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Emerson Process Management GmbH & Co. OHG7-8
X-STREAM X2
Instruction Manual
HASX2E-IM-HS
02/2012
Calibration gases...
Tol.Check: Off
Hold on cal: On
Purge time: 15 s
7.4.1 Preparing Calibrations
Example:
Measuring range: 0 ... 50 %
Zero gas: 0 %
Span gas: 50 %
Situation:
Due to a fault zero gas is supplied to carry
out a span calibration, instead of span gas.
Tolerance check disabled (Off):
The analyzer calibrates the span with the
wrong gas resulting in an analyzer out of tune.
Tolerance check enabled (10%; AutoOff):
Starting a span calibration with zero gas
connected instead of span gas, the analyzer
gives an error message and stops calibrating
because the measured (expected span gas)
value differs more than 10 % from the upper
measuring range limit.
By default the option "Tol.Check" (tolerance
check) is disabled (Off).
So tolerance check helps avoiding calibrating
with a wrong gas applied (e.g. starting a span
calibration while zero gas is owing) resulting
in an instrument out of tune (see example to
the left side).
With tolerance check enabled (10%) during
calibration the analyzer checks that the en-
tered (setpoint) values for zero gas and span
gas are reasonable compared to the currently
owing calibration gas. If this gas concen-
tration differs more than 10 % of measuring
range from zero gas (during zero calibration)
or span gas setup (during span calibration),
calibration is aborted and a maintenance
request alarm is set (LED and optional relay
output). Resetting the alarm requires to per-
form a valid calibration or to conrm it within
the CONTROL - ACKNOWLEDGEMENTS..
screen.
The 3rd option (AutoOff) has the same func-
tionality as 10% except that the maintenance
request is reset after 2-3 minutes.
There are still situations when tolerance check
must be disabled, e.g. when calibrating after
changing the span gas concentration. In this
cases select Off.
Note!
Unacknowledged maintenance requests are
stored even if the instrument is switched off
and on again!
In addition: If, for example, a calibration was
aborted because of a tolerance check, the
maintenance request is active. If the operator
does not acknowledge the request and per-
forms a new calibration, now with disabled
tolerance check, the earlier maintenance re-
quest is stored and re-activated again, when
the tolerance check is enabled somewhere
in the future!