User`s manual

149
CHAPTER 4 FUNCTION
4
4.13 Frequency Measurement Function
● After the start of the frequency measurement, 1
H
: Updated is stored in CH1 Measured frequency value update flag
(Un\G1131) every time the measured value is stored in CH1 Measured frequency value (Un\G1132, Un\G1133).
The value previously stored in CH1 Measured frequency value (Un\G1132, Un\G1133) is hold while 0
H
: Not updated is
being stored in CH1 Measured frequency value update flag (Un\G1131).
● The margin of error (maximum) of the frequency measurement function is calculated from the following formula.
The table below shows the each value to be put into the formula.
The margin of error (maximum) is calculated as shown below.
● CH1 Measured frequency value update flag reset command (Un\G1120) responds within 2ms after the action.
● Do not use CH1 Measured frequency value update flag (Un\G1131) and CH1 Measured frequency value update flag
reset command (Un\G1120) when retrieving CH1 Measured frequency value (Un\G1132, Un\G1133) via the auto refresh
target device. (In case 1
H
: Updated is stored in CH1 Measured frequency value update flag (Un\G1131) after the auto
refresh is done, the updated values are not reflected to the auto refresh target device and therefore, the values retrieved
via the auto refresh target device are the ones before the updating.)
Item Value
Real frequency (Hz) 1234Hz
A unit of time for frequency measurement (s) 0.01s
Number of moving average count for frequency
measurement
2 times
A unit of time for frequency measurement (s)
Number of moving average count for frequency measurement
Real frequency (Hz)
+
100(ppm)
1000000
1
Ex.
1234(Hz) +
= 0.1234(Hz) + 50(Hz)
= 50.1234(Hz)
100(ppm)
0.01(s) 2
1
1000000