G
First of all, I think all user memory should be in battery-backed RAM. If the PLC is running on a desktop PC, then it should have a UPS. If the
application can't tolerate a UPS failure then ....do I need to state the obvious? I don't think it should be necessary to record the data table
every scan on a desktop implementation as this should be inherentlynon-critical.
How does A-B do it? My understanding: Initially all data table states are as they were at power loss (or switch from run mode) because they are in battery-backed RAM. On entering run mode, the processor does a pre-scan of the program, looking for any non-retentive outputs and
resetting them. It then begins normal program execution.
Gerry
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application can't tolerate a UPS failure then ....do I need to state the obvious? I don't think it should be necessary to record the data table
every scan on a desktop implementation as this should be inherentlynon-critical.
How does A-B do it? My understanding: Initially all data table states are as they were at power loss (or switch from run mode) because they are in battery-backed RAM. On entering run mode, the processor does a pre-scan of the program, looking for any non-retentive outputs and
resetting them. It then begins normal program execution.
Gerry
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LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc