Loops
Loop Setup
150 900 Control Station User Guide Revision 9
May 2014
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.
Item Description
Local Setpoint* Value of Local Setpoint.
Remote 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.
Failsafe Output Loop’s output during a failure.
SP High Lim* Highest allowable setpoint value.
SP Low Lim* Lowest allowable setpoint value.
SP Rate Up Lim* Highest allowable rate at which a setpoint changes to a higher value.
SP Rate Down Lim* Highest allowable rate at which a setpoint changes to a lower value.
PV High Lim Highest allowable PV value.
PV Low Lim Lowest allowable PV value.
Out High Lim* Highest allowable loop output value.
Out Low Lim* Lowest allowable loop output value.
Autotune Out High Lim* Highest value of the output beyond which the motor no longer affects the
process.
Autotune Out Low Lim* Lowest value of the output beyond which the motor no longer affects the
process.
Ratio Gain * Gain value for a ratio loop.
Ratio Bias * 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.
Motor Deadband % * Value of adjustable deadband in %.
Motor Traverse Time (Sec) * Motor travel time in seconds.
Hysteresis* Loop alarm’s hysteresis. 0 to 10% of PV range.
Furnace Factor* 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.
Anti-Sooting* 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
all temperatures.
% Hydrogen* 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.
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