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Using a Quantum 984 HSBY System
840 USE 106 00 January 2003 97
Defining the Transfer Area of State RAM
Additional RAM With 984 Hot Standby, you may define additional state RAM (0x, 1x, 3x, and 4x
registers) that are transferred in groups over multiple logic scans.
State RAM dialog To open the State RAM dialog, deactivate Transfer All State RAM and then use the
Options button.State RAM associated with all critical I/O also should be transferred
in every scan. Additional state RAM can be grouped and transferred over multiple
scans.
If you use the CHS instruction to configure the Hot Standby system, you are unable
to transfer any more than 12K words, even though the total amount of state RAM
could be as much as 64K words. You can limit the number of 4x registers being
transferred by selecting a block of registers as part of the nontransfer area, but you
cannot limit the number of 0x, 1x, or 3x registers in the transfer area.
Note: The command register must be located in the area of state RAM which is
transferred in every scan.
State RAM
State RAM
Number of References to Transfer
OK Cancel Help
Transfer: User Defined
Coils (0xxxx):
0
Discrete Inputs (1xxxx):
0
Input Regs (3xxxx):
0
Output Regs (4xxxx):
0
Additional State RAM
Number of References to Transfer
Coils (0xxxx): 0
Discrete Inputs (1xxxx):
0
Input Regs (3xxxx):
0
Output Regs (4xxxx):
0
Transfer Additional State RAM Extra Transfer Time (1-255): 1
Concept shown