MIRcat OPERATION
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output is software controlled by the motion board and will vary, but will generally be in the 100 to several
hundred-microsecond range. The actual laser pulse and trigger output (BNC) will be HI for the pulse width
specified in the settings screen.
Pin
Signal description (cont.)
4 Process trigger: HI when the laser has performed a favorite scan or other process
Active LO Input. This signal is used when “Use External Step Mode” is selected in “Process Trigger
Modes”. In either Step & Measure or Multi-Spectral Mode, the laser will move to the first wavelength and
turn on. It will then stay at that wavelength and continue to fire the laser until this signal is pulled LO. The
signal should be pulled LO to ground for between 250 and 500 ms, at which point the laser will move to the
next wavelength and then start firing.
5 Laser Output On/Off
Active LO Input.
6 Interlock: Ext control of system interlock
Provides status of the interlock signal
7, 9 GND
8
Control Pin, On/Off
TTL signal to turn the laser on and off remotely.
The signals “Tuned”, “Scan Direction”, and any “Trigger” can be used to synchronize the data acquisition
with a Data Acquisition System. The scan mode can be set-up thru the computer controlled GUI commands.
The “Tuned” and “Scan Direction” signals are internally supplied output signals. For Sweep Scan mode,
once a laser wavelength scan range is set, a rising edge on the “Tuned” signal will signal the laser is
scanning across the Start Wavelength, and the falling edge corresponds to scanning across the Stop
Wavelength.
For Step Scan mode, the “Scan Direction” signal goes Hi during the time the laser is performing the step
scan, from the time the laser stops on the Start Wavelength, until the laser finishes the last step and pause
on the Stop Wavelength. The “Tuned” signal will go Hi once the laser has stopped scanning and is ready for
a data point to be taken. It should be noted that once a Step Scan is initiated, the laser will tune to the Start
Wavelength, set the “Scan Direction” signal Hi and set the “Tuned” Signal Hi. This means that for a scan of
one wavenumber, with 0.5 cm-1 steps, the Tuned will go Hi three times. See Laser Scan> Step section for
further details.
A rising edge on the “Scan Direction” signal tells the data acquisition system in which direction the laser is
scanning. A TTL Hi denotes the laser is scanning up in wavelength/wave number. This signal is
operational during the Sweep Scan and the Step Scan function. In pulsed mode, the laser outputs an optical
pulse on the rising edge of each “trigger” signal. This corresponds to the set Pulse Width and Pulse
Repetition Frequency. Using rear panel commands, optical trigger delays can be implemented to fine tune
the data acquisition system.
