GEM80-500 Series Controller
5. Programming
(08/04)
GEM80-500 Technical Manual (T2025En)
Page 5-17
5.7.4
Data Table Sizes
Data table sizes are calculated by the controller from the user program so that if, for
example, the highest G-table address in the user program is G345 then G0 to G345
will be reserved.
Where addresses are implied (e.g. when using LOCATE and MOVE GEM 80 Special
Functions) the user must include a dummy rung or rungs to declare the highest address
When constructing the user program it should be borne in mind that memory wastage
will occur if large gaps of unused data tables are left with only high numbered and low
numbered tables used. Also, even if only one or two bits of a word are used, (e.g.
G104.1) the whole word G104 is reserved by the controller.
A GEM80 Programming Package cannot work with bit addresses above 999.15. This
restriction means for example, G999.15 can be used, but address G1000.1 cannot be
used, as individual bits cannot be accessed. However, word G1000 can be used and
words up to 30,000 can be used where access to individual bits is not required. The
limitation is on the programming tool itself where there is space only for 7 characters
on the screen.
5.7.5
Action of Clear Store on Data Tables
The CLEAR STORE command has the following effects:
(a) Removes the ladder diagram program from memory.
(b) Resets all data tables to zero except the E, F, V tables and P-table numbers 0 to
149, which have to be retained so that serial link configurations can be
maintained. This is essential for remote programming.
(c) Removes all user defined messages.
