NAC Image Technology ST-839, Руководство пользователя

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External input/output signal circuit
External input/output signal circuit
9-47
(00400)
■ TRIG1
Input Equivalence Circuit Diagram
Isolated 5V
Isolated GND
Internal Vdd
Internal GND
100 Ω
4700
Ω
HCT14
TRIG1
0.01
μ
F
Isolation, TTL level, 5 Ｖ pull-up resistance4700 Ω , Ｌ level ：－ 0.5V(minimum applied voltage) ～ 0.8V, Ｈ
level ： 2V ～ 5.5V(maximum applied voltage), trigger enabled for Ｈ→Ｌ , contact point input possible,
polarity reverse function
Recommended Interface Circuit
5V
GND
TRIG1
TTL
SWITCH
TRIG1
Trigger Filter
There is a noise filter circuit included in the digital method which is used to enhance the effect of the
filter by setting the filter value higher when there is significant external noise.
The filter value units are
μ s, and indicate the delay when good pulses without chattering are input. The
minimum setting unit is 0.1 μ s. The factory setting is 20.0 μ s and the range of possible settings is 0.0 ～
6553.5 μ s.
This filter value can be set independently to two trigger inputs.
However, with TRIG1 input, there is a delay of about 1.4
μ s added due to the analog filter on the input part.
It is operated by a contact point or open collector, and if the trigger polarity is straight, the delay of
about 1.4
μ s increases to about 30 μ s.