Gentec-EO MACH 6 - Manual (Page 12)

Mach 6 User’s Manual Revision 2.1 12
Trigger Polarity
Sets the trigger edge polarity for the external trigger pulse. Positive triggers on the rising
edge of the trigger pulse, negative triggers on the falling edge of the trigger pulse.
Trigger Delay
This is the delay of the trigger pulse. If used with external trigger, the timing relationship
between the external trigger pulse and the laser firing event can be accounted for by
setting the delay appropriately. The range is -938ns to +2480ns.
Trigger Hold off
This is the hold off in microseconds for the trigger event. After a trigger event the
instrument will not trigger again until the hold off expires. This is useful for bursts of
pulses at a given rep rate. Supposed there are bursts of 5 pulses occurring every 10us and
the bursts themselves occur every 200us. Setting to hold off to 50us will cause only the
first pulse in the 5 pulse burst to be measured.
Setting the trigger hold off to zero disables trigger hold off.
Arm
Arms the instrument for a data gathering run. Arming the instrument clears any existing
data from the pulse memory, and then enables trigger detection in the processor. As each
pulse is measured, the result is stored in pulse memory, up to 4 million pulses.
(4,194,304) When the pulse memory is full, measurement continues but the data is
discarded. Note that arming the instrument disables all other controls on the application
that communicate with the instrument. This is done to prevent the instrument from losing
pulse data while responding to commands or queries.
Read Pulse Memory
This control calls a user prompt that asks for the pulse offset and the number of pulses to
retrieve from pulse storage memory. Once that information is acquired, the pulse memory
is read. The destination of the pulse memory is dependant on the state of the Read to File
and Read to Display check boxes.
The pulse memory is capable of storing up to 4,194,303 pulses. This is a large volume of
data and it can be time consuming to retrieve all of it at once. The pulse offset and
number of pulses to retrieve controls make this manageable. As an example, suppose
there are 2 million pulses in the memory. The user can ask for this data in batches of
500,000 pulses at a time in 4 batches:
Read 1, pulse offset = 1, number of pulses to retrieve = 500,000