62
3.19.1 97BReasons for instability:
3.19.1.1 Too low deviation value
One reason for the above message is that the deviation value in the configuration
window is too low, so that a higher value should be entered. The levels of noise of
all cells are not necessarily identical. Longer cells have normally higher noise than
shorter ones and the sensors themselves have noise level deviations between
exemplars.
3.19.1.2 Too high noise
One more reason could be exceptionally high noise. The base lines and the level
of their noise can be seen on the screen when clicking on the base lines icon (with
three waves).
The most common reasons for too high noise are:
– The infrared sensor.
– The pre-amplifier,
– A fault on the circuit board IRC-1.x where x can be 1,2, or 3.
– At least one IR source is defective.
– The microcontroller board.
– The power supply fluctuates.
In case of a module (rack) of more than one IR-cell, mostly only one of the base
lines has too high noise while the others have noise in normal range. In order to
localize whether the noise is created by the sensor, preamplifier or the
corresponding section of the IRC board, interchange the preamp connector of the
noisy range with another one on the IRC board. If the noise moves to the other
range on the PC screen (base line color), this means that the noise is created by
the sensor or preamplifier.
In this case replace first the sensor as the more probable reason and if this doesn't
help, replace the preamplifier.
NOTE
Don't forget to connect the interchanged connectors to the original position again.
• If the noise is created by the IRC board, change it.
Remark: In such case, theoretically, the noise could be created by the
corresponding analog input of the microcontroller board however this possibility is
very unlike.
3.19.1.3 Too high drift
Another reason for report of instability is a too high drift of at least one cell, so that
the signal of one cell reaches the end of the set window (mV).
A drift can be due to temperature changes of the IR cell. It happens when the cell
temperature is still not stable after switching on the power. When switching on the
power after long break so that the cell is cold, allow the cell at least 30 minutes to
stabilize the temperature. This has to be taken into consideration when checking
the base line stability.
When starting the oxygen flow (power switch on position 2), the cell takes about 5
minutes to stabilize when restarting the oxygen flow after long time without flow
(but with uninterrupted power).
Pos: 5.43 /0 020 Über sc hrif ten /ELT RA 1.1 Über sc hri ften /11 F ur nac e op ens wit h del a y aft er t he end of a nal ysis ELT RA @ 6\mod_1368703238004_9.docx @ 41143 @ 222 @ 1
3.20 33BFurnace opens with delay after the end of analysis
Pos: 5.44 /0 010 ELTR A/ 0015 s ervic e_i nstr uc tio ns/C S-800 _Ser vice/ 0015 F ehler/ 01951 0 Modul Furnac e ope ns with del ay ELTR A @ 6\mod_1377688610559_9.docx @ 46735 @ 22444 @ 1
There can be two different reasons for this.
1. One reason is that this delay is set in the software. The software provides
the possibility to set a time to delay the furnace opening after the end of
analysis. This is occasionally required for samples creating harmful oxides or
To Next Page
Loading...
Need help?
General
