Humidity, Mechanical vibration, Mounting position – HEIDENHAIN TNC 407 (243 020) Technical Manual User Manual
Page 40: 3 humidity, 4 mechanical vibration, 5 mounting position
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Cooling by blowing external air through the control cabinet to replace the internal air. In this
case the ventilator fan must be mounted so that the warm air is extracted from the control
cabinet and only filtered air can be drawn in. HEIDENHAIN advises against this method of
cooling, since the function and reliability of electronic assemblies are adversely affected by
contaminated air (fine dust, vapours etc.). In addition to these disadvantages, a filter which is
not adequately serviced leads to a loss in cooling efficiency. Regular servicing is therefore
absolutely vital.
Obstructive
elements
Heat generating
elements
Incorrect
LE
LE
Correct
2.3 Humidity
Permissible humidity:
< 75 % in continuous operation,
< 95 % for not more than 30 days p.a. (randomly distributed).
In tropical areas it is recommended that the TNC is not switched off, so that condensation is avoided
on the circuit boards. The heat generation prevents condensation and has no further disadvantages.
2.4 Mechanical vibration
Permissible vibration:
< 0.5 g
2.5 Mounting position
Note the following fundamental points on mounting:
- mechanical accessibility,
- permissible environmental conditions,
- electrical noise immunity,
- the electrical regulations which are in force in your country.