Enclosure specications for accommodation of intrinsically safe overvoltage suppressors in
potentially explosive areas
Overvoltage suppressors in hazardous areas must be installed in a metal enclosure or an
enclosure certied for the device application. If the application is in areas with combustible dust,
enclosure degree of protection IP6X shall be selected.
• Zone 1: Enclosure with degree of protection Ex e (increased safety)
• Zone 2: Enclosure with at least IP54 (with manufacturer's declaration for Zone 2)
• Zone 21: Dust-tight (certied) enclosure with degree of protection of at least IP6X
• Zone 22: Dust-tight (certied) enclosure with degree of protection of at least IP5X
Testing the overvoltage suppressors used
An overloading of the overvoltage suppressor of the Blitzductor BXT ML4 BD EX 24 series can be
detected by the implemented LifeCheck technology using the DRC LC M3 testing device (Article
number 910 653) before the nal destruction. Use of this test device is only permitted outside
the hazardous zone. As before, these lightning conductors have the fail-safe function that
generates a signal-type interruption when the overvoltage suppressor is irrevocably destroyed,
thus placing the downstream system out of operation but protecting it from further
overvoltages.
A.6 HART operating data records
A.6.1 HART command interface
Data records
The HART commands are sent as so-called external HART requests from the client (e.g. PDM) to
the connected eld device using data records. The response of the eld device is made available
again in the system via data records.
The HART communication may only be handled by one client per channel. If a channel is handled
by several clients, the response made available by the I/O module cannot be allocated to one
client with certainty. The I/O module does not support client management.
Rules
• After having written a request data record, a client must read the response data record before
it may write another request data record.
• The client can evaluate the "processing status" in the response data record: If the "processing
status" indicates "successful" or "error," the response data record contains current response
data or error indications, respectively.
Appendix
A.6 HART operating data records
ET 200iSP
Operating Instructions, 11/2022, A5E00247483-AK 451
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