Gentec-EO MACH 6 - Manual (Page 39)

Mach 6 User’s Manual Revision 2.1 39
a trigger is generated by the instrument. For external triggers, if the TTL trigger occurs
within less than 100ns of the emission of a laser pulse, then the default value will suffice.
If used with external trigger, the timing relationship between the external TTL trigger and
the laser firing event can be accounted for by setting the delay appropriately. The
available range is -932ns to 2863ns. The figure below shows an external trigger pulse and
the analog out from the Mach 6 measured on an oscilloscope.
If the trigger is set to external, with a rising edge polarity, then the temporal relationship
between the rising edge of the trigger trace and the rising edge of the pulse trace must be
known. The figure below is the same as above with the time base expanded and a set of
cursors turned on.
The delay is seen to be approximately 300ns. This will be the trigger delay setting. The
delay to the falling edge of the trigger pulse is -1250ns. Since the range of delay is -932ns
to 2863ns, setting the polarity to falling edge would result in inaccurate measurements.