Event variable
Defines the name of the variable that triggers the alarm/alarms.
Depending on the alarm type, the event variable has the following function:
|
Type |
Description of the |
|---|---|
|
Bit |
The alarm is triggered when the bit specified via bit number in the event variable assumes the value 1. The 0-active parameter has an inverting function here. If 0-active is set, the alarm is triggered when the event bit assumes the value 0. |
|
Bit block |
The event variable specified in the alarm applies to all assignments specified in the bit block type. Each assignment contains the bit number parameter. |
|
Numerical |
A numerical process variable is specified here as an event variable. The assignments in the numerical alarm type each contain a value that is compared with the current value of the event variable. |
A bit range can be specified in the selection dialogue for the event variable. This specification is used to mask out a range of bits from the event variable.
Bits 4-7 are masked out of the event variable by specifying the bit range.
At runtime, the event variable assumes the value 52 (binary 00110100).
The masked bits have the value 0011, i.e. 3. This value is now used as the value of the event variable, i.e. both the specification of the bit numbers and the value specification in the numerical alarm type refer to the value masked in this way.
Parameters for module: