Revision 2.0 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide Page 103
Troubleshooting the Proportional Integral Derivative (PID) block
Table 25: PID block
Problem Cause Things to check Recommended action
PID block mode is in
OOS mode, and does not
change to AUTO, CAS,
RCAS and ROUT mode.
Read
MODE_BLOCK.PERMITTED.
Add AUTO, CAS, RCAS and ROUT
modes to
MODE_BLOCK.PERMITTED.
Read MODE_BLOCK. ACTUAL of
Resource block.
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.
Schedule Block is not scheduled and therefore
cannot execute to go to Target Mode.
Schedule the block to execute.
PID block mode is in
OOS mode with Block
configuration Error.
Read parameters:
BYPASS
SHED_OP
The default values of these
parameters are configuration errors
and they must be set to a valid range.
See Table 30.
Read
SP_HI_LIM, SP_LO_LIM
OUT_HI_LIM, OUT_LO_LIM
Check that SP_HI_LIM <
SP_LO_LIM, OUT_HI_LIM <
OUT_LO_LIM.
PID block is not running. Read the first element of
BLOCK_TEST. Number must be
increasing indicating that block is
running.
If the second element of
BLOCK_TEST is nonzero, write all
zeroes to element.
Mode does not change
from IM, target mode is
MAN, AUTO, or Cas.
No path to process. 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.
Mode does not change
from MAN; target mode is
MAN, AUTO, or Cas.
Check Input blocks. The status of IN is Bad, not
connected.
Mode does not go to Cas,
target mode is Cas.
Check Upstream block. 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.
Value of output does not
make sense
Check Cascade Initialization Assure that the output can move an
actuator.
Block alarms are not
reported
Read FEATURE_SEL Reports are not selected in
FEATURE_SEL. If features do not
include Reports then the host must
poll for alarms.
Read LIM_NOTIFY Set LIM_NOTIFY to a value higher
than zero, but not higher than
MAX_NOTIFY.
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