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CV-M2

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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 illumination. The
first accumulation time is fixed at 4 µsec. After a delay >1.5 µsec. 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

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.
•  A new trigger must not be applied before FVAL is low after second frame readout.
•  1LVAL = 47.9 µsec (single). 27.3 µsec (dual).

For horizontal timing refer to 6.2.3. through 6.2.6. (Fig.17. through fig. 20.)

For LVAL a-synchronous accumulation refer to 6.2.8. (fig. 22.)

LVAL

DATA OUT

SUB

FVAL

EEN

Ext . Tr i g1

Second Fr ame

4us( 1/ 250, 000s)

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. 28. PIV mode

LVAL

FVAL

SUB

104ck

Exposur e

Per i od

52ck

40ck( 1us)

120ck( 3us)

Ext . Tr i g

Exposur e del ay:

156ck( 3. 9us)

Fi r st exposur e t i me:

160ck( 4us)

EEN

60ck( 1. 5us)

Fig. 28A. PIV mode details