Mitsubishi Electric MELSEC-L02SCPU User Manual page 232

(5) Function details
The operation of rotation speed measurement is shown below.
Ex. Operation when the rotation speed measurement unit time is set to "0.1s" and the rotation speed
movement averaging processing count is set to "4"
Rotation speed
Rotation speed measurement
instruction execution condition
CH1 rotation speed
in-measurement
flag (SD1882.b5)
Rotation speed measurement value
No.
Turning on the execution command for Rotation speed measurement instruction (ICRCNT1) starts the following operations:
1) • Measurement of the rotation speed
• CH1 Rotation speed in-measurement flag (SD1882.b5) changes from operation stop(0) to operating(1).
While processing the execution command for Rotation speed measurement instruction (ICRCNT1), a measured rotation speed
2) value is written to the device specified by the Rotation speed measurement instruction (ICRCNT1). As the rotation speed
moving average processing count is set as 4 times, an average of the 4 counts is saved.
Turning off the execution command for Rotation speed measurement instruction (ICRCNT1) starts the following operations:
• Measurement of the rotation speed stops
3) • CH1 Rotation speed in-measurement flag (SD1882.b5) changes from operating (1) to operation stop (0).
• The measured rotation speed value becomes 0. (The rotation speed is not saved to the setting data of Rotation speed
measurement instruction (ICRCNT1).)
230
0.1s
0
ON
1)
OFF
ON
OFF
0
Rotation speed measurement value data transition
1st storage (a)
+ + +
4
0.1s
3)
2)
(a) (b) (c)
2nd storage (b) 3st storage (c)
+ + +
4
Description of operation
1st storage (a)
2nd storage (b)
3st storage (c)
0
+ + +
4
t(s)