Frequency Measurement - iDect FC6A series User Manual

Frequency Measurement

This section describes frequency measurement, which measures the frequency of pulses input to an external input. Frequency
measurement is a function that measures the frequency of pulses input to an external input.
These input pulses are processed with dedicated hardware device in FC6A Series MicroSmart, so frequencies can be measured
with no relation to the scan time. The measurement results are stored in special data registers and they are updated with each
scan.
Function Specification
The FC6A Series MicroSmart external inputs are used by switching between normal input, high-speed counters, catch input,
interrupt input, and frequency measurement. To use frequency measurement, specify the relevant group as Frequency
Measurement in the WindLDR Function Area Settings.
Frequency measurement can be used with the following external inputs.
Group
External Input
Frequency
Measurement Value
Frequency
Measurement Range
Measurement Error
Calculation Cycle
*1 Can be used as a normal input.
The frequency measurement results are stored in the following special data registers by external input group. The gate inputs can
also be controlled by special internal relays, so frequency measurements can be started and stopped by turning the gate inputs on
and off.
Group
Gate Input
Frequency Upper Word
Measurement
Lower Word
Value (32 bits)
Notes:
R/W is the abbreviation for read/write. When R/W, it can be read and written. When R, it can only be read. When W, it can only be written.
•
To reflect the measurement results in the special data registers, a maximum of calculation cycle + scan time is required. However, when the
•
FRQRF instruction is used during ladder processing, the frequency value of the special data registers can be updated to the latest value. The
latest calculation result can be read within 250 ms regardless of the input frequency.
The data registers for the upper word and the lower word of the measurement value change according to the 32-bit data storage method
•
specified. For details, see "32-bit Data Storage Setting" on page 5-48.
1
I2 I0
*1
— Yes
4 Hz to 100 kHz
Less than ±10% (4 Hz or higher and less than 4 kHz), less than ±0.1% (4 kHz or higher)
Within 1 s (less than 4 kHz), within 250 ms (4 kHz or higher)
1 2
D8031 D8052
D8210 D8192
D8211 D8193
FC6A S M S A
ERIES ICRO MART
2 3
I1 I3
Yes Yes
4 Hz to 5 kHz
3 4
D8035 D8041
D8218 D8222
D8219 D8223
- -O T U ' M
LL IN NE YPE SER S ANUAL
5: F
UNCTIONS AND
4 5
I4 I5 I6
*1
Yes — Yes
4 Hz to 100 kHz
5 6
D8045 D8060
D8226 D8198
D8227 D8199
FC9Y-B1722
S
ETTINGS
6
I7
Yes
Read/Write
R/W
R
5-35