Elster Instromet RABO, Instruction Manual

Page: 19 / 132

Elster-Instromet
17
73021678d © Elster GmbH • All rights reserved • Subject to technical modification
English
16. Absolute ENCODER S1D
- This has the same features as index
head S1D.
- Can be used as main index on gas meters.
- Available as a top-mounted unit (transmitter
unit) on meters with mechanical index drive
(index head version MI-2).
- The encoder is suitable for connection
to a series-connected additional device
(volume corrector, data logger or bus system)
in potentially explosive atmospheres (see table: Technical Data). A device
connected to the terminal box must feature at least the following approval as
a related equipment for this:
[ Ex ia IIC ] for version with Namur interface,
[ Ex ib IIC ] for version with SCR and SCR Plus interface.
[ Ex nA [ic] IIC ] for zone 2 (Namur / SCR / SCR+).
The version with M-BUS interface is not ATEX-approved!
Connection of the Absolute ENCODER S1D 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, ensure the steel disc is removed from
the connector).
- Use a locking screw to secure the encoder top-mounted unit against pulling
out.
- The locking screw must be lead-sealed for applications requiring mandatory
calibration.
Connection of the encoder
- Use only a screened cable
(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, SCR and SCR Plus interfaces are independent
of the polarity.