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Error messages
Corona voltage out of range
The voltage in the unipolar corona charger is high or low. It does not necessarily mean that the instrument is
not operating properly. If you see this warning, you need to check the corona voltage in the advanced menu:
If it is larger or equal to 5 kV, and remains so constantly, then it is appropriate to clean the corona wire. If it is
between 2-3kV, this could be normal operation at low ambient pressure (i.e. you are at an alpine site or doing
airborne measurements). If it is between 2-3kV and you are at or close to sea level, then it could be due to
dirt on the counterelectrode of the charger.
In either case, you should check the display of the charging current, both with the charger on, and with the
charger off. It should be 0nA with the charger off, and 10±1nA with the charger on. If it is not 0nA with the
charger off, this means there is either dirt on the counterelectrode, or that you are operating the instrument
at condensing conditions (too high relative humidity RH) and that a
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lm of water has formed on the countere-
lectrode insulation. If you think the RH could have been too high, keep the charger turned off, and continue
to run the instrument in an environment with low relative humidity. The charging current should then go back
to 0. If it does not, you have to clean the counterelectrode.
If the charging current is below 9nA with the charger on, and the corona voltage is >= 5kV, then the corona
wire should be cleaned. Please concact the technical support and send the instrument for service.
Dirt on counterelectrode
This warning appears if the charging current is non zero when the corona charger is turned off. Follow the
instructions in the section on corona voltage out of range above.
No or bad SD-card inserted
This warning appears if you try to start recording when no SD-card is inserted in the instrument, or if the
SD-card is not formatted properly. If this warning appears despite that there is an SD-card in the instrument,
then you should reformat the SD-Card.
File system error
If this error occurs, you should reformat your SD-card
Card full
This error occurs when your SD-card has no more space to write data. You should remove it, save all data
on it, and reformat it.
General error
Contact instrument manufacturer. Email: [email protected]
The
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lter (or diffusion) stage current reached its maximal value (overrange)
At very high particle concentrations (larger than one million particles per cm3), the testo DiSCmini electro-
meter ampli
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ers might reach their maximal level. In this case, all calculated signals (number, diameter, LDSA)
are no longer correct. You can check where this occurred by pressing the
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lter or diffusion stage button on
the toolbar in the software, to quickly see whether this was just a short episode, or whether the entire mea-
surement was not reliable.
Particle levels which cause the testo DiSCmini to reach its maximal electrometer currents should be avoided
in any case – at such extreme particle levels, you will have to service your instrument very frequently! If you
plan on doing measurements at high particle levels, you should use an external dilution system.
Your instrument requires a service due to excessive dirt in diffusion stage
The testo DiSCmini collects particles in both its measurement stages, which eventually become dirty and
clog. The deposition characteristics in the diffusion stage will change with build-up of dirt, and the instrument
readings become unreliable. To protect you from using an unreliable instrument, this warning appears when
the integrated current deposited on the diffusion stage reaches a certain value , and we use it to recommend
an instrument service. You can continue to use the instrument even if this warning appears, but you have
to be aware that only the LDSA reading will then be reliable, whereas particle number and particle diameter
are no longer reliable!
