5
Important notes
Usage for the intended purpose
The functional unit consisting of the operating & display unit URB 50 and the level controller NRR 2-52 /
NRR 2-53 in conjunction with level electrodes NRG 2.-.. or level transmitter NRGT 26-1 is used as water
level controller and as limit switch, for instance in steam boilers, (pressurized) hot-water in stallations as
well as condensate and feedwater tanks.
The functional unit consisting of the URB 50 and the level controller NRR 2-5.. is designed for use with
level electrodes NRG 21-.. or NRG 26-21 as well as level transmitter NRGT 26-1.
The
operating & display unit URB 50
and the
level controller NRR 2-52, NRR 2-53
form a functional
unit featuring the following properties:
Level Controller
NRR 2-52
NRR 2-53
Evaluation of the voltage signal of the level electrode NRG 2-.. and standardized
measuring range
X
X
Evaluation of current signal of level transmitter NRGT 26-1
X
X
3-position stepping controller with proportional-plus-integral control action
(PI controller)
and control of an electrically actuated control valve
X
Continuous controller as
PI controller
for the control of an electro-pneumatically
operated control valve
X
Indication of MIN / MAX water level limit
X
X
Current inputs for steam and feedwater flowrate (3-element control) (optional)
X
X
Indication of valve position if control valve is provided with a potentiometer
X
Actual value output 4-20 mA (optional)
X
X
Operating & display unit
URB 50
Indication of actual value (indicated in percent and as bar graph)
X
Indication of valve position (indicated in percent and as bar graph)
X
Standardized measuring range if level electrode NRG 2.-.. is connected
X
Indication/adjustment of control parameters
X
Standardization and evaluation of current inputs for steam and feedwater flowrate (3-element
control) (optional)
X
Trend record
X
Indication and listing of errors, alarms and warnings
X
Test of MIN / MAX output relays
X
Manual/automatic operation
X
Password protection
X
Function
Summary of Contents for NRR 2-52
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