HvacRuntimeCounter (FB)

FUNCTION_BLOCK HvacRuntimeCounter EXTENDS AbbLConC3

HvacRuntimeCounter is a device interface which can be controlled by an input DevOnAuto and an input DevOnManual. DevOnAuto or DevOnManual high turns the device output on. A Reset input is used to reset the runtime counters. When the device was not active for a time RunEvery, the FB turns on the device automatically for MinOnTime. Two setup variables MinOnTime and MinOffTime guarantee a minimum runtime and offtime of the device. If both DevOnAuto and DevOnManual inputs are FALSE, the offtime of the device is determined by RuntimeEvery input.

Let us understand the simple working of the block through the below scenario. Suppose MinOffTime = 7s, MinOnTime = 5s and RunEvery =20s then,

• When DevOnAuto is high, after MinOfftime 7s the DevOn becomes TRUE.

• After DevOnAuto is low, DevOn turns off / becomes low after MinOnTime 5s.

• When DevOnManual is high, the DevOn turns on immediately regardless of MinOfftime and MinOntime.

• When DevOnManual is low, th DevOn turns off immediately regardless of MinOfftime and MinOntime

• If the DevOnAuto or DevOnManual is low for RunEvery time 20s, then the DevOn stays low for 20s, then turns high for MinOnTime 5s, and the cycle continues.

InOut:

Scope	Name	Type	Initial	Comment
Input	DevOnAuto	BOOL	FALSE	1: The device can be turned on automatically with DevOnAuto
	DevOnManual	BOOL	FALSE	2: The device can be turned on manually with DevOnManual
	Reset	BOOL	FALSE	3: Reset input is used to reset the runtime counters
Input Const	MinOnTime	TIME	TIME#10s0ms	1: Set a minimum ON time
	MinOffTime	TIME	TIME#10s0ms	2: Set a minimum OFF time
	RunEvery	TIME	TIME#10000m0s0ms	3: Set a RunEvery time for device to turn on automatically, (Doesnot work with DevOnAuto and DevOnManual inputs being high)
Inout	Runtime	UDINT		1: Counts the device operating hours
	Cycles	UDINT		2: Number of switching cycles
Output	ErrorID	ERROR_ID		1: Error ID of Error
	DevOn	BOOL	FALSE	2: Flag of device on signal