Digital Output; Static Digital Output Update; Pwm Lighting Output Control - Advantech AIIS-1882 User Manual

4-channel pwm lighting controller module for aiis vision system

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3.2

Digital Output

The AIIS-1882 has digital output function. The following sections describe the digital

output update/generation mechanism. For detailed specification of the functions.

refer to Appendix A.

3.2.1

With static digital output update, the digital output state is updated only when the soft-

ware sends a "write static digital output sample" command. The digital output state

remains unchanged at other times. This is shown in Figure 3.19.

3.3

The lighting control leverages a PWM (Pulse Width Modulation) mechanism. A pulse

waveform with specified high period (tHIGH) and low period (tLOW) is output at

counter output terminal as shown in Figure 3-6.

The lighting intensity is controlled by PWM high period. For example, in the same

PWM cycle period 100ms, setting 100ms as high drives the lighting to maximum

intensity, 0ms on the other hand, turns the lighting off. Figure 3-7 describes the rela-

tion between duty cycle and lighting intensity percentage. With duty cycle of 25%, the

ON period is 25% of the PWM cycle, that results in 25% lighting intensity. It is the

same way when the duty cycle is set to 50% or 75%.

AIIS-1882 User Manual

Figure 3.7 Static digital output update.

Figure 3.8 Pulse width modulation output.

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