Emerson Rosemount 3051CF Series Reference Manual page 129

Reference Manual
00809-0100-4774
7.5.6 Trending statistical values in control system
You may view and/or trend SPM Mean and Standard Deviation values in a Fieldbus host
system through the AI function blocks.
You may use an Analog Input (AI) block to read either the Mean or the Standard Deviation
from the SPM Blocks. To use the AI block to trend SPM data, set the CHANNEL parameter
to one of the following values:
Table 7-1: Valid SPM Channels for the AI Block
Channel
12
13
See Table 1
Set the OUT_SCALE parameter to the engineering unit and range which are desired for the
mean and standard deviation output. For example, you can use the OUT_SCALE parameter
to convert mean and standard deviation to some other pressure unit. See
function block
parameters of the AI function block.
7.5.7 SPM configuration with EDDL
SPM configuration provides the capability to configure SPM for use in plugged line
detection, or other abnormal process conditions.
Menu navigation: Configure>Guided Setup>Basic SPM Setup
See Advanced pressure diagnostics
Note
SPM is a factory only option, option code D01, and can't be licensed/installed in the field.
An automated task procedure called a Method guides you through SPM setup. The basic
sequence of steps is:
Procedure
1. Enter the Monitoring Cycle .
2. Bypass Verification, Yes or No.
3. Enter the thresholds in percent.
Reference Manual
SPM variable
SPM mean
SPM standard deviation
for a complete listing of valid Channels for the AI Block.
for additional details on setting the XD_SCALE, OUT_SCALE, and L_TYPE
The minimum monitoring time is one minute; three minutes is a typical monitoring
cycle.
™
Emerson recommends verification for applications where you have not done SPM
monitoring previously or where process changes may cause significant changes in
mean or standard deviation.
a) The first threshold is the Mean Change that will trigger an alert.
b) The second threshold is the High Variation Limit that will trigger an alert.
Typical values are from 40 to 80 percent.
Advanced pressure diagnostics
for more information on SPM functions and uses.
July 2020
Analog input (AI)
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