ALN, ALNI – Alarms for numerical value

Block SymbolsLicensing group: STANDARD

Function Description
The ALN and ALNI blocks generate two-level alarms or events when a limit value is exceeded (or not reached). There are four limit values the input signal u is compared to, namely high-limits h and hh and low-limits l and ll. The iac output shows the current alarm (event) code.

The ALNI block is an extension of the ALN block as the alarms (events) are indicated also by Boolean output signals HHA, HA, LA and LLA and the variables of the alarm algorithm are given by the input signals hys, hh, h, l and ll instead of parameters with the same name and meaning.

The events and alarms are differentiated by the lvl parameter in the REXYGEN system. The range $1 \leq lvl \leq 127$ is reserved for alarms. All starts, ends and acknowledgements of the alarms are stored in the archive. On the contrary, the range $128 \leq lvl \leq 255$ indicates events. Only the start (the time instant) of the event is stored in the archive.

Inputs

u	Analog input of the block which is checked to remain within the given limits	Double (F64)
hys	Alarm hysteresis for switching the alarm off $↓$ 1e-10 $↑$ 1e+10	Double (F64)
hh	The second high-alarm limit, must be greater than h	Double (F64)
h	High-alarm limit, must be greater than l	Double (F64)
l	Low-alarm limit, must be greater than ll	Double (F64)
ll	The second low-alarm limit	Double (F64)
iACK	Alarm is acknowledged on rising edge of the individual bits of this input/parameter. E.g. value 15 acknowledges all alarms.
	Byte (U8)
	1 .... Second low-alarm acknowledge 2 .... Low-alarm acknowledge 4 .... High-alarm acknowledge 8 .... Second high-alarm acknowledge

In case a one-level alarm is required, it is sufficient to set lvl2=0 or set the hh and ll limits to extreme values which can never be reached by the input signal.

Outputs

iac	Current alarm code. Additional bitwise combinations of the codes may appear. E.g. 12 means both high alarms.	Long (I32)
	0 .... Signal within limits 1 .... Low-alarm active 2 .... High-alarm active 4 .... Second low-alarm active 8 .... Second high-alarm active 256 .. Low-alarm not acknowledged 512 .. High-alarm not acknowledged 1024 . Second low-alarm not acknowledged 2048 . Second high-alarm not acknowledged -1 ... Invalid alarm limits
E	Error flag	Bool
	off .. No error on ... An error occurred, alarm limits disordered
HHA	The second high-alarm indicator	Bool
HA	High-alarm indicator	Bool
LA	Low-alarm indicator	Bool
LLA	The second low-alarm indicator	Bool
NACK	Alarm-not-acknowledged indicator	Bool

Parameters

acls	Alarm class (data type to store) $⊙$ 8	Byte (U8)
	1 .... Bool 2 .... Byte (U8) 3 .... Short (I16) 4 .... Long (I32) 5 .... Word (U16) 6 .... DWord (U32) 7 .... Float (F32) 8 .... Double (F64) –- ... 10 ... Large (I64)
arc	List of archives to store the events. The format of the list is e.g. 1,3..5,8. The event will be stored in all listed archives (see the ARC block for details on archives numbering). Third-party programs (Simulink, OPC clients etc.) work with an integer number, which is a binary mask, i.e. 157 (binary 10011101) in the mentioned case.	Word (U16)
id	Identification code of the alarm in the archive. This identifier must be unique in the whole target device with the REXYGEN control system (i.e. in all archiving blocks). Disabled for $id = 0$ . $⊙$ 1	Word (U16)
lvl1	The level of first high- and low-alarms (HA and LA) which differentiates alarms from events and defines the severity of the alarm/event $↓$ 1 $⊙$ 1	Byte (U8)
lvl2	The level of second high- and low-alarms (HHA and LLA) which differentiates alarms from events and defines the severity of the alarm/event $↓$ 1 $⊙$ 10	Byte (U8)
Desc	Extended description of the alarm which is displayed by the diagnostic tools of the REXYGEN system $⊙$ Alarm Description	String

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