Parameter data types

Outputs from one function block can be brought into another function block as parameters for calculation or logic functions and sent to other function blocks.

There are a number of data types that SIS function block parameter can have:

Option Bitstring — an unsigned 16-bit integer that contains bit-encoded information that specifies control strategy options, I/O value processing, status handling and processing, or the type of control logic used in the block.
I/O Reference — a value that assigns channel names in an I/O device.
Discrete with Status — an unsigned 8-bit integer value with a status indicator. A value of 0 (zero) means False. A value between 1 and 255 means True.
Simulate Discrete — a discrete value that enables/disables simulation and a simulated discrete value and status.
Floating Point — a number whose decimal point location is not fixed. This allows the calculation to consider significant digits information.
Scaling — a number that is used to convert a floating point value to the required engineering units.
Simulate Floating Point — a discrete value that enables/disables simulation and a simulated floating point value and status.
8-bit Unsigned integer — a whole number without a positive or negative sign associated with it.
Boolean — a True or False value
String — as many as 255 characters
32-bit Unsigned Integer — a whole number without a positive or negative sign associated with it.
Alarm — a value of 0 or 1 (inactive or active) indicating the state of an alarm.

Because data of different types can be transmitted between function blocks, there are rules that govern data compatibility and conversions. The data conversions are performed automatically by the DeltaV software.

The following table lists parameter data type compatibility information:

Table: Function Block Parameter Compatibility
Source Data Type	Destination Data Type	Comments
8-bit Unsigned Integer	8-bit Unsigned Integer	Bit copy full parameter.
	16-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with Status	Current value converted; no data loss.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; no data loss.
	Named Set	Current value converted; no data loss.
16-bit Unsigned Integer	8-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	16-bit Unsigned Integer	Bit copy full parameter.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	Current value converted; clamped to extremes of destination type.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; no data loss.
	Named Set	Current value converted; clamped to extremes of destination type.
32-bit Unsigned Integer	8-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	16-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	32-bit Unsigned Integer	Bit copy full parameter.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; precision loss.
	Floating Point with status	Current value converted; precision loss.
	Discrete with status	Current value converted; clamped to extremes of destination type.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; clamped to extremes of destination type.
	Named Set	Current value converted; clamped to extremes of destination type.
32-bit Unsigned Integer with status	8-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	16-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	32-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	32-bit Unsigned Integer with status	Bit copy full parameter.
	Floating Point	Current value converted; precision loss.
	Floating Point with status	Current value converted; precision loss.
	Discrete with status	Current value converted; clamped to extremes of destination type.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; clamped to extremes of destination type.
	Named Set	Current value converted; clamped to extremes of destination type.
Boolean	8-bit Unsigned Integer	Current value converted; no data loss.
	16-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	Current value converted; no data loss.
	Boolean	Bit copy full parameter.
	Boolean with status	Current value converted; no data loss.
	Option Bitstring	Current value converted; no data loss.
	Named Set	Current value converted; no data loss.
Boolean with status	8-bit Unsigned Integer	Current value converted; no data loss.
	16-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	Current value converted; no data loss.
	Boolean	Current value converted; no data loss.
	Boolean with status	Bit copy full parameter.
	Option Bitstring	Current value converted; no data loss.
	Named Set	Current value converted; no data loss.
Floating Point	8-bit Unsigned Integer	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	16-bit Unsigned Integer	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	32-bit Unsigned Integer	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	32-bit Unsigned Integer with status	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	Floating Point	Bit copy full parameter.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	Current value converted; clamped to extremes of destination type.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; clamped to extremes of destination type.
	Named Set	Current value converted; clamped to extremes of destination type.
Floating Point with status	8-bit Unsigned Integer	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	16-bit Unsigned Integer	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	32-bit Unsigned Integer	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	32-bit Unsigned Integer with status	Current value converted. If the number to be converted is larger than the extremes of the destination type, the previous converted value is retained.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Bit copy full parameter.
	Discrete with status	From 0 to 255, the current value is converted to integer. If the current value becomes greater than 255, the converted value remains at its previous value.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; clamped to extremes of destination type.
	Named Set	Current value converted; clamped to extremes of destination type.
Simulate Float	None	---
Discrete with status	8-bit Unsigned Integer	Current value converted; no data loss.
	16-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	Bit copy full parameter.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; no data loss.
	Named Set	Current value converted; no data loss.
Simulate Discrete	None	---
Option Bitstring	8-bit Unsigned Integer	Current value converted; clamped to extremes of destination type.
	16-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	From 0 to 255, the current value is converted to integer. If the current value becomes greater than 255, the converted value remains at its previous value.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Bit copy full parameter.
	Named Set	Current value converted; clamped to extremes of destination type.
Scaling	Scaling	Bit copy full parameter.
I/O Reference	None	---
Named Set	8-bit Unsigned Integer	Current value converted; no data loss.
	16-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer	Current value converted; no data loss.
	32-bit Unsigned Integer with status	Current value converted; no data loss.
	Boolean	Current value set to zero if source current value equals zero. Else, current value set to one.
	Floating Point	Current value converted; no data loss.
	Floating Point with status	Current value converted; no data loss.
	Discrete with status	Current value converted; no data loss.
	Boolean with status	Current value set to zero if source current value equals zero. Else, current value set to one.
	Option Bitstring	Current value converted; no data loss.
	Named Set	Bit copy plus pointer duplication. Set strings must match.