[HOLD_DI] Hold double integer value

Function block HOLD_DI switches the present or saved input value of data type Double Integer to the output.

HOLD_DI holds the last value on output [Out], if input [Hld] has value 1. If [Hld] has value 0, the present value of input [In] is issued at output [Out].

Pins

Input	Description	Data type	Default value Value range
In	Input	Double integer	0
Hld	Hold	Boolean	0
Hld	0 - Hold is inactive. 1 - Hold is active.
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	Double integer	0
Dstb	Disturbed	Boolean	0
Dstb	0 - Success reading persistent values. 1 - Error reading persistent values.
ErrCode	Error code indication	Integer	0: No error
ErrCode	= 0 - No error > 0 - Error codes

Process response

At start up, HOLD_DI holds the persistent value from the BACnet object. If [Hld] = 1, the read-out persistent value is set and held on output [Out]. If [Pers] = 0 or an access error, output [Out] is set with the input value [In] from the first processed cycle.

The persistent value must be available on the associated BACnet object as an extension property ('Extension by persistence' = 'Hold integer number')

Application example

HOLD_DI is used if input values are acquired and saved for later use. For example, to hold the measured value or the calculated setpoint.