GESTRA NRR 2-50, NRR 2-51

The level controller NRR 2-50, NRR 2-51 uses the level- dependent voltage signal emitted by the level electrodes NRG 2.  or the level-dependent current signal emitted by

the level transmitters NRGT 26-.. These input signals are standardized by the controller to 0 and 100 % of the boiler measuring range and indicated as actual value by the seven- segment LED display.

Level controller NRR 2-50: The level controller works in conjunction with an electrically actuated control valve as three-position stepping controller with proportional-plus- integral control action (PI controller). In the event of a deviation from the setpoint, the electrical actuator is controlled by two output contacts and two flashing LEDs indicate whether the control valve opens or closes.

The controller can be configured for fill or discharge control.

An additional output contact indicates when the MIN or MAX water level is reached (the desired function is switch- selectable). After the de-energizing delay has elapsed, the output contact switches over and the LED for MIN or MAX is illuminated.

Level controller NRR 2-51: The level controller works in conjunction with an electro-pneumatically actuated control valve as continuous controller with proportional-plus-integral control action (PI controller) and, in the event of a deviation from the setpoint, outputs a current of 4-20 mA as mani- pulated variable Y.

The controller can be configured for fill or discharge control.

When the MIN or MAX water level is reached, the MIN or MAX output contact is switched over in the level controller after the de-energizing delay and the MIN or MAX LED is illuminated .

Level controller NRR 2-50, NRR 2-51: Any faults or malfunc- tions in the level electrode, the level transmitter, the electrical connection or the settings will be indicated as error code by the seven-segment LED display. In the event of a malfunction a MIN and MAX alarm will be triggered.

If errors occur only in the level controller NRR 2-50 / NRR 2-51, a MIN and MAX alarm is raised and the system is restarted.

Parameter settings can be changed or a MIN/MAX alarm be simulated by operating the rotary button.

The level controller NRR 2-50 features an actual value output 4 – 20 mA for external level indication.

The parameter settings can be secured with the help of a password to prevent unauthorised users from access and editing. The default password cannot be changed.