[CNT_ONTI] Count on-time

Function block CNT_ONTI counts the On-time of a binary signal within a specific time period.

CNT_ONTI counts the On-time of a binary signal within a specific time period.

Functioning

Enable and disable the function

If the function is enabled (EnFnct = 1), then the On-time of the signal at input [In] is recorded.
The On-time is calculated in hours.

Calculation

The present On-time of the signal from the present time period is displayed on [PrVal]. After the time period has expired, the present On-time of the signal is saved as On-time for the recent time period [RctVal] and set to zero via a pulse. The time period, generated outside of CNT_ONTI, is determined via a rising slope on the input [Imp].

Reset

The present and recent On-time is set to zero immediately via a rising slope on input [Reset].

Pins

Input

Description

Data type

Default value
Value range

EnFnct

Enable function

Enables the function.

Boolean

1

0 - The function is disabled.
1 - The function is enabled.

In

Input

Input signal

Boolean

0

0 - Off
1 - On

Imp

Impulse

Pulse input for which the evaluation time period is determined. The rising edge indicates start of new period.

Boolean

0

0 - No
1 - Yes

Reset

Reset

All times are reset to zero.

Boolean

0

0 - No
1 - Yes

Pers

Persistent

Boolean

0

0 - No
1 - Yes: the values are stored persistently.

BaObjRef

BA-Object reference
Link between function block and BACnet object.

Structure

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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

PrVal

Present value

Present value in hours

Real

0.0

RctVal

Recent value

Recent value in hours

Real

0.0

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

= 0 - No error
> 0 - Error codes

Application

CNT_ONTI is used to determine the On-time (runtime) of components or functions. By displaying present and recent On-times from a particular time period, errors can be identified earlier and faster. This can extend the life of monitored components and the time between maintenance intervals as well as reduce energy consumption.

The following example is based on an evaluation period = 1 day: