Measuring The Rotational Speed Or Total Rotations - Omron SYSMAC CJ Series User Manual

7 High-speed Counters
Reading the High-speed Counter Frequency with a PRV(881) Instruction
Execution condition
Precautions for Correct Use Precautions for Correct Use
The frequency measurement function can be used with high-speed counter 0 only.
Specifications
Item
Number of frequency
measurement inputs
Frequency measure-
ment range
Measurement method
Stored data Unit
Output
data range
* If the frequency exceeds the maximum value, the maximum value will be stored.
7-2-6

Measuring the Rotational Speed or Total Rotations

The rotational speed (rotations) or the total number of rotations can be measured.
• Measuring the Rotational Speed
The speed in r/min is calculated from the pulse frequency and the set number of pulses per rotation.
Execute the PRV2(883) instruction and specify converting the frequency to a rotational speed.
• Measuring the Total Rotations
The total number of rotations is calculated from the counter's PV and the set number of pulses per
rotation. Execute the PRV2(883) instruction and specify converting the counter's PV to the total num-
ber of revolutions.
PRV2(883) (PULSE FREQUENCY CONVERT) Instruction
• Measuring the Rotational Speed
Execution condition
7-18
@PRV
P: Port specifier (always high-speed counter input 0)
#0010
C: Control data for reading frequency (10-ms sampling)
#0013
D: First destination word
D100
D100
D101
1 input (high-speed counter 0 only)
Differential phase input: 0 to 50 kHz*
All other input modes: 0 to 100 kHz*
Execution of the PRV(881) instruction
Hz
Differential phase input: 0000 0000 to 0003 0D40 hex
All other input modes: 0000 0000 to 0001 86A0 hex
@PRV2
C1: Control data, Example: Rotational speed r/min,
converting frequency to rotational speed
#0000
#03E8 C2: Pulses per revolution, Example: 1,000 pulses (03E8 hex)
D: First destination word
D100
Conversion result
D100
(lower word)
Conversion result
D101
(upper word)
15 0
Present frequency
data lower bytes
High-speed counter frequency that was read
Present frequency
data upper bytes
Description
Rotational speed that was read (r/min)
CJ2M CPU Unit Pulse I/O Module User's Manual