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- All Categories
- Manual
- Match Timestamps for Virtual Variables
Match Timestamps for Virtual Variables
Match Timestamps
When the Virtual Variable Equation includes variables with mismatching timestamps the Non-Matching Timestamps can be selected.
- Main Variable - The selected Main Variable values will be used as a reference when calculating the formula
- Before/After Buffer - Decide how far to search from each timestamp of the Main Variable.
Match Timestamp Calculation Example
The following variables are being used in an equation
Sensor | Sensor Update Rate | Sensor update time (HH:MM) |
A | Hourly | HH:56 |
B | Hourly | HH:31 |
C | 15 Minutes | HH:00, HH:15, HH:30, HH:45 |
Scenario 1.
Equation | Main Variable | Pre Buffer | Post Buffer |
A + C | Sensor C | 30 min | 30 min |
The VV calculates the formula at 15 minute intervals where the C uses its own data and looks for data in A 30 minutes before and 30 minutes after.
Scenario 2.
Equation | Main Variable | Pre Buffer | Post Buffer |
A + B + C | Sensor A | 30 min | 5 min |
The VV calculates the formula hourly with the timestamp as HH:56.
C uses its own data and looks for data in A 30 minutes before and 5 minutes after. This means that at HH:56 if it does not find data for both B and C in the range 30 minutes before and 5 minutes after it will not return anything. And as B only updates at HH:31 this scenario will not return any data.
Note however that it would have found data for C at HH:00 and HH:15. It would use the HH:00 measurement as that is closer.
Scenario 3.
Equation | Main Variable | Pre Buffer | Post Buffer |
A + B + C | Sensor C | 25 min | 20 min |
The VV calculates the formula at 15 minute intervals.
At HH:00 the buffer doesn't reach Sensor B so no reading will be returned there.
At HH:15 the buffer finds values from both A and B and returns normal values
At HH:30 the buffer doesn't reach Sensor A so no reading will be returned there.
At HH:45 the buffer finds values from both A and B and returns normal values
Wait until post buffer is reached
If this option is selected, the calculations will wait until the timestamp of the post buffer is reached to return a value.
Example:
If the current time is 08:53 and the post buffer is set to 10 minutes from the main variable which updates every hour the calculation will not be made until the post buffer timestamp is reached even though the prebuffer finds a valid timestamp.
