When saving to the backup memory (SRAM), the amount of space used by the sampling data varies depending on the Number of Sampling Groups, [Enable multiple data types] setting, Data type, Number of Data (Addresses) and the [Mode] tab settings.
Without the sampling settings, the usage capacity is 0 bytes.
The capacity of the backup memory (SRAM) that you can use for sampling data depends on the type of display unit and the space used by other data. For details about backup memory (SRAM), please see the following.
2.3 About the Display Unit's Internal Data
To check the backup memory (SRAM) usage, from the [Project (F)] menu, point to [Information (I)], select [Project Information (I)], and then select [SRAM Information].
Calculation - if [Enable multiple data types] is off
Space Usage for entire system (in bytes)
(4 + 4 x Number of Groups) + each Sampling Group's total usage capacity |
Usage per group (in bytes)
20+ Number of Blocks x Occurrences*1 x {2*2 x Number of Data*3 + 12*4 + (Number of Data + 31)/32 x 4*5} |
*1 When in the [Mode] tab's Extended area the [Overwrite old data after finishing the specified cycles] check box is selected, the value is [Occurrences]+1.
*2 Two bytes when the [Address] tab's [Bit Length] is [16 Bit]. Four bytes when the [Bit Length] is [32 bit].
*3 If the number of data (addresses) is an odd number, add +1 to the value.
*4 When the [Add Time Data] in the [Mode] tab is selected, add 12 bytes for time data.
*5 When the [Add Data Valid/Invalid Flag] in the [Mode] tab is selected, add the defined size (the underlined portion).
Example calculation - if [Enable multiple data types] is off
Setting |
Description |
|---|---|
Number of Groups |
1 |
Data Type |
16 Bit |
Sampling Words |
7 |
Occurrences |
100 |
Blocks |
1 |
Overwrite old data after finishing the specified cycles |
ON |
Add Time Data |
ON |
Add Data Valid/Invalid Flag |
ON |
Calculation
(4 + 4 x Number of Groups) + 20 + Number of Blocks x (Occurences + 1) x {2 x (Number of Data + 1) + 12 + (Number of Data + 31) / 32 x 4}
Calculation result
(4+4x1)+20+1x(100+1)x{2x(7+1)+12+(7+31)/32x4} = 3260 bytes
Calculation - if [Enable multiple data types] is on
Space Usage for entire system (in bytes)
4 + 4 x Number of Groups + Total of each Sampling Group's Usage |
Usage per group (in bytes)
20 + Number of Blocks x Occurrences*1 x {2 x Number of Data*2 + 12*3 + (Number of Data + 31) / 32 x 4*4} |
*1 When in the [Mode] tab's Extended area the [Overwrite old data after finishing the specified cycles] check box is selected, the value is [Occurrences]+1.
*2 Number of Data is the number of rows (words) used. The total size for the data portion (underlined portion in the calculation) is 2 bytes x Number of Rows.
If the total size for the data portion cannot be divided by four, it is displayed to a value divisible by four.
*3 When the [Add Time Data] in the [Mode] tab is selected, add 12 bytes for time data.
*4 When the [Add Data Valid/Invalid Flag] in the [Mode] tab is selected, add the defined size (the underlined portion).
Total Size for the Data Portion
The total size for the data portion is 2 bytes x Number of Rows. The relationship between the Data type and the number of rows used is as follows.
Data Type |
Number of Rows Used |
|---|---|
Bit, Word 8 Bit, Word 16 Bit |
Row 1 |
Word 32 Bit, TIME, DATE, TIME_OF_DAY |
Row 2 |
Text |
1 Rung for 2 characters |
DATE_AND_TIME |
4 Rungs |
Example Calculation - if [Enable multiple data types] is defined
Setting |
Description |
||
|---|---|---|---|
Number of Groups |
1 |
||
Total (Number of Data) |
7 |
||
|
Bit |
#:1 |
1 rows |
Word 16 Bit |
#:1 |
1 rows |
|
Word 32 Bit |
#:1 |
2 rows |
|
Text (16-bit device) |
Number of characters: 5 |
3 rows |
|
Occurrences |
100 |
||
Blocks |
1 |
||
Overwrite old data after finishing the specified cycles |
ON |
||
Add Time Data |
ON |
||
Add Data Valid/Invalid Flag |
ON |
||
Calculation
(4 + 4 x Number of Groups) + [20 + Number of Blocks x (Occurences + 1) x {2 x (Number of Data) + 12 + (Number of Data + 31) / 32 x 4}]
Calculation result
(4+4x1)+20+1x(100+1)x{(2x7+2)+12+(7+31)/32x4} = 3260 bytes
Indication of the number of sampling data you can save
The save area size differs depending on the display unit model. On models with 320 KB backup memory (SRAM), you can save a maximum 163,244 units of data for all sampling groups when you use both backup memory (SRAM) and working memory.
However, when backup memory (SRAM) is used for other features, the capacity for sampling data decreases.
Estimate when you use a display unit with 320 KB of SRAM (using only data sampling)
Condition |
Backup Memory (SRAM) |
Working Memory |
Word data only |
Up to 81,332 |
Up to 81,912 |
Word data + Time data |
Up to 20,332 |
Up to 20,476 |
Word data + Data Valid/Invalid Flag |
Up to 40,664 |
Up to 40,954 |
Word data + Time data + Data Valid/Invalid Flag |
Up to 16,264 |
Up to 16,380 |