Elster Instromet TRZ2 Mode D'emploi page 16

Absolute ENCODER S1 (optional)
– This has the same features as index S1.
– Can be used as main index on gas meters.
– Available as a top-mounted unit (transmitter unit) on
meterswithmechanicalindexdrive(MI-2).
– The encoder is suitable for connection to a series-
connected additional device (volume corrector, data
logger or bus system) in potentially explosive atmos-
pheres(seetable:TechnicalData).Adeviceconnected
totheterminalboxmustfeatureatleastthefollowing
approvalasanassociatedapparatusforthis:
[ Ex ia IIC ]forversionwithNamurinterface,
[ Ex ib IIC ]forversionwithSCR/SCR+interface,
[ Ex nA [ic] IIC ]forZone2installation(Namur/SCR/SCR+interface).
 TheversionwithM-BUSinterfaceisnotATEXapproved.
Connection of the Absolute ENCODER S1 unit to the mechanical index drive of the meter
– Connect the connector of the top-mounted unit to the mechanical index drive of the driving
unit(e.g.MI-2,ensurethesteeldiscisremovedfromtheconnector).
– Usealockingscrewtosecuretheencodertop-mountedunitagainstpullingout.
– Thelockingscrewmustbelead-sealedforapplicationsrequiringmandatorycalibration.
Connection of the encoder
– Use only a screened
(DIN EN 60079-14) to connect the
encoder and ensure that the pin
assignment is correct (see sticker
next to the cover of the terminal
box).
– When connecting the Namur interface, ensure that the 2-wire connection has the correct
polarity. The M-Bus and SCR/SCR+ interfaces are independent of the polarity.
– Itispossibletoapplyscreeningandtorunacabletothemeterhousingorthepipe.Make
suretocheckinadvancethatthegroundingsystemusedallowsgroundingonbothsides
(ground loops and potential difference in grounding).
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