IDEC MICROSmart FC6A Series, Руководство пользователя

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5: F
UNCTIONS AND
S
ETTINGS
5-40 FC6A S
ERIES
MICROS
MART
U
SER
’
S
M
ANUAL
FC9Y-B1722
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.
The frequency measurement results are stored in the following special data registers for each external input group.
All-in-One CPU module
*1 Can be used as a normal input.
Plus CPU module
*1 Can be used as a normal input.
*2 Can be used only with the Plus 32-I/O type.
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 5-56.
Group 1 2 3 4 5 6
External Input I2 I0 I1 I3 I4 I5 I6 I7
Frequency Measurement
Value
—
*1
Yes Yes Yes Yes —
*1
Yes Yes
Frequency Measurement
Range
4 Hz to 100 kHz 4 Hz to 5 kHz 4 Hz to 100 kHz
Measurement Error Less than ±10% (4 Hz or higher and less than 4 kHz), less than ±0.1% (4 kHz or higher)
Calculation Cycle Within 1 s (less than 4 kHz), within 250 ms (4 kHz or higher)
Frequency
Measurement
Value
(32 bits)
Upper
Word
— D8210 D8192 D8218 D8222 — D8226 D8198
Lower
Word
— D8211 D8193 D8219 D8223 — D8227 D8199
Group 1 2 3 4 5 6
External Input I2 I0 I1 I13
*2
I3 I4 I5 I6 I7
Frequency Measurement
Value
—
*1
Yes Yes —
*1
Yes Yes —
*1
Yes Yes
Frequency Measurement
Range
4 Hz to 100 kHz
Measurement Error Less than ±10% (4 Hz or higher and less than 4 kHz), less than ±0.1% (4 kHz or higher)
Calculation Cycle Within 1 s (less than 4 kHz), within 250 ms (4 kHz or higher)
Frequency
Measurement
Value
(32 bits)
Upper
Word
— D8210 D8192 — D8218 D8222 — D8226 D8198
Lower
Word
— D8211 D8193 — D8219 D8223 — D8227 D8199