GESTRA LRG 16-40, Оригинальная инструкция по установке

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LRG 16-40, LRG 16-41 and LRG 17-40
The electrical conductivity is a function of temperature. To relate the measured values to a reference
temperature the resistance thermometer integrated in the electrode measures the fluid temperature.
The electrical conductivity is calculated from the measuring voltages U
U
and U
I
and – through
temperature compensation – is based on a reference temperature of 25°C.
The electrical conductivity is a non-linear function of temperature. For the compensation of the
measured values one of the following three procedures can be applied:
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Temperature compensation Auto: The conductivity electrode records the specific conductivity/
temperature curve of the respective fluid and based on the data obtained, performs the compen-
sation.
The auto-curve temperature compensation is suitable for boilers operating with variable pressure,
which means that the boiler does not have a fixed working pressure (e. g. low load 10 bar, full load
15 bar). The system detects in steps of 10°C all temperatures and conductivity values from 100°C
to the service temperature. For this purpose the boiler must reach its working pressure (with variable
pressure operation: max. allowable working pressure). If the standard curve is not suitable for variable
pressure operation, use can be made of the recorded curve.
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Temperature compensation NORM: The conductivity/temperature curves of 11 normally used
conditioning agents are stored in the electrode and can be selected.
The standard curve temperature compensation is suitable for boilers operating with variable pressure,
which means that the boiler does not have a fixed working pressure (e.g. low load 10 bar, full load
15 bar). The standard curves of feedwater conditioning agents with different basic conductivities com-
pensate for the influence of the temperature on readings within the operating range.
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Temperature compensation LINEAR: A fixed temperature coefficient (Tk) is used to correct the
measured conductivity value linearly.
The coefficient value (default setting: 2.1 % / °C) is normally used for steam boilers operating with
constant pressure. The conductivity is ascertained at an ambient temperature of 25°C. The cell
constant can be modified in order to calibrate the value measured by the electrode. The gradient can
be verified at operating pressure with the aid of a calibrated conductivity meter.
At regular intervals the conductivity electrode LRG 1x-40 sends a data telegram via CAN-bus to the
controller with the following information:
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Measured conductivity value, referred to 25°C as actual value (X),
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Measuring range / adaptation of actual value output,
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Alarm: self-monitoring of electrode supply cables,
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Alarm: temperature sensor defective,
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Alarm: excessively high temperature in terminal box.
A short circuit in the cables leading to the measuring electrode, the measuring tube and the resistance
thermometer or the interruption of the data transmission via CAN bus will be indicated by a malfunc-
tion message.
A sensor monitors the temperature in the terminal box and indicates a malfunction if the limit value is
exceeded.
Explanatory Notes
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Function
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