Synrad p250, Руководство пользователя, Страница: 38 / 106

RF POWER SUPPLY PAGE | 38
RF power supply
p250 lasers are driven by two compact RF modules mounted internally in the laser chassis. Each RF
module converts 48 VDC input power into a radio frequency (RF) signal that is then amplified and
routed to its corresponding electrode structure in the laser tube where it excites the gas mixture in the
tube to produce lasing.
Control circuity built into the laser interrupts operation if any critical parameter is violated. Switches and
sensors on the control board monitor various conditions and parameters that, if exceeded, pose a risk of
potential damage to the laser. Additionally, laser operation is interrupted in response to the following
conditions: (1) the EM shutter is closed; (2) the Shutter Open Request input signal is missing; (3) an over
temperature or low coolant flow condition occurs; (4) the Remote Reset/Start Request input signal is
enabled; (5) the Remote Interlock input signal is missing; or (6) any fault is present.
Cooling & Setting coolant temperature
Choosing the correct coolant temperature is important to the proper operation and longevity of your
laser. When coolant temperature is lower than the dew point (the temperature at which moisture
condenses out of the surrounding air), condensation forms inside the laser housing leading to failure of
laser electronics as well as damage to optical surfaces.
The greatest risk of condensation damage occurs when water-cooled lasers are run in a high heat/high
humidity environment and the chiller’s coolant temperature is colder than the dew point temperature of
the surrounding air or when the system is shut down, but coolant continues to flow through the laser for
extended periods of time.
Cooling guidelines
NOVANTA® recommends that the laser’s cooling fluid contain at least 90% water (distilled or tap) by
volume. In closed loop systems, use a corrosion inhibitor such as Optishield
©
Plus or equivalent. Avoid
glycol-based additives as they reduce the coolant’s capacity and high concentrations may affect power
stability. For NOVANTA lasers, the minimum coolant set point is 19 °C (66) °F so glycol is not necessary
unless the chiller is subjected to freezing temperatures.
• In applications where biocides containing chlorides are used, concentrations should not exceed
25 parts per million (PPM).
• Maintain a coolant pH level above 7.0. We recommend the installation of a filter on the chiller’s
return line, especially in areas where water hardness is a problem.
The chiller’s temperature setpoint must always be set above the dew point temperature. In cases where
this is not possible within the specified coolant temperature range of 18 °C to 22 °C (64 °F to 72 °F), then
the following steps MUST be taken to reduce the risk of condensation damage.
• Stop coolant flow when the laser is shut down.
• Increase coolant flow by an additional 3.8 LPM (1.0 GPM). Do not exceed a coolant pressure of
414 kPa (60 PSI).
To use the following dew point table, look down the Air Temp column and locate an air temperature in
Fahrenheit or Celsius (°C values are shown in parentheses) that corresponds to the air temperature in
the area where your laser is operating. Follow this row across until you reach a column matching the
relative humidity in your location. The value at the intersection of the Air Temp and Relative Humidity