Mitsubishi Electric MELSEC iQ-R Series User Manual page 41

Section 4 I/O SIGNALS TO CPU MODULE
(6) Waveform data acquisition clock (Xn6)
The clock is to acquire the waveform data by synchronizing with this module.
This signal (Xn6) detects switching of OFF to ON so that it is able to acquire waveform data by synchronizing.
*When acquiring waveform data per period of measured data acquisition clock, refer to "5.2.12".
(a) Clock operation
After power ON of the CPU module, it starts clock operation with this signal (6) ON immediately after first
computing.
When the setting of phase wire system, primary voltage, primary current primary voltage of VT, secondary
voltage of VT, primary current of CT and period of measured data acquisition clock is changed, it starts
clock operation with the signal immediately after setting change.
Below diagram indicates ON time and OFF time of this signal.
(b) Measured items which update data
Voltage and current
continuous
waveform data
(c) Synchronizing method
Please note as below in order to acquire waveform data by synchronizing with this module.
(i) The program is configured to set the scan time of ladder program will be less than 127μs.
The scan time should be shorter than ON time and OFF time in order to detect "OFF → ON" of the
signal (Xn6).
(ii) Acquire data by detecting "OFF → ON" of the signal (Xn6).
Waveform data is updated immediately before the signal (Xn6) is ON. Since the last value and latest
value are mixed while updating, it is able to acquire waveform data at a timing as below.
T
254μs
Measured items
1-2 voltage waveform data
2-3 voltage waveform data
Phase 1 current waveform data
Phase 3 current waveform data
T T
ON OFF
127μs 127μs
Buffer memory
Un\G22002, 22003
Un\G 22004，22005
Un\G 22008，22009
Un\G 22012，22013
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RE81WH