Storage and network transmission sizes for tags
- Last UpdatedJan 16, 2025
- 2 minute read
The following table lists the storage and network transmission sizes for various tag types.
|
Tag Type |
Storage Engine - Storage Item Size (Bytes) |
Storage Engine - Network Transmission Item Size (Bytes) |
|---|---|---|
|
Analog - Integer |
8 |
34 |
|
Analog - Floating Point |
8 |
34 |
|
Analog - Double |
12 |
38 |
|
Discrete |
5 |
31 |
|
String |
5+AvgStringLength |
(5+AvgStringLength)+26 |
|
Analog Summary |
37 |
63 |
|
Discrete State Summary |
40 |
66 |
|
Analog State Summary |
28 * NumberOfStates |
(28*NumberOfStates)+26 |
|
String State Summary |
(28+AvgStringLength) * NumberOfStates |
((28+AvgStringLength) * NumberOfStates)+26 |
|
Alarm |
325 |
6,061 |
|
Acknowledgement |
325 |
6,066 |
|
Event |
300 |
5,048 |
The storage size is used for estimating the space required for storage.
The network transmission size is used for calculating the network bandwidth required between the Historian Client Access Level (HCAL) and the Historian.
Note: HCAL is a client-side software layer that provides programmatic access to storage, retrieval, and system configuration functionality in the AVEVA Historian.
If you enable compression on the AppEngine from which events are originating, then the network size is reduced by approximately 80%.
For alarms and events, the network transmission size assumes that the average name length for each of the alarm properties is 20 characters.
The following table provides some sizing examples.
|
Tag Type |
Storage Engine - Storage Item Size (Bytes) |
Storage Engine - Network Transmission Item Size (Bytes) |
|---|---|---|
|
String Tags (32 byte string) |
5+32 = 37 |
(5+32)+26 = 63 |
|
State Summary for Analog (for 10 states) |
28*10 = 280 |
71*10 = 710 |
|
State Summary for Discrete (for 2 states) |
20*2 = 40 |
68*2 = 136 |
|
State Summary for String (10 states and 32 byte string) |
(1+32)*10 = 330 |
(69+32)*10 = 1,010 |
Note: Current space calculations are different from the calculations used by the classic storage system.