Emerson PACSystems RX3i - Page 66

PACSystems™ RX3i and RSTi-EP CPU Reference Manual Section 3
GFK-2222AK October 2019
CPU Configuration 58
Md = 3 or 4. The number of bits is multiplied by 3 to keep track of the force, transition,
and value of each bit. If point faults are enabled, the number of I/O discrete bits is
multiplied by 4.
Mw = 2 or 3. There are two 8-bit bytes per 16-bit word. If point faults are enabled, the
number of bytes is multiplied by 3 because each I/O word requires an extra byte.
3.2.6.2 Calculation of Total User Memory Configured
The total amount of configurable user memory (in bytes) configured in the CPU is
calculated as follows:
Total managed memory (bytes)
+
total reference words × (2 bytes/word)
+
[if Point Faults are enabled] (total words of %AI memory + total words of %AQ
memory) × (1 byte / word)
+
[if Point Faults are enabled] (total bits of %I memory + total bits of %Q memory) / 8
bits/byte)
Note: The total number of reference points is considered system memory and is not
counted against user memory.