Mitsubishi Electric QD62, User Manual

Page: 69 / 128

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MELSEC-Q
6 CONVENIENT USAGE
6.1.2 Count error
With the counter function selection, an error occurs in the count when it is executed
using an external input (voltage applied to the function start input terminal) or by a
sequence program (counter function selection start command ON).
The following explains how to calculate the count error.
(1) Count error (maximum) due to input response delay when using an
external input
1000
[s]
1 [ms]
pulse input speed [PPS] multiple [count]
(2) Count error (maximum) when the counter function selection is
executed by a sequence program
1000
[s]
1 scan time [ms]
pulse input speed [PPS] multiple [count]
(3) Count error (maximum) due to the internal clock when executing
the sampling counter function and periodic pulse counter function
1000000
1000
[s]
1000000
Sampling/cycle time setting value x 10 [ms] Error in parts dimensions, 100 [ppm]
Pulse input speed [pps] Multiplier factor [count]
(Sampling/cycle time setting value (unit: 10ms)) Pulse input speed [pps] Multiplier factor [count]