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10
7
General Description
The VTR1 current controller provides repeatable intensity and timing control for strobe lighting.
Two modes of operation are provided for the light output:
Pulse (Strobe):
In pulse mode output is pulsed once per trigger. One trigger input is used as a trigger. The
delay from trigger to pulse, the pulse duration and the brightness can be set.
Switched:
In switched mode a trigger input can be used to switch the output current on and off. The
sense of the trigger signal can be active high or active low.
The set up is non-volatile, so the VTR1 will resume the same operation after a power cycle.
7.1.1
Pulse and Duty Cycle Limits
In both pulsed and switched modes, the pulse width and duty cycle are internally limited to
prevent damage to the light.
The brightness can be set up to 100%, but only for short periods and at low duty cycles, so that
the lighting does not overheat and get damaged. In pulse mode, the duty cycle is limited by
ignoring triggers which are too soon after the previous trigger.
Allowed Pulse
Output
Width for 850nm
Brightness
and 940nm lights
0 to 20%
3ms
21 to 30%
3ms
31% to 50%
3ms
51% to 100%
1ms
So for example, if the brightness is set to 40%, then a VTR1-850 will not allow pulses greater
than 3ms long. With 1ms pulses, if a trigger occurs within 33ms of a previous trigger (so that the
duty cycle would be greater than 3%) the trigger is ignored.
If necessary the VTR1 will limit the duty cycle by increasing the retrigger delay.
When the VTR1 internal temperature gets too high, the allowed duty cycle is reduced and
event 149 is generated. This typically happens at 60
Allowed Duty
Allowed Pulse
Cycle for 850nm
Width for white
and 940nm lights
and 740nm lights
6%
3ms
6%
2ms
3%
2ms
2%
1ms
o
C.
Allowed Duty
Cycle for white
and 740nm lights
3%
3%
2%
1%
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