Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 897

Processing details
• This instruction counts the number of times the input of the device specified by (s1) turns on for the duration specified by
(s2), and stores the count result in the device specified by (d).
Start of counting
ON
Execution
OFF
command
ON
(s1)
OFF
• Upon completion of measurement, the SPD instruction starts measurement from 0 again. To stop measurement by the SPD
instruction, turn off the execution command.
• If the value specified in (s2) is 0, no processing is performed.
Operation error
There is no operation error.
• The SPD instruction stores the data of the argument device in the work area of the CPU module, and
performs the actual count operation using system interrupts. (The device data stored in the work area of the
CPU module is cleared by turning off the execution command or setting it to STOP then RUN.) For this
reason, the pulses that can be counted must have longer on/off time than the interval of the CPU module.
The interrupt interval of the CPU module is 1ms.
• The SPD instruction can be used a maximum of six times in all running programs. The seventh or
subsequent UDCNT1 instruction, if issued, causes no processing.
• The set value cannot be changed during measurement by the SPD instruction (while the command input is
on). To change the set value, turn off the command input in advance.
(s2)ms
The counting result is stored in (d).
(s2)ms
The counting result is stored in (d).
7 APPLICATION INSTRUCTIONS
7.17 Pulse Related Instructions
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