I/O Blocks > Smart HART Discrete Output (SHDO) function block

Smart HART Discrete Output function block parameters

The following table lists the system parameters for the Smart HART Discrete Output (SHDO) function block:

Table: SHDO function block 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).

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 Manual Loader function block are:
  • Out of Service.

CAS_IN_STATE (1)

None

The input that can be a Named Set value from same named set as SP. If the block is in Cascade (CAS) mode, a signal from another block wired to CAS_IN_STATE changes the setpoint

DEVICE_OPTS

None

The supported control options are:
  • SP Track on Tracking

DEVICE_STATE

None

Displays the named state string associated with the value that is either sent to device (if readback is configured) or the value that is read back from the DST that is assigned to IO_READBACK. The default named set is $discrete_hart_states.

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_OUT

None

Defines the output DST for the block.

IO_READBACK

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.

MODE

None

Parameter used to request and show the source of the output used by the block. Supported modes are:
  • Out of Service (OOS) - The block algorithm is not active. The output is maintained at the last value or at a specified failure action value.
  • Cascade (Cas) - This mode is similar to Auto except that the setpoint is supplied by another function block through the CAS_IN_STATE parameter
  • Automatic (Auto) - Set the setpoint locally

OUT_STATE

None

The named set state value and status going to a discrete output variable.

SIMULATE_D

None

Enables simulation and allows you to enter an input value and status for DEVICE_STATE.

SP(1)

None

The set point from a named set that is configurable but cannot be changed online.

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_LIMIT

Percent

Used to calculate a process parameter's standard deviation percent of time out of standard deviation limit

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.

TRACK_OPT

None

Options on how tracking will behave based on the status of TRK_IN_D. Supported options are:
  • Always use value
  • Use last Good value
  • Track if Bad

TRK_IN_D

None

Discrete input that initiates output tracking (True (1) = active, False (0) = inactive). TRK_IN_D is acted on only when the Track Enable and/or Track in Manual control options are selected.

TRK_STATE(1)

None

The Named Set input used in the external tracking function.

(1) The acceptable values are based on the configured Named Set .