7
Installation
Page 110
gas-lab
Q1
7.2.2.2
EXMFE4 input board
Important note:
The EXMFE4 input board is approved as an
associated
electrical apparatus
of category
ib
according to DIN EN 50020 with intrinsically
safe circuits. This is why sensors and signal transmitters located in hazardous
areas (e.g. zone 1) can be connected to this board. A mixed operation of
intrinsically safe and non-intrinsically safe circuits is not permissible for such an
input board.
One or two intrinsically safe pulse generators in NAMUR technique can be
connected to the first two channels of an explosion-proof EXMFE4 input board,
and the first two channels of the EXMFE4 can be used as message input
channels.
Connect the signals for channels 1 and 2 to terminals
Z1+, Z1-
and
Z2+, Z2-
.
The inputs are intrinsically safe. Use shielded cables for a better interference
suppression. The maximum cable length is 100 m at a cross section of
1.5 square mm. If the cables are longer, you have to ensure that the lines are
installed separately from other conducting lines to avoid interferences.
Moreover, each EXMFE4 board has one intrinsically safe temperature sensor
input in 4-wire technique to be connected to terminals
I+, U+, U-
and
I-
according to the Pt100 Specification.
The board is also equipped with an intrinsically safe input for measuring sensors
(e.g. a pressure sensor) in 4..20 mA-two wire-technique (terminals
P+
and
P-
).
This fourth channel of the EXMFE4 input board can also be used for the parallel
connection of up to 4 measuring sensors with HART interface (multi-drop
procedure). For the sensors, only HART polling addresses from 1 to 4 are
allowed; make sure that the addresses are unambiguous and that the address
assignment corresponds to the assignment in the parameterisation of the
gas-
net
device.