CV-M2CL and CV-M8CL
6.4.6. PIV mode
PIV mode (Particle Image Velocimetry) can be used in applications where 2 images should be
taken with a very short time interval. It can only be used with strobe flash as the only
illumination. The first accumulation time is fixed at 4.68
µ
sec. After a delay >1.5
µ
sec. the
second exposure period starts. It is as long as the time for a full frame. The accumulation is
LVAL a-synchronous. The first exposure period starts at the trigger leading edge. The first strobe
flash should be fired within the first exposure period, and the second strobe flash during the
first frame read out period. The result will then be 2 frames exposed with the flash interval.
To use this mode:
Set function:
Trigger mode “PIV”
TR=5
LVAL synchronous accumulation to “asynch”
LS=1
Scanning format
SC=0 through SC=4
Output select
OS=0, OS=1
Polarity and other functions
Input:
Ext. trigger to Camera Link or pin 10 on 12-pin connector.
2 strobe flash.
Important notes on using this mode.
•
The duration of the trigger should be >2LVAL to <3FVAL.
•
Minimum trigger interval is 2 FVAL + 2 LVAL
•
A new trigger must not be applied before FVAL is low after second frame readout.
•
1LVAL = 47.9
µ
sec (single). 27.3
µ
sec (dual).
•
For minimum trigger delay and jitter, it is recommended to use CL trigger input.
For horizontal timing refer to 6.2.3. through 6.2.6. (Fig.16. through fig. 19.)
For LVAL a-synchronous accumulation refer to 6.2.8. (fig. 22 and 23.)
LVAL
DVAL
DATA OUT
SUB
SG
FVAL
EEN
Ext . Tr i g1
Second Fr ame
4. 68us( 1/213. 675s)
Fi r st Exposur e Per i od
1 f r ame r ead-out per i od
Second Exposur e Per i od
Fi r st Fr ame
Readout del ay:
1 t o 2L
Mi n. : 2L
Fig. 30. PIV mode
LVAL
FVAL
SUB
SG
114ck
Ex pos ur e
Per i od
37ck
81ck ( 2. 042us )
106ck ( 2. 64us )
Ex t . Tr i g
Ex pos ur e del a y :
151ck ( 3. 76us )
Fi r s t ex pos ur e t i me:
187ck ( 4. 68us )
EEN
61ck ( 1. 524us )
Fig. 31. PIV mode details
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