INITIAL START-UP
PAGE
|
57
Starting your I401 laser
Unlike other I401 lasers, the SHT LED on i401 lasers is dependent on the state of the RDY indicator.
Although a Shutter Open Request signal is applied, the SHT LED will not light while the RDY LED is Off.
Therefore, no power is applied to the RF boards until the RDY indicator is illuminated.
Each time an i401 OEM laser is powered up, a five-second delay occurs between the time the RDY
indicator illuminates and the i401 is permitted to lase. After the five-second delay (and while the SHT
LED is off), tickle is applied to maintain the laser in a ready state. Once a Shutter Open Request signal is
applied, and the SHT LED illuminates, apply PWM Command signals to begin lasing.
1
Apply a PWM Command signal (+5 VDC, 5 kHz square wave of 4
µ
s duration) between PWM
Input (Pin 9) and PWM Return (Pin 1) on I401’s User I/O connector.
2
Slowly increase the duty cycle of the square wave. The LASE indicator illuminates red when PWM
signal pulses are long enough to produce laser output (typically 7–10
μ
s at 5 kHz). The spot
where the beam hits the beam block increases in brightness, indicating an increasing power
output.
3
Remove the PWM Command signal from the User I/O connector. The LASE indicator turns off.
4
If you are connected to the i401’s Ethernet port, access the i401 web page to verify operating
conditions and functionality (refer back to Figure 1-13). See the Getting Started or Technical
Reference sections for details on accessing the I401 web page.
While purge gas is flowing, check the Relative Humidity value. The measured value should drop
to 0% (± 10%) within 10–15 minutes. If the relative humidity never drops below approximately 10%,
then increase the flow rate slightly.
5
Remove DC power from the laser
6
Shut off the chiller or otherwise stop coolant flow through the laser.
7
Shut off gas purge flow to the laser. In dirty or dusty environments, however, it may be necessary
to purge the laser continuously to prevent contamination of internal optics. If your Laser fails to
lase, refer to Troubleshooting in the Maintenance/Troubleshooting section for troubleshooting
information.
Caution: Possible Equipment Damage
Inlet cooling water temperature must always be maintained above the dew point to prevent
condensation and water damage to your I401 laser.
Danger: Serious Personal Injury
Because of phase differences, external tickle pulses may combine with the internally generated tickle
signal causing the LASE LED to flicker during the transition from tickle to lasing. Laser output may
occur if the LASE LED flickers.
