Gestra NRG16-40

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).