Siemens Maxum II Manual page 12

System Functions
3.2 Functions
If a calibration is scheduled, it is put in queue. The calibration then initiates after completion
of the current cycle, and when the appropriate time has passed for the calibration blend to flow
through the sampling valve. If shift average reports are to be calculated and printed, the report
should include all cycles, which started, or sampled, during the specified shift. To have data
available for calculation, a wait period may occur for completion of the current sample analysis.
Analysis Cycle Clock
The Analysis Cycle Clock (ACC) is another clock that provides the timebase for all events
associated with the actual chromatograph analysis cycle. SYSCON cycle clocks can be
configured to provide timed event resolutions of 0.1 second, 0.01 second, 0.01 minute, or 0.001
minute. This is the Sensor Near Electronics software module (SNE) Event Table Scan Rate,
which is independent of detector scan rates.
All SYSCON cycle clocks and associated SNE MUST BE of the same second or minute time
units. This clock works in conjunction with the Stream Sequence Table and associated sample
stream enable and skip flags. This controls sampling order and analysis of process streams
connected to the analyzer.
Accessing SYSCON
The clock cycle RUN mode is controlled by the SYSCON upon command from SNE. When a
clock cycle is started, the associated SNEs, for that method, initiate a mirror of the cycle clock.
The SNE clock is the true basis of timed events relating to the Gas Chromatograph oven valve
timing, detector digitization and peak integration.
SNE Cycle Clock
The SNE cycle clock is used to schedule the following events.
● Analysis valve timing
● Detector balances
● Temperature set points start and stop for
PTGC
Note
Scheduled solenoid valve events cause Solenoid Valve Control Module (SVCM) hardware to
be activated within 5 milliseconds of stated cycle time. Any scheduled pressure set-point
adjustments are transferred to the actual Electronic Pressure Control Module (EPCM)
hardware within 5 milliseconds.
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● Cycle Reset
● Pressure set point timing for pressure
programming
● Analysis result calculations and reporting
Maxum edition II Analyzer General Maintenance
Manual, August 2018, A5E42019842001