20.15 Space Requirements for Alarm History Data
The space on the backup SRAM required for saving the Alarm History data depends on the type of display unit and the number of [Records] of all blocks, the number of registered messages (addresses) and the [Alarm Type] settings.
When no message is registered, the data size is 0 bytes, regardless of the [Backup History] setting.
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When the [Alarm Type] is [Extended], the accumulated time and number of occurrences are not saved in backup SRAM.
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When using GP-4100 series, the frequency at which alarm history data is saved to virtual backup memory is defined in the [Common Settings] menu's [Alarm] editor, [Storage Frequency] field.
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The capacity of the backup memory (SRAM) or virtual backup memory that can be used for Alarm History 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
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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].
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When [Read Data From Each Alarm] is not selected (i.e., when [Number of Address] is zero), the underlined portions in the following calculations become 0 byte.
Calculation 1
If you are using the GP4000 series (except for the GP-4100 series), LT4000 series, or IPC series, use the following calculation.
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1104
+ Number of Blocks for Block 1 x { 44 + 4 + (Number of Addresses + 15)/16 x 4 + Number of Addresses x 4 }
+ (Apply the same calculation as Block 1 for Blocks 2 to 8)
+ (4 x Number of registered messages) + (16 x Number of registered messages) + (4 x Number of registered messages)]
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1104
+ Number of Blocks for Block 1 x { 44 + 4 + (Number of Addresses + 15)/16 x 4 + Number of Addresses x 4 }
+ (Apply the same calculation as Block 1 for Blocks 2 to 8)
+(Block 1 registered message number) + 31)/32 x 4
+ (Apply the same calculation as Block 1 for Blocks 2 to 8)
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Calculation 2
If you are using the GP3000 series, GP-4100 series, LT3000 series, or ST3000, use the following calculation.
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576
+ Number of Blocks for Block 1 x { 28 + 4 + (Number of Addresses + 15)/16 x 4 + Number of Addresses x 4 }
+ (Apply the same calculation as Block 1 for Blocks 2 to 8)
+ (4 x Number of registered messages) + (16 x Number of registered messages) + (4 x Number of registered messages)]
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576
+ Number of Blocks for Block 1 x { 28 + 4 + (Number of Addresses + 15)/16 x 4 + Number of Addresses x 4 }
+ (Apply the same calculation as Block 1 for Blocks 2 to 8)
+(Block 1 registered message number) + 31)/32 x 4
+ (Apply the same calculation as Block 1 for Blocks 2 to 8)
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Calculation Examples
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Setting
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Description
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Backup Alarm History
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Set
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Setting for Block 1
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—
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Number of Records for Block 1
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768
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Number of Addresses for Block 1
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3
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Number of Registered Messages for Block 1
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2048
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Settings for Blocks 2 - 8
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None
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1104 + [768×{44 + 4 + (3 + 15)÷16×4 + 3×4}] + (4×2048) + (16×2048) + (4×2048)
= 1104 + { 768×(44 + 4 + 4 + 12) } + (4×2048) + (16×2048) + (4×2048)
= 99408 bytes (approximately 97 KB)
1104 + [768×{44 + 4 + (3 + 15)÷16×4 + 3×4}] + { (2048 + 31)÷32 }×4
= 1104 + { 768×(44 + 4 + 4 + 12) } + 64×4
= 50512 bytes (approximately 49 KB)
576 + [768×{28 + 4 + (3 + 15)÷16×4 + 3×4}] + (4×2048) + (16×2048) + (4×2048)
= 576 + { 768×(28 + 4 + 4 + 12) } + (4×2048) + (16×2048) + (4×2048)
= 98880 bytes (approximately 96 KB)
576 + [768×{28 + 4 + (3 + 15)÷16×4 + 3×4}] + { (2048 + 31)÷32 }×4
= 576 + { 768×(28 + 4 + 4 + 12) } + 64×4
= 49984 bytes (approximately 48 KB)