In** | **Error In** | ||
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**Coarse Gain (seven-position switch)** | **Coarse Gain (seven-position switch)** | ||
- | The COARSE GAIN sets the overall proportional gain of the circuit without changing the location of any zeros or poles in the loop filter transfer function. | + | The COARSE GAIN sets the overall proportional gain of the circuit without changing the location of any corners |
The overall loop gain (controlled by both the COARSE GAIN and the FINE GAIN) should be set around the point that minimizes the RMS noise on the DC ERROR MONITOR. This can sometimes result in setting the gain too high because the DC ERROR MONITOR filters high frequencies and thus hides some of the gain peaking with high gain. To precisely set the gain, look at the noise with a spectrum analyzer through the AC ERROR MONITOR. | The overall loop gain (controlled by both the COARSE GAIN and the FINE GAIN) should be set around the point that minimizes the RMS noise on the DC ERROR MONITOR. This can sometimes result in setting the gain too high because the DC ERROR MONITOR filters high frequencies and thus hides some of the gain peaking with high gain. To precisely set the gain, look at the noise with a spectrum analyzer through the AC ERROR MONITOR. | ||
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**Auxiliary Servo Output** | **Auxiliary Servo Output** | ||
- | The AUXILIARY SERVO OUTPUT is generated from integrating the SERVO OUTPUT. | + | The AUXILIARY SERVO OUTPUT is generated from integrating the SERVO OUTPUT. |
**Ramp Offset** | **Ramp Offset** | ||
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===Auxiliary Servo: Gain (25-turn trimpot)=== | ===Auxiliary Servo: Gain (25-turn trimpot)=== | ||
- | This trimpot sets the gain for the AUXILIARY SERVO OUTPUT. The Aux Servo is a pure integrator and the gain ranges from 500 μs to 5 s. | + | This trimpot sets the gain for the AUXILIARY SERVO OUTPUT. The Aux Servo is a pure integrator and the gain ranges from 500 μs to 5 s. Full ccw sets gain to minimum (5 s), full cw sets gain to maximum (500 µs). |
<WRAP center round box 420px>< | <WRAP center round box 420px>< | ||
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** Ramp-> | ** Ramp-> | ||
- | This 2-position slider switch is only accessible by removing the right side panel (see above) and sets whether the ramp is applied to the SERVO OUTPUT or the AUXILIARY SERVO OUTPUT. It is factory set in the Ramp-> | + | This 2-position slider switch is only accessible by removing the right side panel (see above) and sets whether the ramp is applied to the SERVO OUTPUT or the AUXILIARY SERVO OUTPUT. It is factory set in the Ramp-> |
===Aux Gain: + / Aux Gain - (2-position switch)=== | ===Aux Gain: + / Aux Gain - (2-position switch)=== | ||
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** Aux: Bipolar / Aux: Unipolar (2-position slider switch) ** | ** Aux: Bipolar / Aux: Unipolar (2-position slider switch) ** | ||
- | This 2-position slider switch is only accessible by removing the right side panel (see above) and sets whether the AUXILIARY OUTPUT SERVO is unipolar or bipolar. It is factory set to be bipolar so the auxiliary output can range from -12 V to +12 V. For some applications such as driving a PZT, limiting the voltage range to positive values is necessary. | + | This 2-position slider switch is only accessible by removing the right side panel (see above) and sets whether the AUXILIARY OUTPUT SERVO is unipolar or bipolar. It is factory set to be bipolar so the auxiliary output can range from -10 V to +10 V. For some applications such as driving a PZT, limiting the voltage range to positive values is necessary. |
**Ramp Master / Slave (Jumper)** | **Ramp Master / Slave (Jumper)** | ||
- | This jumper is only accessible by removing the right side panel (see above) and sets whether the ramp input is in master or slave mode. It is factory set to be in MASTER MODE. In SLAVE MODE (jumper off) the RAMP signal is generated externally and input through the back panel RAMP I/O port. In MASTER MODE (jumper on) the ramp is generated internally and is sent out to the RAMP I/O port for driving other D2-125 Laser Servos configured in SLAVE MODE. | + | This jumper is only accessible by removing the right side panel (see above) and sets whether the ramp input is in master or slave mode. It is factory set to be in MASTER MODE. In SLAVE MODE (jumper off) the RAMP signal is generated externally and input through the back panel RAMP I/O port. In MASTER MODE (jumper on) the ramp is generated internally and is sent out to the RAMP I/O port for driving other D2-125 Laser Servos configured in SLAVE MODE. |
