GE 90-30 PLC, User Manual

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GFK-1322A Chapter 4 Configuring the LBIM 4-17
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Table 4-2. Network Variable Fields in the Network Variable Editor
Field Description
Name The name of the network variable as seen from L
ON
W
ORKS
. Enter a name to
create a new network variable.
Reference Type To change this field, click the scroll bar.
Discrete — type %I or %Q, depending on direction
Register — type %AI or %AQ, depending on direction
Only network variables of type SNVT_switch or SNVT_lev-disc can use the
discrete reference type.
Network Variable
Direction To change this field, click the scroll bar. The choices are:
Input — from L
ON
W
ORKS
to the PLC
Output — from the PLC to L
ON
W
ORKS
Array Size Used to create network variable arrays. Arrays are mapped to subsequent PLC
references. For example, an array of 12 discrete, input, SNVT_switch network
variables starting at reference %I9 would be mapped to %I9 through %I20. For
network variables that are mapped to registers, the network variable data is
packed into the subsequent registers.
Reference Address The reference address specified must be within the PLC reference type blocks
configured for the LBIM. Also, the address cannot be the same as other network
variables.
Valid Bit Address The address of the %I reference type that will be the valid bit for the network
variable.
Default Specifies the default value the PLC will assume for the network variable if a
network error occurs. To change this field, click the scroll bar. The choices are:
Hold — maintain the last value when an error occurs
Zero — set the value to zero when an error occurs
Type Specifies the network variable data type. To change this field, click the scroll bar.
The choices are:
Standard Network Variable Types — choose from the list of SNVTs
user_defined — allows custom network variables (This is the final
choice on the list of SNVTs.)
Size The number of bytes used by the network variable. You can modify this field only
if the network variable type is user_defined.
Length The total length, in bytes, of the network variable or network variable array. You
cannot modify this field.