PID function block parameters

The following table lists the system parameters for the PID function block:

Table: PID function block system parameters
Parameter	Units	Description
ABNORM_ACTIVE	None	The indication that a block error condition not selected in BAD_MASK (on the function block level) is True (Active).
ALARM_HYS	Percent	The amount the alarm value must return within the alarm limit before the associated active alarm condition clears. ALARM_HYS is limited to 50% of scale.
ALERT_KEY⁽¹⁾	None	A user-assigned identification number reported in alarm messages from the block that allows HMI applications to sort and filter alarms and events. Set this parameter for each function block to indicate the physical unit the function block is associated with. This information can be used in the host for sorting alarms, and so on.
ALPHA⁽²⁾	None	The filter factor for derivative action. The default value is 0.125. The valid range in run time is 0.05 to 1.0. Increasing ALPHA increases damping of derivative action. Adjusting ALPHA can impact the noise protection provided when RATE is utilized. Because of this ALPHA should typically NOT be changed.
ARW_HI_LIM⁽²⁾	OUT	High limit of Anti-Reset Windup. When the output is beyond ARW_HI_LIM and the integral action is returning toward the limit, then the applied RESET time is reduced by a factor of 16. Enter a value between OUT_HI_LIM and OUT_LO_LIM.
ARW_LO_LIM⁽²⁾	OUT	Low limit of Anti-Reset Windup. When the output is beyond ARW_LO_LIM and the integral action is returning toward the limit, then the applied RESET time is reduced by a factor of 16. Enter a value between OUT_HI_LIM and OUT_LO_LIM.
BAD_ACTIVE	None	The indication that a block error condition selected in BAD_MASK (at the function block level) is True (Active).
BAD_MASK	None	The set of active error conditions that triggers a user-defined Bad condition. The user selects a subset of block error (BLOCK_ERR) conditions in the BAD_MASK parameter. When any of these conditions are True, the BAD_ACTIVE parameter becomes True. When any of the BLOCK_ERR conditions that are not included in BAD_MASK are True, ABNORM_ACTIVE becomes True.
BAL_TIME⁽²⁾	Seconds	The time over which an internal balancing bias will be dissipated. Only has practical meaning when the STRUCTURE parameter is a P + D selection.
BETA⁽²⁾	None	Fraction of proportional action applied to SP change. For a value of 0.6, 60% of the proportional action applied to SP change. The value of BETA can be changed over a range of 0-1 if STRUCTURE is set to Two Degrees of Freedom Control. Otherwise, it is automatically set to a value of 1 or 0 based on the Structure selection.
BIAS⁽²⁾	None	The manual reset value applied when STRUCTURE is 'PD action on error' or 'P action on error, D action on PV'. For these structures, the Act on IR control option determines if BIAS is automatically changed to provide bumpless transfer. If not, the factor required for bumpless transfer is ramped out over BAL_TIME.
BKCAL_IN	EU of OUT_SCALE	The analog input value and status from another block's BKCAL_OUT output that is used by an upstream block for bumpless transfer.
BKCAL_OUT	EU of PV_SCALE	The value and status required by the BKCAL_IN input of another block to prevent reset windup and provide bumpless transfer to closed loop control.
BLOCK_ERR	None	The summary of active error conditions associated with the block. The block errors that can appear for the PID function block are: Out of Service Readback Failed Output Failure Input Failure/Bad PV Local Override Simulate Active
BYPASS	None	The Bypass option is intended for slave PID blocks whose PV status is Bad. When BYPASS is on and the block is in AUTO, CAS, or RCAS mode, the block bypasses the normal control algorithm by transferring the SP value (in percent) to OUT. When BYPASS is on and the block is in MAN, ROUT, LO, or IMAN mode, SP is calculated from the value of OUT. The value of SP is not affected by any of the SP-PV track... control options. The value of BKCAL_OUT is not affected by the Use PV for BKCAL_OUT control option. When BYPASS is off, the block operates normally. To turn BYPASS on or off, select the CONTROL_OPTS Bypass Enable option and set the block to MAN or OOS mode, then change BYPASS to On or Off.
CAS_IN	EU of PV_SCALE	The remote analog setpoint value from another block. If the status of CAS_IN is Bad and the target mode is CAS, the actual mode of the PID block sheds to the higher of MAN and the next permitted mode which is usually AUTO.
CONDALM_ENABLED⁽¹⁾	None	Enable and disable conditional alarms.
