Mitsubishi Electric MELSEC iQ-R User Manual page 77

Number of logging data
With 'CH1 Number of logging data' (Un\G440, Un\G441), the number of valid data points in Logging data area (Un\G10000 to
Un\G99999) can be checked.
When the number of collected data points is less than the
number of points (N) set in 'CH1 Logging data points setting'
(Un\G536)
Address 0
Address 1
(1)
Address 2
Address 3
Address 4
Address 5
(2)
Address N-2
Address N-1
(1) Valid data (CH1 Number of logging data = 5)
(2) Invalid data (The content of the data is not guaranteed.)
(3) Valid data (CH1 Number of logging data = N)
The number of logging data points increases by one every time new data is stored.
When the logging data area distributed to each channel is filled, the next data is stored in the start address of Logging data
area. The logging operation continues overwriting the existing data. In this case, the number of logging data points is fixed to
the number of points set in 'CH1 Logging data points setting' (Un\G536).
Head pointer and latest pointer
The storage locations of the oldest data and the latest data of each channel in Logging data area (Un\G10000 to Un\G99999)
can be checked with the following buffer memory areas.
Buffer memory area
'CH1 Head pointer' (Un\G436, Un\G437)
'CH1 Latest pointer' (Un\G438, Un\G439)
When the number of collected data points is less than the
number of points (N) set in 'CH1 Logging data points setting'
(Un\G536)
(1)
Address 0
Address 1
Address 2
Address 3
(2)
Address 4
Address 5
Address N-2
Address N-1
(1) Storage location of the oldest data CH1 Head pointer = 0
(2) Storage location of the latest data CH1 Latest pointer = 4
(3) Storage location of the oldest data CH1 Head pointer = 5
'CH1 Head pointer' (Un\G436, Un\G437) does not change (fixed to 0) until logging data for the number of the points set in
'CH1 Logging data points setting' (Un\G536) is completed after the logging start.
'CH1 Head pointer' (Un\G436, Un\G437) changes by one point when logging data for the number of the points set in 'CH1
Logging data points setting' (Un\G536) is completed and overwriting the data starts from the start address of Logging data
area (Un\G10000 to Un\G99999).
When the number of collected data points reaches the number
of points (N) set in 'CH1 Logging data points setting' (Un\G536)
Address 0
Address 1
Address 2
Address 3
Address 4
Address 5
Address N-2
Address N-1
Description
Out of the logging data area distributed to each channel, the buffer memory address of the oldest
data can be checked with this buffer memory area. The offset value counted from the start address
of each channel is stored.
Out of the logging data area distributed to each channel, the buffer memory address of the latest
data can be checked with this buffer memory area. The offset value counted from the start address
of each channel is stored.
When the number of collected data points reaches the number
of points (N) set in 'CH1 Logging data points setting' (Un\G536)
(2)
(3)
(3)
Address 0
Address 1
Address 2
Address 3
Address 4
Address 5
Address N-2
Address N-1
1 FUNCTIONS
1.14 Normal Logging Function
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