Flowserve NRS 2-5 - Manual (Page 8)

8
Function
Design
System description
The level switch NRS 2-5 is an analogue electronic amplifier for the capacitance
electrode NRG 211.
In combination with this level electrode it can detect low water level. In addition, the
level switch evaluates possible malfunction signals coming from the electrode and
monitors the electrode supply cable.
The level switch in combination with the level electrode can be used as part of a
low-water level limiting system in steam boilers (separate approval).
The NRS 2-5 has one channel and is provided with a power supply unit and a
voltage decoder. The supply voltage (12 V DC) going to the electrode is converted
into a measuring voltage as a function of the operating mode. The signal decoder
assigns the measuring voltage to an operating mode which is indicated by LEDs at
the front panel of the NRS 2-5.
The level switch is designed for four operating modes:
■ Normal operation
■ Low-level alarm
■ Malfunction in level electrode
■ Malfunction in connecting cable
In the case of a low-level alarm or malfunctions the corresponding output relay will
be de-energized. Optocouplers are connected in parallel and assigned to the
output relays as additional switching elements.
NRS 2-5 c:
19" Slide-in unit with guide rails and 32 pole screw-type connector for installation in
19" magazines to DIN 41494 part 5. Front panel to DIN 41494, part 5, 6 TE
NRS 2-5 d:
Spare 19" slide-in unit, front panel to DIN 41494, part 5, 6 TE
Explanatory Notes
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