Omron CP - PROGRAMMING MANUAL 05-2007 Programming Manual page 751

High-speed Counter/Pulse Output Instructions
Flags
Examples
718
At high frequencies (above 1 kHz), the function counts the number of
pulses within a fixed interval (the sampling time) and calculates the fre-
quency from that count. One of the following three sampling times can
be selected by the third digit of C1.
Sampling time Value of C1
10 ms
100 ms
1 s
• Low-frequency counting
At frequencies below 1 kHz, the Standard Calculation Method is used,
regardless of the sampling time setting.
Converting Counter PV to Total Number of Revolutions (C1 = 0001 hex)
If C1 is 0001 hex, PRV2(883) calculates the cumulative number of revolutions
from the counter PV and pulses/revolution setting.
Conversion result = Counter PV
Name Label
Error Flag ER
Overflow Flag OF
Example 1
When CIO 0.01 is ON in the following programming example, PRV2(883)
reads the present pulse frequency at high-speed counter 0, converts that
value to rotation speed (r/min), and outputs the hexadecimal result to D201
and D200.
0.01
Example 2
When CIO 0.01 is ON in the following programming example, PRV2(883)
reads the counter PV, converts that value to number of revolutions, and out-
puts the hexadecimal result to D301 and D300.
0.01
0@10 hex Counts the number of pulses every 10 ms.
The error is 10% max. at 1 kHz.
0@20 hex Counts the number of pulses every 100 ms.
The error is 1% max. at 1 kHz.
0@30 hex Counts the number of pulses every 1 s. The
error is 0.1% max. at 1 kHz.
Pulses/revolution
Operation
ON if high-speed counter 0 is disabled in the settings.
ON if C1 is not in the specified range (0000 or 0001).
ON if the pulses/revolution setting in C2 is 0000.
ON if the maximum value is exceeded for a Y CPU Unit.
PRV2
Converting frequency to rotation speed
#0000
Pulses per revolution
#0003
D200
PRV2
#0001 Converting counter PV to total number of revolutions
#0003 Pulses per revolution
D300
Section 3-20
Description