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Figure 4-4 PWM Command signal waveform
I401 User I/O PWM input consists of a high-speed opt isolator LED with a forward voltage drop (Vf) of
1.5 VDC. The PWM input frequency can range from DC (0 Hz) to 100 kHz. Table 3-2 on the following
page provides minimum, maximum, and nominal PWM signal specifications.
Controlling laser power
Table 4-2 PWM Command signal specifications
Laser State
Minimum
Nominal
Maximum
Laser Off
0.0 VDC
0.0 VDC
+0.8 VDC
Laser On
+3.5 VDC (3 mA)
+5.0 VDC
+6.7 VDC (10 mA), continuous
Frequency Range
0 Hz (DC)
5 kHz
100 kHz
Duty Cycle
1%
----
100%
Operating modes
External control
In addition to controlling the i401 laser using a UC-2000 Controller, control of the i401 externally, without
a UC-2000, is also possible. The two primary elements of laser control are gating, the ability to turn the
laser on and off at the appropriate times, and power, the ability to control the laser’s output energy. Both
gating and power can be handled by a device such as a personal computer, Programmable Logic
Controller (PLC), or function generator capable of sending PWM pulses at the proper time (gating) and
with the proper duty cycle (power).
Analog voltage or current control
Although i401 lasers cannot be controlled directly by analog voltage or current signals, this type of
control is possible when using the UC-2000 Controller. The Controller is connected normally to the laser
