Count Error - Mitsubishi Electric RD62P2E Application User's Manual

Count error

A count error may occur when the selected counter function is performed using an external input (A voltage is applied to the
function start input terminal) or using a program (CH1 Counter function selection start command (Y6) is turned on). The
following describes how to calculate the count error.
Count error (max.) when an external input is used
Due to a delay in the input response time of the function start input terminal, the following error occurs.
A
Count error
= [s] × B
(maximum)
1000
A Function input response time setting [ms] (1ms maximum)
Pulse input speed [pps] (= Pulse input frequency [Hz]  Multiplication [count])
B
Count error (max.) when a program is used
Due to a delay in the scan time of the program (Delay of turning on CH1 Counter function selection start command (Y6)), the
following error occurs.
A
Count error
= [s] × B
(maximum)
1000
A 1 scan time [ms]
Pulse input speed [pps] (= Pulse input frequency [Hz]  Multiplication [count])
B
Count error (max.) on the sampling counter function or cycle pulse counter function
A sampling/cycle time error occurs due to an error in design (100ppm) when the sampling counter function or cycle pulse
counter function is performed. The count error is calculated as follows:
A B
Count error
= [s] ×
(maximum)
1000 1000000
A Sampling/cycle time [ms]
B 100 [ppm]
Pulse input speed [pps] (= Pulse input frequency [Hz]  Multiplication [count])
C
× C
1 FUNCTIONS
1.5 Counter Function Selection
1
27