Synrad p250, User Manual, Page: 98 / 106

TROUBLESHOOTING STATUS LED’S PAGE | 98
DC Pre-Charge fault
A DC Pre-Charge fault indicates that 48 VDC is not available at the input of one or more of the RF
modules. The RDY LED will flash in a 5-blink pattern. When this occurs, the Laser Ready output Opens. If
a DC Pre-Charge fault appears, the laser requires service—please contact NOVANTA Customer Service
or a NOVANTA Authorized Distributor.
No-Strike fault
A No-Strike fault occurs when the laser discharge does not strike (gas does not breakdown). During No-
Strike faults lasing is limited to a maximum 6.25% duty cycle (at a PWM Command frequency of 5 kHz),
or 5% at the user’s specified frequency during PWM signal application. In addition to the SHT indicator
flashing continuously an error message appears on the p250’s web page.
Humidity fault
During laser operation, monitor information on the p250’s web page including the relative humidity (RH)
value. When properly conditioned purge gas is flowing, the measured RH value should drop below 10%
within 10-15 minutes. If the RH value doesn’t drop below approximately 10% increase the gas flow rate to
the maximum specified value. Refer to purge gas specifications in the Technical Reference chapter
within the connection section. If the RH value continues to rise and reach 95%, lasing is halted, and a fault
is displayed in red within the error message section of the web page.
Blinking Shutter LED fault
Possible Causes:
• A No-Strike fault has occurred, possibly due to cold environmental conditions (common when
overnight temperatures are low) that may prevent the gas from breaking down into a plasma
state.
When this occurs, it may take 30 to 60 seconds for gas breakdown so the laser can begin normal daily
operation. There are three methods to force breakdown and clear the no-strike fault: (1) Apply tickle
pulses or a PWM Command signal (< 6.25% duty cycle) for 30 to 60 seconds.
When the gas breaks down into a plasma state, the laser will recover and begin lasing at the
commanded power level without cycling DC power. (2) Apply a single 20 μ s PWM pulse (at 5 kHz) while
monitoring the Fault Detected output. If the output closes, wait a minimum of 52 ms for the output to
open and then apply another 20 μ s PWM pulse. Repeat this sequence until no fault is detected—which
typically occurs in less than one second. Be aware that applying 20 μ s breakdown pulses in rapid
succession may cause laser output. (3) Apply a PWM Command signal (at < 5% duty cycle) until the fault
clears—typically less than 30 seconds. With either method, when breakdown does occur, lasing will
begin immediately at the commanded PWM parameters without cycling DC power. If the No-Strike
condition persists, contact NOVANTA or a NOVANTA Authorized Distributor.