FP-DIO-550 and cFP-DIO-550
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Input Latching
In MAX, you can configure each input channel to operate in either
standard mode or latch mode. In standard mode, the channel
returns a value of TRUE when the input is high and FALSE when
the input is low. In latch mode, the channel latches to one value
when it detects a specific input signal state and retains that value
until you reset the channel. The two latch modes are Latch TRUE
on high and Latch FALSE on low. If the channel is in Latch TRUE
on high mode, it returns TRUE when it detects a high input signal
and continues to return TRUE until the channel is reset, regardless
of subsequent changes to the input signal. If the channel is in Latch
FALSE on low mode, it returns FALSE when it detects a low input
signal and continues to return FALSE until the channel is reset. To
unlatch and reset the channel, send the Reset Latch command.
Note
If the input signal matches the value that the
channel is configured to detect when you put the
channel in one of the latch modes, the channel latches
immediately. Similarly, if you attempt to reset the
channel when the input signal is in the state that the
channel is set to detect, the channel will not reset.
You can use input latching to detect short signal pulses that
software polling might otherwise miss.
Connecting a Differential-Output Device
to the [c]FP-DIO-550
You can connect a differential-output device to an input channel of
the [c]FP-DIO-550. Connect the positive lead to the IN+ terminal
of the channel and connect the negative lead to the IN– terminal of
the channel. Refer to Figure 4.
Figure 4.
Connecting a Differential-Output Device
to One Channel of the [c]FP-DIO-550
IN–
IN+
Input
Circuitry
Differential
Output
Device
V
C
+
–
[c]FP-DIO-550
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