GE 90-30 PLC, User Manual

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4-14 Series 90™-30 PLC LONWORKS® Bus Interface Module User's Manual – June 1997 GFK-1322A
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SNVT Size
Size of the network variable in 8-bit bytes. This is the variable size as viewed from the
LONWORKS network.
PLC Size
Number of PLC register addresses needed to hold this variable or a single element if the
variable is an array. In the case of discrete registers (%I and %Q) this number represents
the number of bits required. For analog registers (%AI and %AQ) this is the number of
16-bit register locations needed for this variable.
Array Size
Array size is the number of array elements defined for the variable. To change, highlight
the value and type new value over the old. The program will recalculate the variable
length. An array of size zero represents a single normal variable with no array indexing.
An array of size one is treated as a single variable, but includes array indexing.
Variable Array Size Resulting Names
NVI_MyVar 0 NVI_MyVar
NVI_MyVar 1 NVI_MyVar[0]
NVI_MyVar 2 NVI_MyVar[0]
NVI_MyVar[1]
NVI_MyVar i NVI_MyVar[0]
NVI_MyVar[1]
.........
NVI_MyVar[i-1]
Length
Length is the total number of register locations used by the currently defined variable. It
includes all elements of an array.
SCPTs
Depending on the direction of the current variable, one of the following configuration
parameters can be edited from this screen. If the variable is an input, the maximum
receive time parameter is displayed. The maximum send time and minimum send time
parameters apply to output variables. SCPTs are NOT defined in the .XIF file created for
the module configuration. SCPTs are contained in the Value File which must be
downloaded to the module in a separate download operation.