Photon Focus CameraLink MV1-D1312 series, User Manual

Page: 53 / 119

The trigger pulse from the internal camera control starts also the strobe control state
machines. The strobe can be delayed by t
strobe − delay
with an internal counter which can be
controlled by the customer via software settings. The strobe offset delay t
strobe
−
delay
results
then from the synchronous design of the FPGA state machines. A second counter determines
the strobe duration t
strobe
−
duration
(strobe-duration). For a robust system design the strobe
output is also isolated from the camera electronic which leads to an additional delay of
t
d − iso − output
. Table 4.10, Table 4.11, Table 4.12 and Table 4.13 gives an overview over the
minimum and maximum values of the parameters.
External Trigger with Pulsewidth controlled Exposure Time
In the external trigger mode with Pulsewidth controlled exposure time the rising edge of the
trigger pulse starts the camera states machine, which controls the sensor. The falling edge of
the trigger pulse stops the image acquisition. Additionally the optional external strobe output
is controlled by the rising edge of the trigger pulse. Timing diagram Fig. 4.35 shows the
detailed timing for the external trigger mode with pulse width controlled exposure time.
e x t e r n a l t r i g g e r p u l s e i n p u t
t r i g g e r a f t e r i s o l a t o r
t r i g g e r p u l s e r i s i n g e d g e c a m e r a c o n t r o l
d e l a y e d t r i g g e r r i s i n g e d g e f o r s h u t t e r s e t
i n t e r n a l s h u t t e r c o n t r o l
d e l a y e d t r i g g e r f o r s t r o b e c o n t r o l
i n t e r n a l s t r o b e c o n t r o l
e x t e r n a l s t r o b e p u l s e o u t p u t
t
d - i s o - i n p u t
t
j i t t e r
t
t r i g g e r - d e l a y
t
e x p o s u r e
t
s t r o b e - d e l a y
t
d - i s o - o u t p u t
t
s t r o b e - d u r a t i o n
t r i g g e r p u l s e f a l l i n g e d g e c a m e r a c o n t r o l
d e l a y e d t r i g g e r f a l l i n g e d g e s h u t t e r r e s e t
t
j i t t e r
t
t r i g g e r - d e l a y
t
e x p o s u r e
t
t r i g g e r - o f f s e t
t
s t r o b e - o f f s e t
Figure 4.35: Timing diagram for the Pulsewidth controlled exposure time
The timing of the rising edge of the trigger pulse until to the start of exposure and strobe is
equal to the timing of the camera controlled exposure time (see Section 4.4.3). In this mode
however the end of the exposure is controlled by the falling edge of the trigger Pulsewidth:
The falling edge of the trigger pulse is delayed by the time t
d
−
iso
−
input
which is results from the
signal isolator. This signal is clocked into the FPGA which leads to a jitter of t
jitter
. The pulse is
4.4 Trigger and Strobe 51