[INTEGRAL] Integral function

Function block INTEGRAL calculates the area of the integrated input value over time.

INTEGRAL calculates the area for an integrated input value over time.

The units of the integrated sums can be modified using a conversion factor.

INTEGRAL cyclically acquires the input value [In] and integrates it by time. The present result is provided at output [Out].

Input enable function [EnFnct] can be used to start the integration. For [EnFnct] = 0, the value on output [Out] is set to 0.0 and the present integrated sum is retained internally.

Set start value

The output value [Out] for the integrated sum can be set to a predefined start value on input [SttVal], prior to or during the integration process. The start value must be less than the counter limit. The output value is set to the start value, if the value on input set start value [SetStt] is set to 1.

Set counter limit

The counter value limit [CntValLm] is the high limit for the integrated sum, at which the integration is restarted and [LmRd] is set to 1 for one cycle.

Set conversion factor

INTEGRAL uses the unit seconds for time in internal calculations. The conversion factor can be set if a value on input [In] is in minutes or hours.

Input value [Unit]	Conversion	Conversion factor	Modified input value [Unit]
		0.000278
		0.016667

Enable negative value count

If the input [EnCntDn] is set to 1, the function block considers the negative input values. As a result, sums with negative values can be generated at the output.

If only positive input values are expected, [EnCntDn] can be set to 0 to avoid processing measurement errors.

Pins

Input	Description	Data type	Default value Value range
EnFnct	Enable function Enables the function.	Boolean	1
EnFnct	0 - The function is disabled. 1 - The function is enabled.
In	Input	Real	0.0
SetStt	Set start value	Boolean	0
SetStt	0 - Do not set start value. 1 - Set start value.
SttVal	Start value Start value for the integrated sum.	Real	0.0
CntValLm	Counter value limit The limit for the integrated sum.	Real	0.0
CnvFac	Conversion factor Conversion factor to modify the unit for the output value.	Real	1.0
EnCntDn	Enable count for negative values	Boolean	1
EnCntDn	0 - Ignore negative values. 1 - Consider negative values.
TshVal	Threshold value Configured value to control function block write attempts. An attempt is permissible only if the change of value is greater than or equal to [TshVal]. Note Cannot be set to 0.0.	Real	0.1
Pers	Persistent	Boolean	0
Pers	0 - No 1 - Yes: the values are stored persistently.
BaObjRef	BA-Object reference Link between function block and BACnet object.	Structure	---
BaObjRef > DeviceID	Device identifier [DeviceID] includes object type and object instance in one ID. Identifies the device object: local or remote. A local device object can also be identified by value 16#3FFFFF.	Double Word	16#3FFFFF
BaObjRef > ObjectID	Object identifier [ObjectID] includes object type and object instance in one ID. Identifies the object on a device.	Double Word	16#3FFFFF
BaObjRef > ItemID	Item identifier [ItemID] represents an index in a view node object that references the BACnet object. [ObjectID] and [ItemID] together define an indirect reference to the BACnet object. Value -1 indicates a direct interface.	Integer	-1

Output	Description	Data type	Default value Value range
Out	Output	Real	0.0
LmRd	Limit reached Triggers an impulse if [Out] is greater than or equal to [CntValLm].	Boolean	0
Dstb	Disturbed [Dstb] indicates whether the referenced BACnet object was accessed. [Dstb] = 0, if: BACnet object access = Access successful [Dstb] = 1, if: BACnet object access = Error during access	Boolean	0
ErrCode	Error code indication	Integer	0: No error
ErrCode	= 0 - No error > 0 - Error codes

Application example

INTEGRAL is used wherever input values are summed up over time:

Calculate volume [m3] from volume flow [m3/s]
Calculate electrical energy [kWh] from electrical power [kW]

Process response

The function blocks reads the last saved integral value from the BACnet object at start up and uses the value as the first integral sum if [Pers] = 1. The integral sum begins at 0 in the event of an error, or if [Pers] = 0.

The properties 'top row value' and 'old start value' are must be available on the associated BACnet object as extension property ('Extension by persistence' = 'Integral').