Micromod MOD: Modcell 2050R Users Guide - Manual (Page 171)

IB-23C650
TUNING
Table 13. Autotune Procedure
Middle
Display
Bottom
Display
Entry Description
INCREASE STEP SIZ The ratio of process oscillation to hysteresis
value is too small for best results. Check tun-
ing constants. If desired, restart autotune with
a larger output step size or a smaller hysteresis
value. Hysteresis must be at least equal to,
and preferably greater than, process noise.
RESPONSE LIMITED The controller is using the high limit for
proportional band or reset. Check tuning
constants. The controller is using the newly
calculated constants. Because of process
characteristics, restart is not likely to improve
tuning constant calculations.
AUTOTUNE FAILED Autotune execution has been canceled, the
controller is in manual, and the output is at the
starting output value. A
PROCESS TOO
SLOW , or a DECREASE STEP SIZ message
follows.
PROCESS TOO SLOW Autotune will not work on this process because
it is too slow.
DECREASE STEP SIZ The process has exceeded one of the
configured process trip-points. Restart
autotune with a smaller output step size or
expand the high and low trip-point of the
process variable.
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