Product Overview GEM80-400
Page xxii ALSPA GEM80-400 SERIES CONTROLLERS TECHNICAL MANUAL Issue 3 04/99
indirectly using the CLOCK special function, S55. The Real Time Clock is Year 2000
compliant
2.3. RAM
The GEM
80-400 Processor Module provides as standard:
RAM to store and execute a 20000 instruction user Ladder program +
RAM to provide up to 30000 data tables +
RAM to store up to 30000 bytes of User Messages (P-table messages).
RAM to store up to 64K of IMAGEM formats ( 4 IMAGEM pages )
The user messages are stored in an area of on-board RAM separate to the data
tables, in order to provide more data table space to the user program., and to
avoid the complication in the User Programme caused by storing user messages
in Off - Line memory. Otherwise the user messages may be created, used, saved
and loaded in the same way as the GEM
80/160, GEM
80/310 and GEM
80-400
Controllers..
The GEM80-400 Processor Module also provides 64K ( 4 IMAGEM pages ) of
IMAGEM format storage RAM which will allow IMAGEM applications to be used
for smaller graphics applications without the need to purchase additional RAM
modules. This saves expenditure and space.
2.4. Input Output Systems
All GEM
80-400 Series Controllers allow some I/O to be used in the controller
subrack.
2.4.1. Basic and Verification I/O
The GEM
80-400 Controller provides 256 bits of Basic I/O and up to 1024 words of
Verification I/O. Verification I/O Expander Modules may be used to provide
additional Basic I/O capacity.
The Basic I/O addresses supplied directly by the controller (as opposed to via
Verification I/O Expanders) are set to addresses A/B0 to A/B15. A/B addresses
above these are used to access Verification I/O Modules or Basic I/O Modules
via Verification I/O Expanders.
Faults detected during transfers to and from Basic and Verification I/O Modules
will set bits in the F-tables and do not automatically trip the controller. This allows
the user program to determine if a particular transfer fault is critical to the
application and if necessary to shut down in an orderly fashion.
2.4.2. Fast I/O
The GEM80-400S version of the controller provided five slots of Fast I/O in place of
the Basic or verification I/O modules. One of these slots is dedicated to the Fast
I/O Driver so that four slots are available for Fast I/O Modules. No further
extension of the fast I/O capacity is possible with the 400S version. If more that
four Fast I/O Modules are required then the GEM80-400 Enhanced Controller
must be used and additional Fast I/O subracks fitted.
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