Hi,
Is there any option to create a custom measurement in openHistorian such as a new voltage measurement which differs by a constant with respect to another existing voltage measurement?
Thanks,
Dattatreya
FYI, all measurements include an Adder
and Multiplier
for linear adjustments (e.g., y=mx + b
). This adjusts the original measurement. To keep the original measurement value, you can create a clone of the source measurement with its own adjustment, like you suggest. Here are some steps:
The following instructions are executed from the openHistorian Manager (UI app, not web page):
Step 1: Create new output measurement:
- Navigate to
Metadata > Measurements
- Go to last page (
>>
button on bottom right) - Click
(+) Add New
button - Enter a tag name, e.g.,
MY-NEW-VOLTAGE
- Enter a signal reference, e.g.,
MY-NEW-VOLTAGE-PM1
- Enter a description, e.g.,
My new voltage
- Optionally select device from drop-down measurement will be associated with
- Select measurement type, e.g.,
Voltage Magnitude
- Apply an adder or multiplier, like
1.732
(your constant offset) - Check the
Enabled
checkbox - Click
Save
Step 2: Copy input measurement value to new output measurement:
- Navigate to
Actions -> Manage Custom Actions
- Go to last page (
>>
button on bottom right) - Click
(+) Add New
button - Enter a name for the adapter, e.g.,
SET-MY-NEW-VOLTAGE-VALUE
- Select
Dynamic Calculator
from adapter type list - Enter the following adapter parameters:
a)ExpressionText: x
b)FramesPerSecond: 30
c)LagTime: 5
d)LeadTime: 5
e)OutputMeasurements: MY-NEW-VOLTAGE
< Just pick from list
f)VariableList: x = PPA:99
< Set to your input voltage measurement - Check the
Enabled
checkbox - Click
Save
- Click
Initialize
You should now have a value in the MY-NEW-VOLTAGE
measurement that is a copy of your input measurement offset by you applied adder / multiplier.
FYI, see examples for possible complex calculation expressions for the dynamic calculator. Technically you could have applied the adjustment in the expression like so: ExpressionText: x * 1.732
and left the MY-NEW-VOLTAGE
multiplier set at 1.0.
Thanks,
Ritchie