Description
The level electrodes NRG 1...-40 work according to the
conductivity measurement principle and detect the min. level
in electrically conductive liquids:
? One level alarm with one switchpoint
Use level electrode NRG 1...-40 in combination with level
switch NRS 1-40 or NRS 1-40.1 and/or other system components. The NRG 1...-40 in conjunction with its associated control equipment constitutes a water level limiter with
periodic self-testing routine (SMART function) in accordance
with TRD 604, sheet 1 and 2 and EN regulations. The level
data are transferred from the electrode NRG 1...-40 to the
control unit via a CAN bus using the CANopen protocol.Function
The electrode operation is based on the conductive measuring
principle using the electrical conductivity for signalling liquid
levels. Some liquids are conductive, which means that they
allow an electric currrent to flow through them. For the safe
functioning of this device a minimum conductivity of the liquid
to be monitored is required.
The conductivity measurement method can detect two
conditions: electrode rod submerged or exposed, meaning
switchpoint reached (or exceeded) or not yet reached. Before
installation, the electrode rod must be cut to length to give the
required low-level alarm and effect the consequent cut-out
of the burner circuit.
The system incorporates an additional electrode that provides automatic monitoring of the electrical resistance path
between the measuring electrode and the earth. When the
measured value falls below the admissible resistance value
the burner shutdown is endorsed by interruption of the burner
protection circuit.
At regular intervals, the level electrode NRG 1...-40 sends a
data telegram to the controller NRS 1-40. The data transfer
is effected by means of a CAN bus according to DIN ISO
11898 adopting the CANopen protocol. One controller type
NRS 1-40 can be used for two level electrodes NRG 1...-40
(low-level limiter arrangemant).