Flow Switch Version Vh; Reed Contact - Switching Of Inductive Or Capacitive Loads; Exclusion Of Liability - SIKA VH Série Notice D'utilisation

VH... / VK...
1.1.1 Flow switch version VH...X
The Flow switches for application in explosion-hazardous area have an "X" at the end of the
article number ( type plate). They have been subjected to an ignition hazard assessment
according to DIN EN 13463-1: 2002 and correction 1: 2003 and do not have potential sources
of ignition. They are, therefore, not subject to directive 94/9/EC.
The switching unit is a simple electrical device for connection to a certified intrinsically safe
circuit in accordance with DIN EN 60079-11: 2007. The effective internal inductances and ca-
pacities are negligibly small.
The flow switch series VH...X are designed for application in explosive atmospheres. The igni-
tion energy of the explosive atmosphere should not fall below 60 μJ.
Please observe the following separation of zones:
The design of the flow switch VH...X allows a potentially explosive atmosphere (zone 0) to ex-
ist permanently, over a longer period or frequently within the pipework in which the paddle is
located.
In normal operation, there should only be an occasional potentially explosive atmosphere
(zone 1) outside the pipework where the flow switch connection is located. A manufacturer's
declaration is available.

1.1.2 Reed contact - Switching of inductive or capacitive loads

CAUTION! Destruction or damage of reed contact!
Take notice of the max. contact loads mentioned on the specification plate!
The max. contact loads mentioned on the type plate (switching voltage, switching current and
switching capacity) refer to pure ohmic loads and may not be exceeded under any circum-
stances.
High voltage and current peaks can occur, particularly when switching inductive or capacitive
loads (e.g. relay coil, capacitors). Even if the overload is brief, this can destroy (welding the
contacts) or damage (reduced lifespan) the reed contact.
 Only use protection methods which be appropriate and checked.
Protection method when electrical connection of reed contacts:
The following protective circuits are basically possible: current limiting resistors, RC cir-
cuits, freewheeling diodes, suppression diodes, varistors or a combination of these.
Please verify the effectiveness of the chosen protection method in accordance with the spe-
cific loads involved.

1.2 Exclusion of liability

We accept no liability for any damage or malfunctions resulting from incorrect installation,
in-appropriate use of the device or failure to follow the instructions in this operating manual.
Technical changes reserved
Device description
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