SCC-DI01 Isolated Digital Input Module User Guide
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Theory of Operation
Power-Up Condition
At power-up, the SCC-DI01 registers a logic low if there are no
connections to the inputs.
Status LED
The SCC-DI01 has a status LED that indicates when an input signal
registers a logic high or a logic low. The LED is located above the screw
terminals. If the LED is off, the input signal is registering a logic low on the
digital line. If the LED is on, the input signal is registering a logic high on
the digital line.
Sensing DC Voltages
The SCC-DI01 registers a logic high when a positive or negative
DC voltage of 2 V or more exists across the screw terminals. If no
voltage is present, the SCC-DI01 registers a logic low.
Sensing AC Voltages
The SCC-DI01 registers a logic high when an AC voltage exists across the
screw terminals. Signals with low amplitude and low frequency cause the
SCC-DI01 to register alternating logic highs and logic lows. Sinusoidal
signals of 1 kHz or higher frequency and 4 V
rms
or higher amplitude cause
the SCC-DI01 to register a constant logic high.
12
—
13
—
14
—
15
—
16
—
17
—
18
—
19
—
20
—
Table 1.
SCC-DI01 Module Pin Assignments (Continued)
Pin Number
Signal Name
