Sd Memory Card Life When The Data Logging Function Is Used - Mitsubishi Electric FX5 User Manual
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19.13
SD Memory Card Life When the Data Logging
Function Is Used
An SD memory card has a life (restriction on writing data). The following shows the calculation method of an SD memory card
life when the data logging function is used. Note that the actual life of the card varies depending on usage conditions and
environment. Therefore, use the calculated life as a rough standard for the replacement of the card.
Calculation formula of SD memory card life
SD memory card life (year) = Total size of data that can be written (G bytes) ÷ Size of data to be written per year (G bytes/
year)
Total size of data that can be written
Capacity × Number of writes
For the capacity of applicable SD memory cards and the number of writes, refer to the following.
MELSEC iQ-F FX5U User's Manual (Hardware)
MELSEC iQ-F FX5UC User's Manual (Hardware)
Size of data to be written per year
The size of data to be written per year is obtained by the following formula.
Size of data to be written per year (G bytes/year)= ((DS1
DCN1 + ⋅⋅⋅ + (DCSn*1 + 6144) × DCNn) ÷ 1073741824
*1 Round up DSn and DCSn to a multiple of 512.
DSn, DNn, DCSn, and DCNn are obtained as follows.
■Data logging data size per record (DSn)
Binary file output format: Refer to the data. (Page 455 Binary file output format)
■Number of records for data logging per year (DNn)
Continuous logging: DNn = 60 × 60 × 24 × 365 ÷ Collection interval and timing (seconds)
Trigger logging: DNn = Total number of records
*1 The value that is determined depending on the condition set in "Sampling" when "Continuous logging" is selected for the logging type.
(When the value is determined in milliseconds, convert the value into seconds.)
*2 Calculate the ratio using the operating time per year of the CPU module. For example, if the operating time per year is 5000 hours, the
operating rate is calculated as follows: 5000 ÷ (24 × 365) = 0.57.
*3 The value set in "Number of logging lines" when "Trigger logging" is selected for the logging type.
■Header size of data logging (DCSn)
Binary file output format: Refer to the header. (Page 455 Binary file output format)
■Number of file switching times for the data logging per year (DCNn)
Calculate this number with an estimated number according to the save setting of the data logging and system operations. For
example, when 1000 records are set in "Number of records" of "File switching timing" in the save setting and "Each scanning
cycle" is specified for "Sampling interval" in the sampling setting, the time interval of the file switching is obtained by
multiplying the scan time by 1000. Therefore, the number of file switching times for the data logging per year is obtained by
the following formula: 60 × 60 × 24 × 365 ÷ (Scan time (second) × 1000).
19 DATA LOGGING FUNCTION
144
19.13 SD Memory Card Life When the Data Logging Function Is Used
*1
+ 6144) × DN1 + ⋅⋅⋅ + (DSn*1 + 6144) × DNn + (DCS1*1 + 6144) ×
*3
*1
*2
× Operating rate
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