Siemens Moore 353 User Manual page 244

Operation
Chart 2
Autotuner Errors - terminate the autotune exercise and returns the control loop to the point prior to the start of
autotune. An Error message can be cleared by pressing the ACK button.
ERROR DESCRIPTION
E1 A zero crossing did not occur within 120 minutes. Most likely caused by the control loop not being
in a steady state condition when the autotuner was started.
E2 Process went out of range twice (<0%, >100%). The first time an out of range occurs, the autotuner
will cut the valve step size in half and restart the exercise.
E3 When the autotune algorithm has been set to HYS = A and it calculates a required hysteresis value
greater than 10%. Process filtering should be added to reduce the noise seen by the autotuner.
Autotuner Warnings - do not terminate the autotune exercise and are normally eliminated by increasing the %
HYS and/or the % DEV settings. In some cases, they may have been caused by load changes that occurred during
the autotune exercise. The autotuner will still derive recommended tuning values but they will not automatically be
transferred to the controller, if that feature was requested. The warnings can be cleared by pressing the ACK
button.
WARNING DESCRIPTION
W1 Indicates that the % DEV setting is not greater than 4 times the % HYS setting.
W2 Indicates that the process deviations during the first one and a half cycles, where the autotuner first
learns about the process gain, were inconsistent.
W3 Indicates that the average % DEV values during the final phase of the autotuning exercise were not
greater than 4 times the % HYS setting. If this warning occurs while the % DEV selection was set to
A (auto selection of deviation setting), the use of manual entry should be considered.
9-6
TABLE 9.1 Autotune Errors
TABLE 9.2 Autotune Warnings
UM353-1
March 2003