National Instruments ISC-1762, Руководство пользователя

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Chapter 4 Lighting
Figure 4-2 illustrates how to connect a light to the Direct Drive lighting controller. Do
not
use
the GND signal when connecting a light to the Direct Drive lighting controller.
Figure 4-2. Connecting a Light to the Direct Drive Lighting Controller
The Direct Drive controller performs an initialization sequence to achieve the requested current
output prior to acquiring the first image. You may notice a sequence of short flashes from the
light when the application initializes or shuts down.
External Lighting Controllers
While the Direct Drive lighting controller is designed to handle common machine vision lighting
requirements, some applications require the use of a light with current or voltage requirements
beyond those supported by the Direct Drive. Other applications require more than one light. All
NI Smart Cameras support connections to third-party lighting controllers to solve these
applications.
The smart camera provides two types of external lighting outputs for synchronizing third-party
controllers to the exposure of the smart camera: a 5 V TTL strobe output and a 24 V strobe
output. The 5 V TTL strobe output is available for connecting to devices that require a 5 V signal.
The 24 V strobe output is powered by the voltage from the smart camera power supply and is
available for controllers that require higher voltage inputs. The 24 V strobe output is nominally
a 24 V output if 24 V power is supplied to the smart camera.
Caution The 24 V external lighting strobe is an unregulated output dependent on
the range of the power supply provided to the smart camera. If the power provided to
the smart camera is +20%/-15% with +5% AC ripple, the output could be as high as
30 V. If the provided power exceeds the input voltage specifications of the third-party
lighting controller, do
not
connect the 24 V lighting strobe output to the controller to
prevent damage to the controller. Use a power supply with tolerances that meet the
requirements of the controller, or use the 5 V external lighting strobe.
When enabled, the 5 V and 24 V external strobe outputs create a strobe pulse that can be used
as a level-sensitive signal by third-party controllers to strobe the light simultaneously with the
image exposure. Alternatively, if the third-party lighting controller supports a programmable
LED–
LED+
LED
NI 17xx
Direct
Drive