Sd Memory Card Life When The Data Logging Function Is Used - Mitsubishi MELSEC Q series User Manual

6.8
SD Memory Card Life When the Data Logging Function
is Used
Each SD memory card has its limit on writing data. This section describes how to calculate the life of an SD memory
card when the data logging function is used. Use the calculated limit for reference since the actual life of the card
varies depending on the use conditions and environment.
(1) Calculation formula
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)
(2) Total size of data that can be written
Capacity  Number of writes
*1 For the capacity of applicable SD memory cards and the number of writes, refer to the following.
User's Manual (Hardware Design, Maintenance and Inspection) for the CPU module used
(3) 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
*1
+ 6144)  DCN1 +  + (DCSn
(DCS1
*1 Round up DSn and DCSn to a multiple of 512.
DSn, DNn, DCSn, and DCNn are obtained as follows:
(a) Data logging data size per record (DSn)
CSV file output format: Refer to (5) in the following section. ( Page 37, Section 3.3.2)
(b) Number of records for data logging per year (DNn)
• Continuous logging: DNn = 60  60  24  365  Collection interval and timing (seconds)
*2
rate
• Trigger logging: DNn = Total number of records
• Specification period logging: DNn = 60  60  24  365  Collection interval and timing (seconds)
Specification period logging operating rate
*1 A 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 according to the operating time of the CPU module per year. For example, if the operating time per
year is 5000 hours, the operating rate is 0.57 (5000  (24  365)).
*3 A value set in "No. of records" when "Trigger logging" is selected for the logging type
*4 Calculate the operating rate according to the total time during which the conditions of the specification period are met on
the CPU module per year. For example, if the total time of the specification period per year is 2500 hours, the operating
rate is 0.28 (2500  (24  365)).
(c) Header size of data logging (DCSn)
CSV file output format: Refer to "File information line" to "Data name line" in the following section. ( Page
37, Section 3.3.2)
*1
+ 6144)  DN1 +  + (DSn
*1
+ 6144)  DCNn)  1073741824
*3
*4
CHAPTER 6 DATA LOGGING FUNCTION
*1
+ 6144)  DNn +
*1
 Operating
6
*1

71