GE VersaMax PLC, Руководство пользователя

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9.1.2 Bit Memory References
Each bit memory address (reference) is on a bit boundary. Data is stored in bit memory as
represented below. The illustration shows 160 individually-addressed bits, with address 1
in the upper left and address 160 in the lower right.
0
0
1
1
0
1
1
1
1
0
0
0
1
1
1
1
1
1
0
0
1
1
1
0
0
0
0
0
0
0
1
1
1
0
1
0
1
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
1
1
0
1
1
1
1
1
0
0
0
1
1
1
1
0
0
0
0
1
0
0
0
0
0
1
1
1
0
0
1
0
1
0
1
1
1
0
1
1
0
1
0
1
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
1
1
1
1 2 3 4 5 6 7 8
... 160
addresses
The PLC uses six types of references for data stored in bit memory.
%I
Normally used for discrete inputs, and viewable in the Input Status Table.
%Q
Normally used for physical output references, and viewable in the Output Status Table. A %Q
reference may be either retentive or non-retentive, depending on its use in the program.
%M
Normally used to represent internal references. A specific %M reference may be either retentive
or non-retentive, depending on its use in the program.
%T
Used for temporary references that can be used many times in a program. Data with %T
references is not retained through loss of power or RUN-TO-STOP-TO-RUN transitions. %T
references cannot be used with retentive coils.
%S
System status references, which have specific predefinitions.
n %S, %SA, %SB, and %SC can be used for any type of logic contact.
n %SA, %SB, and %SC can be used for retentive coils.
n %S can be used as inputs to functions or function blocks.
n %SA, %SB, and %SC can be used as inputs or outputs of functions and function blocks.
%G
Used for Global Data. Data in %G references is retained through power loss. %G references can
be used with contacts and retentive coils, but not on non-retentive coils.
9.1.3 Transition Bits and Override Bits
%I, %Q, %M, and %G references have associated transition and override bits.
%T, %S, %SA, %SB, and %SC references have associated transition bits only.
The CPU uses transition bits for transitional coils. When override bits are set, the
associated references can only be changed from the programmer.
Program Data GFK-1503E User Manual 115
For public disclosure