On the other hand, absolute calculations require that the user enter information such as: the
physical dimensions of the PMD and the constant relating to units of measure for both linear
dimensions and flow rates.
Example:
the general formula for flow through a single exponent PMD is:
Q = KH
the specific formula for flow through a 45 ° V-notch weir is:
cfs = 1.03H
thus: Q = flow in cubic feet per second
K = constant of 1.03
H = head in feet
The absolute method is not applicable to the following:
• Palmer Bowlus Flume
• H-Flume
A.7.2
Data Logging
Data logs are available for Alarms, OCM flow, Daily Totals, and Primary Variable. The logs can
be examined locally via LUI (see View Logs (3.2.6.) (Page 247)), or by uploading the logs to a
PC using USB and the Web Browser tool on a computer.
Using the Web Browser tool, choose menu item Maintenance and Diagnostics >
Diagnostics > Data Logs page which displays a Load Logs button. Click this button and you
will be prompted with a dialog box that allows you to choose the location on your local PC
where the uploaded logs will be placed. Note that the logs uploaded at this point will replace
any previous logs you may have uploaded before, so be sure to choose an empty directory
here to avoid losing logs you may have uploaded in the past.
Log files written to a local computer drive via USB, are comma-delimited files, and a list of file
headings for each type of log is shown below.
Log type
Alarms
OCM
SITRANS LUT400
Operating Instructions, 04/2021, A5E33329501-AG
x
2.5
Headings
Date (YYYY/MMM/DD)
Time (HH:MM:SS)
Alarm Name
Value at Transition
Transition Value Units
Alarm State
Date (YYYY/MMM/DD)
Time (HH:MM:SS)
Head
Head Units
Flow
Flow Units
Technical reference
A.7 Flow Calculation
307