ACM - Access Control Module(s)
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The Yellow LED drive gets inverted in the read head resulting in a Red LED when the
signal is low and a Green LED when the signal is high. If the Yellow LED drive is
oscillating, the Red and Green LEDs will oscillate and it will appear to the human eye
that the LED is Yellow. The iSTAR Pro will oscillate the Yellow drive at 1 KHz when a
Yellow LED display is required.
3 Wire (Red, Green, Yellow)
When S3-1 is Off and S3-2 is On, it specifies Three wire LED control. In this case, the
Red, Green, and Yellow LED drives are wired to its associated LED of the same color as
shown in Figure 8.
FIGURE 8. Three wire LED control
When S3-1 is On, it specifies One Wire (A,B,C) mode. In this case, a single LED drive
(Red or Green or Yellow) is wired with varying results as shown in Figure 9.
Three Wire LED Control mode is typically used for older read heads that have a single
LED that is either On, Off, or flashing.
