KROHNE Summit 8800 Vol 2 - Manual (Page 20)

20 www.krohne.com 08/2013 - MA SUMMIT 8800 Vol2 R02 en
SUMMIT 8800 GENERAL INFORMATION 02
2 .5 Specific Requirements for Meters and Volume Convertors
2 .5 .1 Numbering formats
The number formats used internally in the unit are generally IEEE Double Precision floating
point numbers of 64 bit resolution.
It is accepted that such numbers will yield a resolution of better than 14 significant digits.
In the case of Totalisation of Gas, Volumes, Mass and Energy such numbers are always shown to
a resolution of 8 digits before the decimal point and 4 after, i.e. 12 significant digits.
Depending upon the required significance of the lowest digit, these values can be scaled by a
further multiplier.
2 .5 .2 Alarms
Each of the various modules that comprise the total operating software, are continuously moni-
tored for correct operation. Depending upon the configuration, the flow computer will complete
its allocated tasks within the configured cycle time, 250mS, 500mS or 1 second. Failure to
complete the tasks within the time will force the module to complete, and where appropriate, a
substitute value issued together with an alarm indication.
For example, if a Calculation fails to complete correctly then a result of 1 or similar will be
returned, which allows the unit to continue functioning whilst an accountable alarm is raised,
indicating an internal problem.
2 .5 .3 Accountable alarm
When the value of any measurement item or communication to an associated device that is pro-
viding measurement item to the SUMMIT 8800 goes out of range, the flow computer will issue
an Accountable Alarm.
When any calculation module or other item that in some way affects the ultimate calculation re-
sult goes outside its operating band, i.e. above Pressure Maximum or below Pressure minimum,
then the SUMMIT 8800 will issue an Accountable Alarm.
When the SUMMIT 8800 issues an Accountable alarm a number of consequences will occur as
follows:
Front panel accountable alarm will turn on and Flash.
Nature of accountable alarm will be shown on the top line of the alarm log.
Alarm log will wait for user acknowledgement of alarm.
During the period of the alarm, main totalisation will occur on the alarm counters.
2 .5 .4 Optional consequences
Depending upon the configuration of the SUMMIT 8800 the following optional Consequences will
also occur:
An Entry will be made in the Audit Log, with Time and Date of occurrence.
The “Used” value of the Parameter in Alarm will be substituted by an alternative value, either
from an alternative measurement source that is in range, or from a pre-set value.
A digital Alarm output will indicate an Alarm condition.