Siemens 7MB2335, Operating Instructions Manual, Page: 77 / 168

Operation
5-27
Operating instructions ULTRAMAT 23 gas analyzer
C79000-B5276-C216-03
5.9.1.2 Parameters: Measuring Ranges: Change Ranges
The full-scale values of the measuring ranges can be set in the third
and fourth lines of this dialog. They must be present within the factory
settings, i.e. if an analyzer is factory-set for a total range from 0 to
2000 mg/m
3
, modifications are only possible within this range + 3 %,
i.e. up to 2060 mg/m
3
. In addition, the full-scale value of range 1 must
not be smaller than - 3 % of the factory-set minimum permissible
range, e.g. not smaller than 388 mg for 400 mg, and not greater than
that of range 2.
5.9.1.3 Parameters: Measuring Ranges: Hysteresis
In the third and fourth lines of this dialog, you can set the value at
which the analyzer switches from one range to the other. The values
are specified in % of the full-scale value of range 1 (
MR1 ) (see
Section 5.9.1.1) .
Notice
The hysteresis is only active if the parameter Actual range has been
set to the value AR (autorange) in the dialog ”Switch ranges”.
The two switch over points should be as far apart as possible, and the
switch over point from MR1 to MR2 must be greater than that from
MR2 to MR1. The following conditions have been assumed in the
above display:
Your analyzer has two ranges: MR1 from 0 to 400 mg/m
3
, MR2 from 0
to 2000 mg/m
3
. The hystereses are defined as: MR1->MR2 at 100 %;
MR2->MR1 at 90 %.
This means:
S
If your analyzer is working in the smaller range (MR1), it switches
over to the larger range (MR2) when a value greater than
400 mg/m
3
SO
2
is measured.
S
If your analyzer is working in the larger range (MR2), it switches
over to the smaller range (MR1) when a value less than
360 mg/m
3
SO
2
is measured (= 90 % of 400 mg/m
3
).
Change ranges SO
2
MR 1:0.. 400 mg/m 3
MR 2:0.. 2000 mg/m
3
5912
Hysteresis AUTORANGE
MR1
400 mg/m
3
SO
2
MR1->MR2: 100.0% MR1
MR2->MR1:
90.0% MR1
5913