Xtium2-CL MX4 User's Manual
Declarations of Conformity
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117
Note 3.5: Interfacing to a TTL using a Bias Voltage
RS-422 (-) input
FG/system GND
DC
Bias Voltage
+2V
GND
Frame Grabber System
Interfacing TTL Output to RS-422 Inputs
via a Line Buffer/Driver
TTL signal source & Buffer Driver
(example: 74ACT244)
100 ohm
RS-422 / TTL (+) input
Figure 42: Interfacing TTL to RS-422 Shaft Encoder Inputs using a Bias Voltage
•
If necessary, a TTL input can be connected to the RS-422 / TTL input using a bias voltage
(however it is recommended to use the Shaft Encoder TTL mode described in
. The
graphic shows a single-ended driver signal interfaced to the RS-422 input.
•
RS-422 (-) input is biased to a DC voltage of +2 volts. This guarantees that the TTL signal
connected to the RS-422 / TTL (+) input will be detected as a logic high or low relative to
the (-) input.
•
The TTL shaft encoder ground, the bias voltage ground, and the Xtium2-CXP PX8 computer
system ground must be connected together.
•
DC voltage for the RS-422 (-) input can be generated by a resister voltage divider.
•
Use a single battery cell if this is more suitable to your system.
•
NOTE: User must select the Shaft Encoder RS-422 level when using this mode
(
CORACQ_PRM_SHAFT_ENCODER_LEVEL
= CORACQ_VAL_LEVEL_422 (0x2)
).