CONTROL_OPTS	None	Control options allow you to specify control strategy options. When the block is assigned to a controller the valid control options are: No OUT limits in Manual Obey SP lim if Cas or RCas Act on IR Use PV for BKCAL_OUT Track in Manual Track Enable Direct Acting SP Track retained target SP-PV Track in LO or IMan SP-PV Track in ROut SP-PV Track in Man Bypass Enable When the block is assigned to a fieldbus device the valid options are: No OUT limits in Manual Obey SP lim if Cas or RCas Use PV for BKCAL_OUT Track in Manual Track Enable Direct Acting SP Track retained target SP-PV Track in LO or IMan SP-PV Track in ROut SP-PV Track in Man Bypass Enable
DV_HI_ACT	None	The result of alarm detection associated with DV_HI_LIM. If DV_HI_ACT equals True, DV_HI_LIM has been exceeded.
DV_HI_LIM	EU of PV_SCALE	The amount by which PV can deviate above SP before the deviation high alarm is triggered. The magnitude of DV_HI_LIM cannot be greater than the range of PV_SCALE. When this limit is exceeded, DV_HI_ACT is set to True.
DV_LO_ACT	None	The result of alarm detection associated with DV_LO_LIM. If DV_LO_ACT equals True, DV_LO_LIM has been exceeded.
DV_LO_LIM	EU of PV_SCALE	The amount by which PV can deviate below SP before the deviation low alarm is triggered. The magnitude of DV_LO_LIM cannot be greater than the range of PV_SCALE. When this limit is exceeded, DV_LO_ACT is set to True. Note that DV_LO_LIM is a negative number and is compared against PV – SP.
ENABLE_LEARNING	None	Enables or disables Process Learning on the PID block. When Process Learning is enabled (True), the DeltaV system automatically identifies process models and stores a recent history of the models. DeltaV InSight can be used to view, analyze, and select the models that will be used to establish the recommended tuning. This parameter is writeable at runtime. The default value is FALSE. Also, when Process Learning is enabled process learning and adaptive control parameters become available.
ERROR⁽²⁾	EU of PV_SCALE	The difference between SP (setpoint) and PV (process variable).
FF_ENABLE⁽²⁾	None	Enables/disables feedforward control.
FF_GAIN	None	The feedforward gain value. FF_VAL is multiplied by FF_GAIN before it is added to the calculated control output.
FF_SCALE	None	The high and low scale values, engineering units code, and number of digits to the right of the decimal point associated with the feedforward value (FF_VAL).
FF_VAL	EU of FF_SCALE	The feedforward control input value and status.
FIELD_VAL⁽²⁾	Percent	The value and status from the I/O card or from the simulated input if simulation is enabled.
FORM⁽²⁾	None	Selects equation form (series or standard). If Use Nonlinear Gain Modification is selected in FRSIPID_OPTS, the form automatically becomes standard, regardless of the configured selection of FORM.
FRSIPID_OPTS⁽²⁾	None	The supported FRSI add-on control options are: Dynamic Reset Limit Use Delayed OUT on Bad PV Use Nonlinear Gain Modification Use PIDPlus
GAIN	None	The normalized proportional (multiplier) gain value.
GAMMA⁽²⁾	None	Fraction of derivative action taken on SP. For a value of 0.6, 60% of the derivative action is applied to SP. The value of GAMMA can be changed over a range of 0-1 if STRUCTURE is set to Two Degrees of Freedom Control. Otherwise, it is automatically set to a value of 1 or 0 based on the Structure selection.
HI_ACT	None	The result of alarm detection associated with HI_LIM. If HI_ACT equals True, HI_LIM has been exceeded.
HI_HI_ACT	None	The result of alarm detection associated with HI_HI_LIM. If HI_HI_ACT equals True, HI_HI_LIM has been exceeded.
HI_HI_LIM	EU of PV_SCALE	The setting for the alarm limit used to detect the high high alarm condition.
HI_LIM	EU of PV_SCALE	The setting for the alarm limit used to detect the high alarm condition.
IDEADBAND⁽²⁾	EU of PV_SCALE	The dead band value. When the error gets within IDEADBAND, the integral action stops. The proportional and derivative action continue.
IN	EU of PV_SCALE	The analog input value and status (for example, the connection for the PV input from another block).
INSPECT_ACT	None	Indicates if Inspect is enabled and one or more of the limits for the block have been exceeded. The normal value is 0. This parameter is set to 1 only if both of the following conditions are true: The Write to Inspect Alarm context menu item has been selected from Inspect for this block. With the Current Hour filter selected, Inspect indicates that an abnormal condition exists for Mode, Control, Input, or Variability. (Note that an abnormal condition exists for Variability only if both the Variability Index and the Standard Deviation have exceeded their defined limits.)
IO_IN⁽²⁾	None	Defines the input DST for the I/O channel used for the PV.
