GESTRA NRR 2-40 - Explanatory Notes; Scope of Supply; Description; Function

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System components
NRG 2640
Level electrode NRG 2640, PN 40
Design
NRR 240
Enclosure of insulating material with terminals for installation in control cabinets.
The terminals are externally accessible.
Clipping onto a 35 mm standardized supporting rail (DIN EN 50022).
External dimensions: 73 x 100 x 118
Scope of supply
NRR 240
1 Level controller NRR 240 plugin unit in plastic case with box terminals
1 Terminating resistor 120 Ω
1 Installation & operating manual
Description
The level controller NRR 240 in conjunction with level electrode NRG 2640 is designed for level
control and monitoring. The level controller features the following functions:
n Two level limit values with one switchpoint each (highlevel alarm, lowlevel alarm).
n Threeposition or modulating control within a predefined proportional band.
n Water level is maintained within the defined control band of the electrode.
The NRR 240 features an optional output for a standard signal 4 – 20 mA.
The level data are transferred from the level electrode NRG 2640 to the level controller or an additional
system component via a CAN data bus.
Explanatory Notes
Function
At regular intervals the level electrode NRG 2640 sends a data telegram to the level controller
NRR 240. The data are transferred via a CAN bus to DIN ISO 11898 using the CANopen protocol. The
transmitted measuring data are then evaluated and allocated to the manually adjusted switchpoints.
Optionally a standard signal 4 – 20 mA is established for external level indication. A relay deenergizing
delay can be set manually with the control terminal and display unit URB 1. To guarantee the correct
functioning and safety of the system the data transmitting cycle is constantly monitored by the level
controller. If the CAN bus line is interrupted the level controller sends a visual signal to indicate a
malfunction and the relays 1 and 4 will be instantaneously deenergized. (fail safe position).
GESTRA's control terminal & display units URB enable advanced features such as adjustable energizing
and deenergizing delays of the output relays (1 to 25sec.)