Flowserve NRR 2-40 - Manual (Page 8)

8
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,
adopting the CANopen protocol. The transmitted 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 of the level controller is constantly monitored. When 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 (alarm position).
GESTRA’s control terminal and display unit URB 1 enables advanced features such
as adjustable energizing and de-energizing delays of the output relays (1 – 25 s).
Explanatory Notes
Scope of supply
NRR 2-40
1 Level controller type NRR 2-40 (plug-in unit in plastic case with box terminals)
1 Terminating resistor 120
Ω
1 Installation manual
System Description
Use level controller type NRR 2-40 in combination with level electrode type
NRG 26-40 for level control and monitoring. The level controller has the following
functions:
■ Two liquid level limits with one switchpoint each (
HIGH
-
LEVEL
alarm,
LOW
-
LEVEL
alarm)
■ Three-position stepping or modulating control within a predefined proportional
band
■ Continuous level monitoring within the control band defined by two preset limits
The NRR 2-40 features an optional output for a standard signal 4 – 20 mA.
The level data are transferred from the electrode NRG 26-40 to the level controller
via a CAN data bus.