IO_OPTS⁽²⁾	None	I/O options allow you to select how the I/O signals are processed. When the block is assigned to a controller the supported options are: Low cutoff Increase to close When the block is assigned to a fieldbus device, the IO_OPTS parameter is not available.
IO_OUT⁽²⁾	None	Defines the output DST for the block.
IO_READBACK⁽²⁾	None	Defines the Device Signal Tag (DST) for the input channel that provides readback for the value written to the channel defined by IO_OUT.
L_TYPE⁽²⁾	None	Linearization type. Determines whether the field value is used directly (Direct), is converted linearly (Indirect), or is converted with the square root (Indirect Square Root).
LO_ACT	None	The result of alarm detection associated with LO_LIM. If LO_ACT equals True, LO_LIM has been exceeded.
LO_LIM	EU of PV_SCALE	The setting for the alarm limit used to detect the low alarm condition.
LO_LO_ACT	None	The result of alarm detection associated with LO_LO_LIM. If LO_LO_ACT equals True, LO_LO_LIM has been exceeded.
LO_LO_LIM	EU of PV_SCALE	The setting for the alarm limit used to detect the low low alarm condition.
LOW_CUT⁽²⁾	EU of PV_SCALE	Activated when the Low Cutoff I/O option is enabled. When the converted measurement is below the LOW_CUT value, the PV is set to 0.0.
MODE	None	Parameter used to show and set the block operating state. MODE contains the actual, target, permitted, and normal modes.
NL_GAIN_MOD		The multiplier applied to GAIN when the Use Nonlinear Gain Modification option is selected in FRSIPID_OPTS.
NL_GAP⁽²⁾	EU of PV Scale	The configured range of ERROR, positive or negative, where the gain modifier is at a minimum value. The range is 0->(PV_SCALEHI-PV_SCALELO).
NL_HYST⁽²⁾	EU of PV Scale	Gap action hysteresis value. The range is 0->(PV_SCALEHI-PV_SCALELO).
NL_MINMOD⁽²⁾	None	The configured minimum gain modifier. The range is 0->1.0.
NL_TBAND⁽²⁾	EU of PV Scale	The configured range of ERROR, positive or negative, where the gain modifier transitions between NL_MINMOD and 1.0. The range is 0->(PV_SCALEHI-PV_SCALELO).
OUT	EU of OUT_SCALE	The analog output value and status.
OUT_HI_LIM	EU of OUT_SCALE	The maximum output value allowed.
OUT_LO_LIM	EU of OUT_SCALE	The minimum output value allowed.
OUT_READBACK⁽²⁾	EU of OUT_SCALE	The value and status of the output channel referenced by IO_READBACK.
OUT_SCALE	None	The high and low scale values, engineering units code, and number of digits to the right of the decimal point associated with OUT.
PLUGINSTAT_OPTS	None	Reports the status of the ENABLE_LEARNING parameter. If the value for: ENABLE_LEARNING is True and PLUGINSTAT_OPTS is 1, Process Learning is enabled for the PID block. ENABLE_LEARNING is False and PLUGINSTAT_OPTS is 0, Process Learning is disabled for the PID block. ENABLE_LEARNING is True and PLUGINSTAT_OPTS is 0, Process Learning is not enabled for the PID block.
PROCESS_TYPE	None	Defines the expected type of process response: Self Regulating or Integrating
PV	EU of PV_SCALE	The process variable used in block execution and alarm limit detection. Note A PID block will not integrate if the limit status of PV is CONSTANT.
PV_FTIME	Seconds	The time constant of the first-order PV filter.
PV_SCALE	None	The high and low scale values, engineering units code, and number of digits to the right of the decimal point associated with PV.
RATE	Seconds	The derivative action time constant.
RCAS_IN	EU of SP_SCALE	The remote analog setpoint value and status. Input provided by a device or the output of another block.
RCAS_OUT	EU of PV_SCALE	The output provided for bumpless mode transfer and reset limiting by the source of RCAS_IN. Essentially the equivalent of BKCAL_OUT for RCAS_IN.
RECOVERY_FLTR	None	Saturation recovery filter. Ignored unless FRSPID_OPTS PIDPlus is selected. Valid values between 0.0 and 1.0. A value of 1.0 behaves like previous releases. The smaller the value the more aggressive the response.
RESET	Seconds per repeat	The integral action time constant.
ROUT_IN	EU of OUT_SCALE	Remote output value and status. Input provided by a device to the control block for use as the output (ROut mode)
ROUT_OUT	EU of OUT_SCALE	The output provided for bumpless mode transfer and reset limiting by the source of ROUT_IN. Essentially the equivalent of BKCAL_OUT for ROUT_IN.
SHED_OPT	None	Defines action to be taken on remote control device timeout.
SHED_TIME⁽²⁾	Seconds	The maximum allowable time between RCAS_IN or ROUT_IN updated. If exceeded, mode shedding takes place.
SIMULATE⁽²⁾	Percent	Enables simulation and allows you to enter an input value and status. The SIMULATE value is used by the block only when SIMULATE_IN is not connected or updated by an application (as indicated by a SIMULATE_IN status of Bad Not Connected).
