Arrays

Arrays are represented as instances of the DynamicArrayInstance class, supporting read and write operations for both individual elements and entire arrays.

Reading Arrays

To read an entire array, use the ReadValue() method:

dynamic MAIN = symbols["MAIN"];
double[] plcDblArray = MAIN.arValue.ReadValue();

To retrieve a single element in an array, there are multiple approaches. Each of these reads the first element:

MAIN.arValue[0].ReadValue();
MAIN.arValue.Elements[0].ReadValue();
MAIN.arValue.SubSymbols[0].ReadValue();

Using MAIN.arValue[0] is recommended, particularly for multidimensional arrays, as it simplifies syntax.

Writing to Array Elements

To modify an entire array, use the WriteValue(Object) method:

MAIN.arValue.WriteValue(new double[] { 1.602, 6.022, 1.380 });

To write a single element in an array simply index into it:

MAIN.arValue[0].WriteValue(6.626);

You can also use a loop to write multiple elements at once:

double[] newValues = { 1.602, 6.022, 1.380 };
for (int i = 0; i < Math.Min(newValues.Length, MAIN.arValue.Elements.Count); i++)
    MAIN.arValue[i].WriteValue(newValues[i]);

Handling Non-Zero-Based Arrays

The IEC-61131-3 standard permits arrays with custom, non-zero-based bounds. To interact with these arrays, use their specific indices:

double plcArrayValue = MAIN.arNewValues[-1].ReadValue();
MAIN.arNewValues[-1].WriteValue(10_973_731.568160);

Array Metadata with Dimensions

The Dimensions property offers valuable metadata about an array, such as bounds, dimensions, and whether it’s non-zero-based:

int[] lowerBounds = MAIN.arValue.Dimensions.LowerBounds;
int[] upperBounds = MAIN.arValue.Dimensions.UpperBounds;
int numOfDimensions = MAIN.arValue.Dimensions.Count;
int[] dimensionLengths = MAIN.arValue.Dimensions.GetDimensionLengths();
bool isNonZeroBased = MAIN.arValue.Dimensions.IsNonZeroBased;

foreach (var dim in MAIN.arValue.Dimensions) Console.WriteLine(dim.ElementCount);

The Dimensions property is especially useful when working with complex arrays of various sizes and bounds, providing flexibility in managing diverse array structures.