KROHNE BM 26 A EN - Manual (Page 23)

Installation and Operating Instructions BM 26 A 23
2 Level transducer
2.1 General notes
In addition to the local scale indicator, the BM 26 A can be fitted with a level transducer that
transmits a magnetically-actuated 4 to 20 mA analogue current output for monitoring level outside a
hazardous zone.
This type of indication uses a stainless steel tube containing a resistive reed contact chain that is
clamped adjacent to the measuring tube. The position of the float magnet in the measuring tube
determines the output. This output is calibrated at the factory and does not require any further
adjustment when the BM 26 A is commissioned.
The transducer reading is converted into a current output of 4 to 20 mA by the transmitter that is
potted into the transducer housing. The transmitter module used is detailed in the following sub-
section (detailed technical data is given in section 7.2). The intrinsically safe transmitter may be
used with or without a galvanically-isolated 4 to 20 mA output for the BM 26 A Eex ia version.
BM 26 A Std/ EEx i/EEx d with level transducer (aluminium transmitter housing)
1 Cable entry.
Only Ex i or Ex d-certified
components and cable entry
fittings to be connected!
With M20 x 1.5 thread.
Optional: M25 x 1.5
NPT¾
2 Level transducer housing
3 Stainless steel tube-encased
reed chain
4 BM 26 A measuring tube and
scale with magnetic following
level-indicator
5 PE Ground terminals.
Both terminals must be
connected to Ground!
Dimensions in mm and (inches)