Tuning Parameters

You can use the following tuning parameters to adjust the control settings of the FP-3000.

BAL_TIME
Time, in seconds, for the bias or ratio to change from the internal working value to the operator set value. Also, the time constant used by the integral term of the PID to obtain balance when the output is limited and the block is in Auto, Cas, or RCas mode.

BIAS
The bias value, in engineering units, used to calculate the function block output.

BYPASS
Allows the normal control algorithm to be bypassed if the CONTROL_OPT parameter’s Bypass Enable option is selected. If control is bypassed, the PID uses its setpoint value in percent of scale as its output value and does not attempt to do any PID control.

CYCLE_SEL
Identifies the block execution methods available. Unused in National Instruments FP-3000.

CYCLE_TYPE
Used to select the block execution method. Unused in National Instruments FP-3000.

FF_GAIN
The gain by which the feed-forward input is multiplied before it is added to the output value of the control block.

FF_VAL
The feed-forward value.

FIELD_VAL
The value from the input channel, in percent of scale.

FIELD_VAL_D
The value from the discrete input channel.

GAIN
The gain constant used by the PID in calculating the proportional component of the output.

IN
The primary input of the block.

IN_1
The secondary input of the block.

LOW_CUT
With an L_TYPE of Indirect Square Root, this can be used to establish a floor (in percent of scale) for values from the transducer. Values below this floor are considered to be zero. This feature must first be enabled by setting Low Cutoff in the IO_OPTS parameter.

OUT
The current output value of the block.

PV
The process variable being controlled by the process.

PV_FTIME
The filter time constant, in seconds, used in input blocks for the process variable. For analog blocks, it is the time constant for a low pass exponential filter used to damp out rapid oscillations in the input value before using it as the process variable. For discrete blocks, it is the time the PV must remain constant after a change for the change to be reported.

RA_FTIME
The filter time constant, in seconds, for the value to be used in the ratio.

RATE
The derivative time constant, in seconds.

READBACK
The valve or actuator position read back from the transducer, in transducer units.

RESET
The time constant for the integral component of the PID block. It is measured in seconds per repeat.

SEL_1 through SEL_3
Input values for the selector.

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