Troubleshooting The Proportional Integral Derivative (Pid) Block; Table 25: Pid Block - Honeywell ST700 User Manual

Troubleshooting the Proportional Integral Derivative (PID) block

Problem Cause
PID block mode is in
OOS mode, and does not
change to AUTO, CAS,
RCAS and ROUT mode.
PID block mode is in
OOS mode with Block
configuration Error.
PID block is not running.
Mode does not change
from IM, target mode is
MAN, AUTO, or Cas.
Mode does not change
from MAN; target mode is
MAN, AUTO, or Cas.
Mode does not go to Cas,
target mode is Cas.
Value of output does not
make sense
Block alarms are not
reported
Revision 2.0 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide

Table 25: PID block

Things to check
Read
MODE_BLOCK.PERMITTED.
Read MODE_BLOCK. ACTUAL of
Resource block.
Schedule
Read parameters:
BYPASS
SHED_OP
Read
SP_HI_LIM, SP_LO_LIM
OUT_HI_LIM, OUT_LO_LIM
Read the first element of
BLOCK_TEST. Number must be
increasing indicating that block is
running.
No path to process.
Check Input blocks.
Check Upstream block.
Check Cascade Initialization
Read FEATURE_SEL
Read LIM_NOTIFY
Recommended action
Add AUTO, CAS, RCAS and ROUT
modes to
MODE_BLOCK.PERMITTED.
If necessary, Set
MODE_BLOCK.TARGET to AUTO.
NOTE: If the mode is set to OOS for
maintenance then do not change the
mode to AUTO.
Block is not scheduled and therefore
cannot execute to go to Target Mode.
Schedule the block to execute.
The default values of these
parameters are configuration errors
and they must be set to a valid range.
See Table 30.
Check that SP_HI_LIM <
SP_LO_LIM, OUT_HI_LIM <
OUT_LO_LIM.
If the second element of
BLOCK_TEST is nonzero, write all
zeroes to element.
Assure that the downstream blocks to
at least one AO are all in Cas mode
and that the path ends in an AO
block. All BKCAL connections must
be linked.
The status of IN is Bad, not
connected.
The upstream block cannot not able
to complete cascade initialization for
some reason. Assure that
BKCAL_OUT is connected to
BKCAL_IN of the upstream block.
Assure that the output can move an
actuator.
Reports are not selected in
FEATURE_SEL. If features do not
include Reports then the host must
poll for alarms.
Set LIM_NOTIFY to a value higher
than zero, but not higher than
MAX_NOTIFY.
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