Synrad Firestar f series User Manual

technical reference
39
Synrad Firestar f-Series operator’s manual
Controlling laser power
To generate the correct analog voltage from a computer or PLC, a Digital-to-Analog (D/A or DAC) card
capable of generating 0 V (laser o) to 10 V (maximum laser power) must be installed. To generate the
proper analog current, install a D/A card that can generate 4 mA (laser o) to 20 mA (maximum power).
Software able to control your analog output card is required for either conguration.
Continuous wave (CW)
In some applications, such as high speed marking or cutting, the time constant of the laser and the PWM
modulation causes a series of dots that may be visible on the marking surface instead of a “clean” line.
Operating the laser in CW mode will prevent this behavior from occurring.
To operate the laser in CW mode, apply a constant +5 VDC signal to Pin 9, PWM Input, and Pin 1, PWM
Return, on the User I/O connector. This constant voltage source forces the internal switching electronics
to remain on, providing continuous and uninterrupted laser output power. During CW operation, output
power cannot be changed. To adjust output power, refer back to the Pulse Width Modulation (PWM) sec-
tion for information regarding high frequency operation.
Note: SYNRAD lasers are designed for maximum performance using a 95% duty cycle. Increasing the
maximum PWM percentage beyond 95% greatly increases the laser’s heat load with little or no
corresponding increase in laser output power. Continuous operation at 99% duty cycle may lead
to thermal instability and optical degradation.
Gated operation
In many marking and cutting applications, the laser is required to pulse, or gate, on and o in synchroni-
zation with an external control signal (typically from a computer or function generator operating in the
range from DC to 1 kHz). To pulse or gate the laser, connect a signal providing +5.0 VDC pulses to the
Gate connector on the rear panel of the UC-2000.
Users who intend to use a gating signal should set the UC-2000’s gate input logic to internal Pull-Down
(normally o) mode. This prevents the beam from being enabled unless a high level (+3.5 V to +5.0
VDC) signal is applied to the Gate input connector. In the pull-down (normally o) mode an asserted
logic low state, short circuit to ground, or an open or disconnected Gate input locks the beam o.
Warning
serious
personal
injury
The UC-2000’s default gate logic is factory set to internal Pull-Up
(normally on) mode so that an open (disconnected) Gate input
causes the laser to turn on. This functionality allows the user to easily
test and verify laser operation prior to integration.
In an integrated system, you should congure the UC-2000’s gate
input logic to internal Pull-Down (normally o) mode. This prevents
the beam from being enabled unless a high level (+3.5 V to +5.0
VDC) signal is applied to the Gate input connector. In the Pull-
Down (normally o) mode an asserted logic low signal, short circuit
to ground, or an open or disconnected Gate input locks the beam o.
Many CO
2
lasers operating in applications requiring short gating pulses at repetition rates below 500 Hz
will exhibit some leading edge overshoot regardless of the PWM frequency. This occurs because a cooler
lasing medium (the CO
2
gas) is more ecient than a hotter one. This overshoot eect is more pronounced
at lower gating frequencies since the gas has a longer time to cool down between Command signal pulses.

Synrad Firestar f series Specifications

General

Brand	Synrad
Model	Firestar f series
Category	Measuring Instruments
Language	English