Pild Algorithm; Overview; Block Diagram; Description - ABB 2600T Series Operating Instructions Manual

13 PILD Algorithm

13.1 Overview

The advanced diagnostic transducer block contains all the
parameters that related to the device diagnostic and all the
parameters related with the PILD algorithm. The goal of this
block is to supervise the device and set diagnostic alarms
under transducer abnormal condition to the control system
modifying the pressure transducer block primary value status
and raising the proper alarm bit in the PB_DIAGNOSIS_EXT.

13.2 Block diagram

Figure 46: PILD block diagram

13.3 Description

The Plugged Impulse Line Detection (PILD) is a function aimed
at detecting the blockage of the process connections of the
instrument and any type of problem occurring at the sensor
internal hydraulic circuit. The PILD algorithm is executed in two
distinct phases:

13.3.1 Training phase

Selecting ADTB_PILD_COMMAND = TRAIN the training
phase starts analyses and learns the process dynamics in term
of noises of the primary signal detected when the process is
working at its normal conditions. The Training Phase can take
long time depending by the PILD settings of
ADTB_PILD_TRAIN_TIME, ADTB_PILD_RETRIES, etc.., then
if the training phase is successfully completed with good result,
ADTB_PILD_TRAINING_OUTPUT = PILD_TRAIN_OK the
PILD pass to the second phase of process monitoring
otherwise it is possible read from the
ADTB_PILD_TRAINING_OUTPUT the possible cause like:
— Process Instable during training
— Process not available during training
— Not good process condition for training
— Training not done
46 OI/266/PB-EN Rev. E | 2600T Series Pressure transmitters

13.3.2 Monitoring phase

The algorithms perform a continuous sampling and
comparison of the current process noises with what
memorized during the training phase. Differences have been
experienced being consequences of something bad in
process connections to the sensor like dirty, ice and so on
which tap/plug the pipe/s partially or totally.
Whenever a pipe plugging/tapping is detected, the
ADTB_PILD_OUTPUT that was set to NORMAL during the
monitoring phase changes to one of the following conditions
as well as a correspondent diagnostic bit is raised in the
PB_DIAGNOSIS_EXT:
— Line on side H plugged
— Line on side L plugged
— Both lines H and L plugged
— An undefined line plugged
When one of the above conditions has been detected, there
is the possibility that the process variables in output from the
PRTB continue to be produced with GOOD status. In this way
the AI blocks receiving in input the variables from the PRTB
works normally and the operator could have not evidence of
the wrong conditions. For this reason it is possible make a
choice in order to decide to affect or not the PRTB variables
when the plugging conditions have been detected.
This selection is possible with the ADTB_PILD_AFFECT_PV
variable. When it is selected to true, and the Plugging
conditions are detected, the GOOD status that would be
produced in output for the PRTB_PRIMARY_VALUE,
PRTB_STATIC_PRESSURE_VALUE, PRTB_TEMPERATURE
are forced to BAD status. The PILD algorithm loses the train
every time it is switched off. The algorithm is switched off
automatically for every error condition, except when the
pressure violates the maximum pressure deviation and the
retrain is selected.
13 PILD Algorithm