8-4
Number of Samplings Setting
8-4-1
Function Applications and Overview
This function sets the number of samplings of analog input data to obtain.
The sampling period is determined by the task period of the assigned periodic task and the number of
samplings per period.
8-4-2
Details on the Function
The function sets the number of samplings per period for analog input data.
Here, the period means the task period of an assigned periodic task.
Task period of assigned periodic task
*1
Task period of assigned periodic task
*1
Sampling period
2 N
1
2 N
1
1
Sampling period
N: Number of samplings [times]
*1. The primary periodic task or the priority-5 periodic task should be assigned. If any other periodic task is as-
signed, the Unit does not perform sampling correctly.
The sampling period for each channel is determined by the task period of the assigned periodic task
and the number of samplings per task period. The calculation formula for a Unit to which the High-
speed Analog I/O Unit is connected to is as follows:
Ch£
Sampling Period [µs]
=
Task period of assigned periodic task [µs] ÷ Ch£ Number of Samplings [times]
For example, when the task period of an assigned periodic task is set to 1 ms and the number of sam-
plings is set to 100, the sampling period can be calculated as follows:
•
Sampling period = 1000 µs ÷ 100 times = 10 µs
Precautions for Correct Use
When you use an NX-series High-speed Analog Input Unit in the CPU Rack or Slave Terminal,
the primary periodic task or the priority-5 periodic task should be assigned. If any other periodic
task is assigned, the Unit does not perform sampling correctly.
Set the number of samplings in the Unit operation settings. The settings are shown in the following
table.
8 Functions
8 - 8
NX-series Analog I/O Units User’s Manual for High-speed Analog Input Units (W592)
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