csmstr - Omega Engineering

SIMPLE MATH
CRIMSON USER MANUAL - MODULAR CONTROLLER
has been entered, any changes to the name of the tag will modify all of the expressions that
make reference to it, so there is no need to re-edit the expressions to “fix” the name.
COMMUNICATIONS REFERENCES
References to registers in master communications devices can be entered into an expression
by means of a syntax comprising an opening square bracket, the register name, and a closing
square bracket. An optional device name may be prefixed to the register name and separated
by a period. The device name need not be specified for registers in the first (or only) device
within the database. Examples of this syntax are shown below…
EXAMPLE
[D100]
[AB.N7:0]
[FX.D100]
MEANING
Register D100 in first device.
Register N7:0 in device AB.
Register D100 in device FX.
SIMPLE MATH
As mentioned above, expressions often contain more than one data value, with their values
being combined mathematically. The simplest of these expressions may add a pair of values,
while a more complex expression might obtain the average of three values. These operations
are performed using the familiar syntax you will have seen in applications such as Excel. The
examples below show the basic operations that can be performed…
OPERATOR PRIORITY EXAMPLE
Addition Group 4 Tag1 + Tag2
Subtraction Group 4 Tag1 - Tag2
Multiplication Group 3 Tag1 * Tag2
Division Group 3 Tag1 / Tag2
Remainder Group 3 Tag1 % Tag2
Although the examples show spaces surrounding the operators, these are not required.
OPERATOR PRIORITY
You will have noticed the Priority column in the above table. As you no doubt recall from
your algebra classes, when several operators are used together, they are evaluated in a defined
order. For example, multiplication is always evaluated before addition. Crimson implements
this ordering by means of what are known as operator priorities, with each operator being put
in a group, and with operators being applied in order from the lowest numbered group to the
highest. (Except where noted otherwise in the text, operators within a group are evaluated
left-to-right.) The default order of evaluation can be overridden by using parentheses.
TYPE CONVERSION
Normally, Crimson will automatically decide when to switch from evaluating an expression
in integer math to evaluating it using floating-point. For example, if you divide an integer
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