IM-P693-02
EMM Issue 2
3
LCR2251 Level Controller
2.1 Intended use
The LCR2251 level controller is used in combination with the LP20/LP21/PA420 level transmitter as a limit
switch and water level controller, e.g. in steam and water boiler systems, or in condensate and feedwater
tanks. The level controller indicates when a MIN and MAX water level has been reached, and controls a
control valve or pump.
2.2 Function
The LCR2251 level controller processes the level-dependent current signal from the LP20/LP21/ PA420 level
transmitter. This input signal is recognised by the controller as 0 and 100 % of the boiler measuring range,
and shown as an actual value on the 7-segment LED display.
The level controller works with an electro-pneumatically actuated control valve as a continuous controller
with proportional-plus-integral control(PI controller). In the event of deviations from the setpoint, it outputs
a current of 4-20 mA as manipulated variable Y.
Alternatively the controller can be configured to control a pump (on/off control) and transmit a 4 - 20 mA
signal to provide an external level indication (actual value output).
The controller can be configured for fill or discharge control.
If the MIN or MAX water level is reached, after the de-energizing delay the MIN or MAX output contact
switches over in the level controller, and the MIN or MAX LED lights up.
Faults in the level transmitter, the electrical connection or the settings are indicated as error codes on the
7-segment LED display. In the event of a malfunction, the MIN and MAX alarm is triggered.
If faults occur only in the LCR2251 level controller, the MIN and MAX alarm is triggered and the system is
restarted.
Parameters can be changed or the MIN/MAX alarm simulated by operating the push buttons.
2. General product information
Fig. 1