+ | |||
+ | The amplitude of the slave ramp is about -5x of the master ramp input (at slave Ramp Amp maximum). | ||
====Lock Guard==== | ====Lock Guard==== | ||
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<WRAP center round box 400px> | <WRAP center round box 400px> | ||
| **C** | **B** | **A** | ** Hold Time** | | **C** | **B** | **A** | ** Hold Time** | ||
- | |0ff|0ff|0ff| 60 µs | 150 µs | | + | |Off|Off|Off| 60 µs | 150 µs | |
- | |0ff|0ff|0n| 125µs | + | |Off|Off|On| 125µs |
- | |0ff|On|0ff| 250 µs | 600 µs | | + | |Off|On|Off| 250 µs | 600 µs | |
- | |0ff|0n|0n| 500 µs | 1.25 ms | | + | |Off|On|On| 500 µs | 1.25 ms | |
- | |0n|0ff|0ff| 1 ms | 2.5 ms | | + | |On|Off|Off| 1 ms | 2.5 ms | |
- | |0n|0ff|0n| 2 ms | 5 ms | | + | |On|Off|On| 2 ms | 5 ms | |
- | |0n|On|0ff| 4 ms | 10 ms | | + | |On|On|Off| 4 ms | 10 ms | |
- | |0n|0n|0n| 8 ms | 20 ms | | + | |On|On|On| 8 ms | 20 ms | |
</ | </ | ||
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{{ : | {{ : | ||
+ | |||
+ | |||
+ | While it is infrequent, the D2-005 power supply may occasionally radiate noise from the side of its chassis onto nearby electronics. This only occurs in some system configurations, | ||
**Absolute Jump TTL (BNC)** | **Absolute Jump TTL (BNC)** | ||
- | When asserted HIGH (5V) while in LOCK mode, ABSOLUTE JUMP takes the Laser Servo out of lock and conveys the voltage on LASER JUMP AMPLITUDE to the SERVO OUTPUT. | + | When asserted HIGH (5V) while in LOCK mode, ABSOLUTE JUMP takes the Laser Servo out of lock and conveys |
- | When asserted HIGH (5V) while in RAMP mode, ABSOLULTE | + | When asserted HIGH (5V) while in RAMP mode, ABSOLUTE |
- | When disconnected, | + | When disconnected, |
**Relative Jump TTL (BNC)** | **Relative Jump TTL (BNC)** | ||
- | When asserted HIGH (5V) while in LOCK mode, RELATIVE JUMP engages a sample-and-hold circuit and takes the Laser Servo out of lock. The voltage on the SERVO OUTPUT is the sample-and-hold value summed in with the LASER JUMP AMPLITUDE. For example, if the laser is locked and the SERVO OUTPUT is -200 mV, then engaging the RELATIVE JUMP and putting 300 mV on the LASER JUMP AMPLITUDE will make the SERVO OUTPUT | + | When asserted HIGH (5 V) while in LOCK mode, RELATIVE JUMP engages a sample-and-hold circuit and takes the Laser Servo out of lock. The voltage on the SERVO OUTPUT is the sample-and-hold value summed in with <color black/ |
When asserted HIGH (5V) while in RAMP mode, RELATIVE JUMP applies a DC offset equal to the LASER JUMP AMPLITUDE to the ramp signal at SERVO OUTPUT. When asserted LOW (0V) while in RAMP mode, the ramp signal is DC balanced. | When asserted HIGH (5V) while in RAMP mode, RELATIVE JUMP applies a DC offset equal to the LASER JUMP AMPLITUDE to the ramp signal at SERVO OUTPUT. When asserted LOW (0V) while in RAMP mode, the ramp signal is DC balanced. | ||
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If you are having problems locking the laser, it is a good idea to not use the AUXILIARY SERVO OUTPUT as this complicates the system. Once you get the locking to work properly, you can reconnect this cable. | If you are having problems locking the laser, it is a good idea to not use the AUXILIARY SERVO OUTPUT as this complicates the system. Once you get the locking to work properly, you can reconnect this cable. | ||
- | <imgref factory_settings> | + | <imgref factory_settings> |
<WRAP center round box 400px>< | <WRAP center round box 400px>< | ||
- | {{ {{ d2:d2-125:factory_settings.jpg? | + | {{ {{ d2:d2-125:factory_settings_red.png? |
+ | |||
+ | <WRAP center round box 60%>< | ||
+ | | **Corner** | ||
+ | | First Integrator (high freq.) | ||
+ | | First Integrator (low freq.) | ||
+ | | Second Integrator (high freq.) | ||
+ | | Second Integrator (low freq.) | ||
+ | | Differential (high freq.) | ||
+ | | Differential (low freq.) | ||
+ | |||
+ | </ | ||
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d2/laser_servo.txt · Last modified: 2021/12/17 01:58 by 127.0.0.1