Delta OHM HD3406.2, User Manual, Page: 22 / 44

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WARNINGS AND OPERATING INSTRUCTIONS
1. Do not expose the probes to gases or liquids that could corrode the material of the sensor or the
probe itself. Clean the probe carefully after each measurement.
2. Do not bend the probe connectors or force them upward or downward.
3. Do not bend or force the contacts when inserting the probe connector into the instrument.
4. Do not bend, deform or drop the probes, as this could cause irreparable damage.
5. Always select the most suitable probe for your application.
6. Do not use probes in presence of corrosive gases or liquids. The sensor container is made of
AISI 316 stainless steel, while the contact probe container is made from AISI 316 stainless steel
plus silver. Avoid contact between the probe surface and any sticky surface or substance that
could corrode or damage it.
7. Above 400°C and below –40°C, avoid violent blows or thermal shocks to Platinum temperature
probes as this could cause irreparable damage.
8. To obtain reliable measurements, temperature variations that are too rapid must be avoided.
9. Temperature probes for surface measurements (contact probes) must be held perpendicular
against the surface. Apply oil or heat-conductive paste between the surface and the probe in or-
der to improve contact and reduce reading time. Whatever you do, do not use water or solvent
for this purpose. A contact measurement is always very hard to perform. It has high levels of
uncertainty and depends on the ability of the operator.
10. Temperature measurements on non-metal surfaces usually require a great deal of time due to the
low heat conductivity of non-metal materials.
11. Probes are not insulated from their external casing; be very careful not to come into contact with
live parts (above 48V). This could be extremely dangerous for the instrument as well as
for the operator, who could be electrocuted.
12. Avoid taking measurements in presence of high frequency sources, microwave ovens or large
magnetic fields; results may not be very reliable.
13. Clean the probe carefully after use.
14. The instrument is water resistant and IP66, but is not watertight and therefore should not be
immersed in water without closing the free connectors using caps.
The probe connectors must
be fitted with sealing gaskets. Should the instrument fall into the water, check for any water in-
filtration. Gently handle the instrument in such a way as to prevent any water infiltration from
the connectors' side.
Notes on conductivity measurement
The service life of a cell can be unlimited, provided that the necessary maintenance is performed
and that it does not break. Some of the most frequent problems and their possible solutions are re-
ported below.
Measurement of conductivity different from the expected value . Check that the cell used is suit-
able for the measurement range. Check that the cell is not dirty, that there are no air bubbles inside
it. Calibrate again using the appropriate standard.