Chapter 6
Image Acquisition
©
National Instruments Corporation
6-3
NI 177x Smart Camera User Manual
External Trigger
Use the trigger input to synchronize the NI 177x Smart Camera with an
external event, such as the assertion of a signal generated by a proximity
sensor. You can trigger the NI 177x Smart Camera at rates up to the
maximum frame rate. Refer to the
section for
information about factors that affect the maximum frame rate.
To use an external trigger, the trigger signal must be provided on the
and TRIG_IN– inputs to the camera and triggering must be
enabled in the software. Refer to the
Connecting to a Triggering Device
section of Chapter 4,
Connecting Lighting and External Devices
, for
information about connecting external signals.
You can enable triggering in the following software programs:
•
Vision Builder AI
—Select the
Enable Trigger
checkbox on the
Trigger
tab of the
Acquire Image (Smart Camera)
step.
•
LabVIEW
—Set the value of the
TriggerSource
attribute to
External
Trigger
and set the value of the
TriggerMode
attribute to
On
.
•
MAX
—Select the
Enable Trigger
checkbox on the
Triggering
tab of
the device configuration page.
Figure 6-1 illustrates the relationship between an external trigger, a lighting
strobe, and the exposure time.
Figure 6-1.
Externally Triggered Mode
1
User-Configura
b
le Trigger Delay
2
Lighting Turn-On Time
3
Beginning of Image Readout
Trigger
Lighting
S
trobe
Expo
su
re
Im
a
ge Re
a
do
u
t
3
2
1
