Discrete Input function block parameters

The following table lists the system parameters for the Discrete Input function block:

Table: Discrete Input 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) or the indication that an error condition (at the module level) not selected in MERROR_MASK is True (Active) or a module status not selected in MSTATUS_MASK is True (Active).
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.
BAD_ACTIVE	None	The indication that a block error condition selected in BAD_MASK (at the function block level) is True (Active) or the indication that an error condition (at the module level) selected in MERROR_MASK is True (Active) or a module status selected in MSTATUS_MASK 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.
BLOCK_ERR	None	The summary of active error conditions associated with the block. The possible block errors for the Discrete Input function block are: Out of Service Input Failure/Bad PV Simulate Active (can be set only when the block is downloaded to a controller)
CHANNEL⁽¹⁾	None	The number of the logical hardware channel that is connected to the I/O block. It defines the transducer to be used going to or from the physical world.
CONDALM_ENABLED⁽¹⁾	None	Enable and disable conditional alarms.
DISC_ACT	None	The result of alarm detection associated with DISC_LIM. If OUT_D equals DISC_LIM, DISC_ACT equals True.
DISC_LIM	None	The state of the discrete input that causes an alarm. Any number from 0 to 255 can be entered, although only 0 and 1 produce an alarm. State 255 specifies that no alarm indication is to be shown.
FIELD_VAL_D	None	The value and status of the discrete input from a field device.
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	None	Defines the input DST for the I/O channel used for the PV.
IO_OPTS	None	The supported I/O option for the Analog Input function block is: Invert
MODE	None	The mode record of the block. Contains the actual, target, permitted, and normal modes.
OUT_D	None	The discrete output value and status.
OUT_STATE⁽¹⁾	None	Index to the text describing the states of a discrete for the value obtained from the transducer.
PV_D	None	The discrete process variable used in block execution.
PV_FTIME	Seconds	The time that FIELD_VAL_D must be on or off before PV_D changes.
SIMULATE_D	None	Enables simulation and allows you to enter an input value and status when SIMULATE_IN_D is not connected.
SIMULATE_IN_D	None	The simulated discrete input value used when simulation is enabled.
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 how status is handled and processed. If the block is assigned to a controller, the available option is: Uncertain if Man mode. If the block is assigned to a fieldbus device, the available options are: Uncertain if Man mode Propagate Fault Forward.
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.
SUBSTITUTE_IN_D⁽¹⁾	None	The substituted (from a field device) discrete input value and status.
XD_STATE⁽¹⁾	None	Index to the text describing the states of a discrete for the value obtained from the transducer.

⁽¹⁾ These parameters are only visible when the function block is extended to a fieldbus device

Note

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

Related information

Status options

I/O options

Inspect with InSight