Loop control setup
The Loop Control Setup Display shows parameters of the selected loop. The table below lists all
parameters for all loop types. Items marked with * are visible depending on loop type.
SP High Lim*
SP Low Lim*
SP Rate Up Lim*
SP Rate Down Lim*
PV High Lim
PV Low Lim
Out High Lim*
Out Low Lim*
Autotune Out High Lim*
Autotune Out Low Lim*
Ratio Gain *
Ratio Bias *
Motor Deadband % *
Motor Traverse Time (Sec) *
Value of Local Setpoint.
Value of Remote Setpoint. This value is changeable only if it is configured as a
second Local Setpoint (LSP2). It is read-only if it is connected to a function
block within the configuration.
Loop's output during a failure.
Highest allowable setpoint value.
Lowest allowable setpoint value.
Highest allowable rate at which a setpoint changes to a higher value.
Highest allowable rate at which a setpoint changes to a lower value.
Highest allowable PV value.
Lowest allowable PV value.
Highest allowable loop output value.
Lowest allowable loop output value.
Highest value of the output beyond which the motor no longer affects the
Lowest value of the output beyond which the motor no longer affects the
Gain value for a ratio loop.
Local bias value in engineering units. Enterable only if it is configured for local
bias. It is read-only if it is configured for remote bias.
Value of adjustable deadband in %.
Motor travel time in seconds.
Loop alarm's hysteresis. 0 to 10% of PV range.
Lets you adjust the % Carbon as measured by the controller to agree with the
results of actual shim stock tests. This adjustment may be needed to correct
for specific furnace characteristics such as atmosphere differences, probe
location, and furnace leaks.
Lets you adjust the anti-sooting factor, which limits the %C working setpoint of
the downstream control block to a value which will not permit sooting to occur
in the furnace. When anti-sooting is ON, then the anti-sooting factor is
calculated as a linear translation of probe temperature to %C clamped at
0.75% and 2.0%. When anti-sooting is OFF, then the factor is fixed at 2.0% for
Lets you adjust % hydrogen, one of the factors in the dewpoint calculation. The
dewpoint calculation is a function of the mV input (IN) from the oxygen probe,
temperature of the probe, and %H. The equations used are probe-type
dependent and are supplied by the manufacturer.
900 Control Station User Guide