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<< Click to Display Table of Contents > LaserGate, LaserA, LaserB |
  
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<< Click to Display Table of Contents > LaserGate, LaserA, LaserB |
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All three outputs can operate in opto-insulated mode. For this the EXT_LASER_VCC (pin 11) and EXT_LASER_GND (pin 30) must provide the supply. EXT_LASER_VCC may not exceed +5 V in respect to EXT_LASER_GND.
As default, the optocouplers take their supply from internal VCC, which causes to eliminate the opto insulation. In this case the voltage of all 3 outputs are TTL compatible in respect to GND. The mode can be selected by solder jumpers on the bottom side of the USC-2 as shown in figures 5, 9 and 10.
Figure 9: Laser signal optocoupler external supply
Figure 10: Laser signal optocoupler internal supply (default)
The polarity of the LaserGate, LaserA and LaserB outputs is selected via software settings.
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During USC-2 startup and when the laser signals are disabled by software, the LaserGate, LaserA and LaserB will go into tri-state. It must be assured that the Laser defaults to a safe operation in this case. Potentially, a pull-up or pull-down resistor (about 4k7 ohm) has to be added to put the laser into a safe state. |
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For YAG style laser mode the output timing (active low mode) is as follows:
Figure 11: YAG laser control signals (active low)
The maximum output frequency for the LaserA and LaserB is 2 MHz, the period resolution is about 80 ns. The minimum output pulse width for LaserA and LaserB is about 167 ns.
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The minimal output frequency of the laser signals is 0.190 Hz. This results from the 50 kHz reference frequency with 18 bit resolution which is used for frequencies < 381.46 Hz (= 0x20000). |
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