User Manual

CM2U8567E / 04.1999 VISONIK DCS Functions and System Messages VVS18 Siemens Building Technologies
2-10 Function BOOT Landis & Staefa Division
2.3.1.2 System Halt
All process data from VISONIK are continuously written on hard disk. This means that
loss of data is kept to a minimum if there is a power supply failure.
However, data traffic with hard disk is not possible in byte units, rather in packets of
1000 bytes (octal). This method of packet transfer has the disadvantage that it must not
be interrupted.
For this reason a VISONIK system must N O T be stopped with the computer console's
HALT keyswitch or through switching off power. In such cases a data transfer could be
interrupted which can lead to corrupted data.
Recommendation:
If the power must be switched off e.g. for fitting new hardware, the computer must
always
be first shut down with Function BOOT,D. Only then can the power be switched
off.
2.3.1.3 System Start-up
Start-up of VISONIK depends on how it was previously halted.
For example
–
In commissioning
–
Restart after program take-over, e.g. BOOT,W
If a system has already been in operation then both Operating System software and
VISONIK software exist on hard disk. This means the system can "boot" automatically
from disk DU0:.
The following sequence takes place
When "booted", the Operating System software is loaded to main memory and the start
phase is initiated.
In this phase all important system sub-units such as Rings, Substations, Printers, and
Terminals are initialised and reported if faulty.
At the finish of Ring initialisation (=SDLC Controller Test and connection of EKLs to their
Rings!) a so-called general acquisition (poll) of EKLs is actioned.
This is a request from the Server computer for the current status of all EKLs. The
returned information is compared with that stored on disk before the system was halted
and if necessary processed (for example, printout of messages, initiate Reactions, etc.).
Switch and position commands are reset by 'remote loading' if the system detects any
differences between "Actual (real)" and "Setpoint" values.
If a switch command has its parameter FBX=NO (= No Output!) then accordingly, no
new command is issued.
Exception: