4-3
4.7 Electrical Connections
HiD isolators are plug-in devices, to be connected to a Termination Board by two multi-pole connectors. Therefore,
all electrical connections (supply, control room and field) are made at the Termination Board level.
All electrical connections and wiring must comply with the Intrinsic Safety standards and installation rules
applicable in the country of installation. Failure to adhere to these rules can defeat the purpose of Intrinsically Safe
unit and result in risk of a fire or explosion in the hazardous location.
Please refer to the Termination Board User Instruction Manual (IM-ENG 112/GB) for a more detailed
discussion, ELCON WILL NOT BE HELD RESPONSIBLE FOR ANY DAMAGE CAUSED WHEN THE
PROCEDURE DESCRIBED IN THE MANUAL IS NOT FOLLOWED.
4.8 EMC Guidelines
All HiD isolators have been carefully tested to ensure the compliance with the specified EMC standards. The
verifications were either carried out by certified test houses or internally by using equivalent test set-ups.
Comprehensive reports were always used to register test results.
The compliance with the applicable generic standards is not however such to always guarantee the proper unit
behaviour regardless of the operating environment and of the specific system configuration. The following
guidelines are useful minimise this type of risk:
• all the units in the system should comply with the mandatory EMC standards;
• the HiD emission level is intrinsically low, no special care should be required;
• in a normal industrial environment, screened cables are not mandatory;
• when very strong radiated fields are expected, properly grounded screened cable are recommended;
• use proper shield grounding techniques, avoid ground loops as much as possible;
• supply lines voltage dips outside specifications should be avoided;
• for AC connected units, the mains should be de-coupled from relevant, inductive switching loads;
• don’t run connection cables side by side with potentially noisy system wiring;
• use proper system level grounding end earthing techniques.
4.9 Heat Dissipation and Thermal Behaviour
Operating Temperature definition
Elcon Isolators are small, highly integrated electronic devices, which permit high-density installations. Although
Elcon products benefit from special low-power design techniques, it can be necessary to take into account the
internal power dissipation when dealing with operating temperature issues.
For this reason, operating temperature limits are specified for modules in a “reference condition”, and namely:
- open air mounting, no ventilation;
- wall-mounted, 8 position TB fully equipped with identical units;
- horizontal mounting;
The temperature measured immediately beneath the group of units is then applicable operating temperature.
Operating Temperature range
The range specified for Elcon products is generally 0–60 °C, with 0.01%/°C stability for analogue models.
Derating could however apply for certain models, please check the relevant specifications.
The operating temperature limits are maximum ratings. When they are passed, specifications are no more
guaranteed and permanent faults may occur. Continuous operation near the upper temperature limit is not
recommended because it reduces the product life.
Operating Temperature assessment
This section provides some general guidelines to estimate the units operating temperature in a typical application.
When you can keep a reasonable safety margin, no thermal analysis is generally not required. In the following, the
assumption is that the units are mounted within a cabinet.
Recommended temperature limits:
- ambient temperature (outside the cabinet) not higher than 40 °C;
- average air temperature (within the cabinet) not higher than 55 ° C;
- air temperature out from the units venting openings not higher than 80 ° C;
When you think it likely that these limits are passed for extended periods of time, you should perform a more
careful thermal analysis, possibly considering the MTBF implications.
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