Moog ACV with CANopen bus interface
7 Servo valve functions
Event handler
B99224-DV018-D-211, Rev. A, October 2018
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7.16 Event handler
With the event handler, the user can define expressions to calculate a value depending on internal and exter-
nal parameter values and assign it to any parameter.
All actions are based on parameter access, so the behavior of the servo valve can be influenced similar to an
external parameter access via the field bus. The variables calculated by the event handler can be accessed
via the field bus. There are in total eight event handlers, which will be configured by eight associated strings
processed by the expression parser.
After an event handler is configured, it needs to be enabled in order to process its low-level code. The parser
processes the expressions according the syntax and the processing order similar to that of the programming
language C. All event calculations are processed every main task cycle of the firmware, which is processed at
least every 2 ms.
7.16.1 Event expressions
The event expressions are strings with maximal 192 characters and are built in the following manner:
• The parameters to be used can only be accessed through their short names. The short names of a pa-
rameter can be found in the chapter "Object dictionary"
Chapter "10 Object dictionary", page 298
• Integer constants
• Floating point constants are not allowed.
There are groups of operators. Inside a group there is no priority of operation, the expressions are processed
from left to right. The groups are listed in order of their priority.
• Operators with one operant
• Mathematical operators high priority
• Mathematical operators low priority
Prefix
Description
Decimal integer constants
0x
Hexadecimal integer constants
Symbol
Description
–
Negate / negative sign
+
Positive sign
#
Absolute
~
Bitwise NOT
!
Logical NOT
Symbol
Description
/
Divide
*
Multiply
Symbol
Description
–
Subtract
+
Add
