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Using a Quantum 984 HSBY System
98
840 USE 106 00 January 2003
Hot Standby
Dialog
Using the Hot Standby dialog, you have a great deal more flexibility in determining
how much or how little State RAM gets transferred. You also can manage how much
gets transferred in all scans and how much gets transferred in pieces over multiple
scans.
The parameter you select in the Transfer field of the State RAM determines the
flexibility you have in defining your state RAM transfer area. You may choose from
two options:
12K
User Defined
12K Option The 12K option mimics the CHS instruction. It gives you a predefined state RAM
transfer area with a predetermined maximum of each reference data type to be
transferred. The predefined transfer area consists of the following:
All the 0x discrete outputs in state RAM up to a maximum of 8192, including their
associated histories.
All the 1x discrete inputs in state RAM up to a maximum of 8192, including their
associated histories.
If the total number of registers (3x and 4x combined) implemented in state RAM
is 10 000 or less, then all the registers plus the up/down counter history table.
If the total number of registers (3x and 4x combined) implemented in state RAM
is greater than 10 000, then 10 000 registers transfer in accordance with the
formula described in
System Scan Time, p. 33
.
If you choose the 12K option, the State RAM and Additional State RAM area
become irrelevant. You can not customize the transfer area or transfer additional
data in groups over multiple scans. Any entries in these fields are ignored.
Note: The remaining entry fields of the dialog may or may not be used depending
on which one of these two parameters you choose.
Note: No matter which option you choose, remember that the command register
must be included in the block of registers transferred on every scan.