Campbell Hausfeld SDM-CVO4 Manuel D’Utilisation

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Instruction Manual 
Where the SDM-CVO4 is going to be used in applications where the potential 
difference between the datalogger and the output terminals exceeds 50 V RMS 
AC, 74 VDC then careful consideration has to be taken to ensure safe operation 
and compliance with local safety regulations. For such applications Campbell 
Scientific does not supply the device as a stand-alone device which will meet all 
safety requirements. The SDM-CVO4 is supplied as a component for the user to 
install in a system that is, itself, designed to comply with such regulations. The 
following guidance is given to help users meet the requirements of such 
regulations. 
The SDM-CVO4 is designed such that the internal safety barrier meets the 
requirements of BS EN 61010-1 (similar to IEC 950). However, the method of 
wire connection and earthing facilities prevents the unit being claimed as 
compliant with such standards, when supplied as a stand-alone unit. 
To meet the safety requirements of most countries, wires carrying hazardous 
voltages, terminated in screw terminals must be housed in an enclosure requiring a 
tool to open it, and the enclosure must have international symbols on the outside 
warning of high voltages. An additional warning label, in the local language, may 
be required stating that the source of hazardous voltage must be turned off before 
the enclosure is opened. 
The exact nature of the enclosure is covered by the standards, but an enclosure 
designed to house electrical equipment will usually meet the requirements. 
Campbell Scientific's ENC 12/14 or 16/18 enclosures meet these requirements if 
fitted with a padlock and with the correct labels on the door. 
It is also necessary to ensure that metal parts on the outside of the enclosure that 
might come in contact with active high voltage circuits are connected to a safety 
ground. The ground lug of Campbell Scientific enclosures is the main issue for the 
above enclosures, but this would, in any case, normally be the point of contact to a 
good ground point. 
Cables that connect to the output of the SDM-CVO4 should have adequate strain 
relief at the point of exit from the enclosure, and the cable and any connectors 
used should be rated to a high enough voltage and assembled in a safe fashion. 
If possible, the external device which is operating at a high voltage relative to 
ground should be configured with an earth leakage breaker system to disconnect it 
from the voltage source in the event of a breakdown of the insulation in the 
system causing a leak to ground. 
With a system made to the above requirements the maximum recommended 
continuous operating voltage between the datalogger and input is 240 VAC. This 
value is derived from the voltage rating of the terminal blocks used and an internal 
suppression capacitor (see below). 
The unit is designed to withstand a transient flash test of 1500 V RMS AC, for 
two seconds. However, you need to be aware of some aspects of the design which 
can influence the results of such a test if made. 
a)  To help suppress emissions of electromagnetic interference the isolation 
barrier is bridged by a 1nF, class ‘Y’ safety capacitor. This is rated to 
withstand a 2700V, 2 second flash test, but will fail if exposed to 
voltages in excess of 240 V RMS for long periods. 
b)  To provide protection from transients and static for this capacitor and the 
opto-isolation component that bridges the barrier, there is a spark gap 
across the barrier that has a 2500 VDC nominal breakdown voltage. If 
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