5
Explanatory Notes
Scope of supply
NRS 1-40.1 / NRS 1-40.2
1 Control unit NRS 1-40.1 / NRS 1-40.2
1 Terminating resistor 120 Ω
1 Installation manual
System description
The control units NRS 1-40.1 / NRS 1-40.2 have four limiting functions for monitoring the MIN/MAX
water levels (low/high level alarms) and MAX temperature in steam and (pressurised) hot water plants
in accordance with TRD and EN 12952 and EN 12953.
The level electrodes type NRG 1x-40, NRG 1x-41.1 and the temperature transmitter type TRV 5-40
detect the current water level and temperature and their readings are sent as a data telegram to the
CAN bus.
The CANopen protocol is used for the data transfer via CAN bus.
Only one limiting system with one control unit NRS 1-40.1 or 1-40.2 may be used per CAN bus net-
work.
The application of the control unit NRS 1-40.1 or NRS 1-40.2 makes it possible to switch off
different electric circuits, e. g. the safety circuit for the heating system and the control circuit
for the feed pumps or circulation pumps.
