GE GFK0579B Scanner User Manual


 
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59Chapter 4 Configuration with Logicmaster 90–70
I/O Map
The I/O map represents the boundaries of the I/O references assigned to the remote
drop which will be scanned by the central PLC. Before any modules are configured,
the I/O map begins at the next available reference in each data type, based on the PLC
configuration, and each reference type has a length of 0. You can change the reference
starting addresses and enter lengths manually, or you can use automatic I/O mapping.
The best method to use will depend on your application. If all I/O in the remote drop
will be scanned by the central PLC and no future additions to the remote drop are
planned, it is easiest to use automatic I/O mapping. However, if some I/O in the remote
drop will not be scanned by the central PLC, you may prefer not to have the software
automatically configure the I/O map. Details are on the following pages.
The beginning configured reference for each data type. Initially, the
I/O map shows the next available reference in each data type, based on
the PLC configuration. If Auto I/O Map is ON, the software ensures
that all configured I/O will be scanned by the central PLC by adjusting
the I/O map. The first configured I/O module of a given data type will
have a starting reference offset that matches the offset of the I/O map.
Series Six or Series Five PLC: Reference Assignment You MUST
use a Hand–held Monitor to change a Series Six or Series Five
reference previously configured using either Logicmaster 90–70 or a
Hand–held Monitor. You also must use an HHM to assign a reference
in register (rather than I/O) memory. For a Series Six or Series Five PLC
system that uses I/O table references, a previously–unconfigured
Remote I/O Scanner will accept a reference entered here. It will be the
reference for the first data type (in the sequence listed above) for
which you enter a non–zero length. For example, if the remote drop
has only analog input and output boards, the data lengths for %I and
%Q would be 0. You would enter a data length for %AI and %AQ.
The beginning reference entered for %AI would become the beginning
Series Six or Series Five reference for the remote drop.
The amount of data of each type to be exchanged with the PLC. For %I
and %Q memory, length is in bits (points). For %AI and %AQ
memory, length is in words (each word is two bytes). If Auto I/O Map
is ON, it is not necessary to enter lengths in the I/O map; within the
limits given below, the software will increment the lengths as you
configure I/O modules in the remote drop.
Data Length Limits Each remote drop transfers any mix of discrete
and analog inputs up to 128 bytes, and any mix of discrete and analog
outputs up to 128 bytes. These limits reflect the maximum amount of
data that can be sent on the Genius bus in a single transmission. Bit
memories (%I and %Q) are assigned on byte boundaries. Reference
limits for the Remote I/O Scanner are listed below. Reference limits for
the host may not necessarily be the same. Whichever is smaller
determines the practical limits of the configuration.
Memory Type References
Available
Maximum
Quantity
%I 12K up to 1024 bits
%Q 12K up to 1024 bits
%AI 8K up to 64 words
%AQ 8K up to 64 words
Ref Addr
Length