Synrad 32-1 - Page 43

SYNRAD® 32-1 Operator’s Manual Version 2.2
43
User I/O Connections
Technical Reference
Gated operation
In many marking and cutting applications, the laser is required to pulse, or gate, on and o in
synchronization with an external control signal (typically from a computer or function gen-
erator 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 lev-
el (+3.5 V to +5.0 VDC) signal is applied to the Gate input connector. In the pull-down (normal-
ly o) mode an asserted logic low state, short circuit to ground, or an open or disconnected
Gate input locks the beam o.
Many CO 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 gas) is more ecient than a hotter one. This
overshoot is more pronounced at lower gating frequencies since the gas has a longer time to
cool down between PWM signal pulses.
When operating in CW mode, laser power output cannot be adjusted. If you require
an adjustable output power level, refer to the Pulse width modulation (PWM) sec-
tion for information regarding high frequency operation.
Note:
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.
Warning