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6 Incremental Encoder Input Units
NX-series Position Interface Units User’s Manual (W524)
6-9 Functions
6
6-9-9 External Input Function Selection
You can use the Z phase at the same time for latch input 1, latch input 2, and the reset.
If you use it for both a latch input and the reset, the latch input and reset are input simultane-
ously. In this case, the reset is performed first and then the value is latched.
To use an external input as a gate input, latch input (1 or 2), or reset input, digital filtering is performed
for 20 to 200 μs when the external input turns ON (i.e., when the internal logic is TRUE after applying
the selected logic).
The input latch itself is a hardware latch on the first edge, so any data variation results from the charac-
teristics of the hardware input. However, software processing is applied to the data confirmation pro-
cessing that is performed after that. Therefore, you must set a signal width of at least 200 μs for
external inputs.
For latch and reset operations, digital filtering is determined according to the input that is detected up to
200 μs after the present position input was detected.
Signal Width Greater Than 200 μs
If the signal width is greater than 200 μs, the input is detected when it turns ON and the input is
valid. Therefore, processing is based on the obtained latch data.
Signal Width Less Than the Detected Width
If the signal width is less than the detected width, the input is not detected when it turns ON and the
input is not valid. Therefore, the obtained latch data is discarded and no processing is performed.
Precautions for Correct Use
Digital filtering is performed for 20 to 200 μs for external inputs. Therefore signals with signal
widths of less than 200 μs may not be detected. If you use a sensor with a short response time,
set an OFF delay timer for the output from the sensor or use another method to ensure a signal
width of at least 200 μs for the external input.
Digital Filtering of External Inputs
ON
OFF
External input
20 to 200 µs
Latch data is obtained.
ON
OFF
External input
20 to 200 µs
Latch data is obtained.
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