SIMULATE_IN⁽²⁾	Percent	The input connector value and status used by the block instead of the analog measurement when simulation is enabled. If SIMULATE_IN is connected or has a manually entered value, SIMULATE_IN always overrides SIMULATE. Note When SIMULATE_IN is wired from an input source on the function block diagram, it always overrides a manually entered value in SIMULATE.
SP	EU of PV_SCALE	The block's setpoint value.
SP_FTIME	Seconds	Time constant of the first order SP filter.
SP_HI_LIM	EU of PV_SCALE	The highest SP value allowed.
SP_LO_LIM	EU of PV_SCALE	The lowest SP value allowed.
SP_RATE_DN	EU of PV_SCALE per second	Ramp rate at which downward setpoint changes are acted on in Auto mode, in PV units per second. If the ramp rate is set to 0.0, then the setpoint is used immediately. For control blocks, rate limiting applies only in Auto. For output blocks, rate limiting applies in Auto, Cas, and RCas modes.
SP_RATE_UP	EU of PV_SCALE per second	Ramp rate at which upward setpoint changes are acted on in Auto mode, in PV units per second. If the ramp rate is set to 0.0, then the setpoint is used immediately. For control blocks, rate limiting applies only in Auto. For output blocks, rate limiting applies in Auto, Cas, and RCas modes.
SP_WRK	EU of PV_SCALE	The working setpoint of the block subjected to SP_RATE_DN and SP_RATE_UP.
ST_REV⁽¹⁾	None	The revision level of the static data associated with the function block. To support tracking changes in static parameter fields, the associated block's static revision parameter is incremented each time a static parameter field value is changed. Also, the associated block's static revision parameter is incremented if a static parameter field is written but the value is not changed.
STATUS_OPTS	None	Status options determine status handling and processing. If the block is assigned to a controller, the available options are: Bad if Limited Uncertain if Limited Target to Manual if Bad IN Use Uncertain as Good If the block is assigned to a fieldbus device, the available options are: Target to Manual if Bad IN Use Uncertain as Good IFS if Bad CAS_IN IFS if Bad IN
STDEV	EU of OUT_SCALE or EU of PV_SCALE (reports in percent to Inspect)	The standard deviation of PV. For analog control blocks in AUTO, mean is assumed to be the SP.
STDEV_CAP	EU of OUT_SCALE or EU of PV_SCALE (reports in percent to Inspect)	The estimated capability standard deviation (measurement of short term variation). An estimate of the least standard deviation the process could achieve ideally.
STDEV_TIME	Seconds	The time frame over which STDEV and STDEV_CAP are performed. The default value of zero is good for most processes where the scan rate is no more than approximately 10 times faster than the time to steady state. If the process is relatively much slower, it is recommended that you enter the approximate time it takes for the process to return to steady state after a change. This ensures that the STDEV and STDEV_CAP calculations accurately consider the actual time constant of the process.
STRATEGY⁽¹⁾	None	Used to identify groupings of blocks. This data is not checked or processed by the block.
STRUCTURE⁽²⁾	None	Defines PID equation structure to apply controller action.
TRACK_OPT⁽²⁾	None	Tracking Option. Allows you to select the tracking behavior when the status of the TRK_IN_D is Bad. The three tracking options are Always Use Value - The block reacts to the current value of TRK_IN_D regardless of the status. Use Last Good Value - The block uses the value of TRK_IN_D the last time its status was not Bad. This is the default value for TRACK_OPT. Note that the last good value is not preserved on controller switchover. Track if Bad - If the status of TRK_IN_D is Bad, the block reacts as if the value if True, even if the value is False.
TRK_IN_D	None	Discrete input that initiates external tracking.
TRK_SCALE	None	The high and low scale values, engineering units code, and number of digits to the right of the decimal point associated with the external tracking value (TRK_VAL).
TRK_VAL	EU of TRK_SCALE	The analog input used in the external tracking function.
VAR_IDX	None	The Variability Index that is calculated based on the values of STDEV and STDEV_CAP. The range is 0-100.
VAR_IDX_LIM	None	For Control blocks only, Inspect marks the blocks as having Large Variability if the value of STDEV exceeds the value of STDEV_LIMIT. The range is 0-100.

⁽¹⁾ These parameters are only visible in one or more of the extended versions of this block

⁽²⁾ These parameters may not be visible in certain extended versions of the block.

Note

Default values and data type information for the parameters are available by expanding the Parameter View window.

Related information

PID function block process learning and adaptive control parameters

Inspect with InSight