TN Hist226 Scaling an analog tag in the Historian

Description

This article will walk through the process for using the Historian to scale an analog tag.

• Author: Joseph Hefner
• Published: 08/20/2015
• Applies to: Historian 10 and above

Details

The first step is to right click on the tag that you wish to scale and select properties:

Next, confirm the "Current Editor" is Historian and confirm that the Min and Max value are the way that you wish for the data to be displayed after they have been scaled:

Next, Click on the "Acquisition" tab:

Confirm the Scaling is set to "Linear" and the Min and Max Raw values are the Raw Values as they are coming in and click "Apply":

Right Click on the topic and choose "Commit Pending Changes"

Linear scaling for analog tags is performed within retrieval using the following formula.

V_out = (V_in - MinRaw)*(MaxEU - MinEU)/(MaxRaw - MinRaw)
+ MinEU

 where:
V_out = scaled output value
V_in = stored raw value
MinRaw = minimum raw value for the tag
MaxRaw = maximum raw value for the tag
MinEU = minimum engineering unit value
MaxEU = maximum engineering unit value