Technology Center: Level Control
Technical details, instructions and downloads.
All information for perfect installation and configuration.
General Technical Information
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The products of the NR system are virtually unlimited in their application due to galvanic isolation of the power supply. The level controllers are operated in floating mode, meaning the measuring voltage is not connected to any other potential. The evaluation is performed exclusively by measuring the voltage on the medium (liquid) and thus depends directly on the properties of the medium and the electrode spacing.
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Setting the sensitivity The controllers are delivered with a potentiometer set to the midpoint. In most applications, no adjustment is necessary.
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Cable capacity / length The maximum cable capacitance and the resulting cable length are directly related to the sensitivity setting. Longer cable lengths are possible when using low-capacitance cables for the measuring line (NR device to probe). Potential is connected. The evaluation is performed exclusively by measuring the voltage on the medium (liquid) and thus depends directly on the properties of the medium and the electrode spacing.
Basic functions
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NR Min-Max control – 2 switching points (e.g. filling) The supply voltage is applied, and all electrodes are free. The relay is energized, and the switching contact connects terminal 1 to terminal 3. As soon as the level has risen to the maximum electrode (5), a connection to the reference electrode (6) is established via the medium. The relay is de-energized, the switching contact connects terminal 1 to terminal 2, and the device goes into self-hold mode. The relay is only energized again when the level falls below the minimum level (electrodes free).
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RN Max-Min Control – 2 switching points (e.g., empty) The supply voltage is applied, all electrodes are free. The relay is in the rest position, the switching contact connects terminal 1 to terminal 2. When the maximum level is reached (max electrode submerged), a connection to the reference electrode (6) is established via the medium. The relay energizes, and the switching contact connects terminal 1 to terminal 3, and the device goes into self-holding mode. The relay only de-energizes when the level falls below the minimum level (electrodes free).
Functional diagram
The following applies to both versions: 1 point control: If only one level is monitored, terminal 4 (min electrode) remains unused. For double level controllers, connections 1-8 in the lower part of the device are marked as 11-18
A notice!
The desired switching difference results from the length difference between the min and max electrode.
The reference electrode must be at least the length of the minimum electrode. When used in metal containers, the reference electrode can
by connecting terminal 6 directly to the container.
Connections 1 (11) to 3 (13):
Regardless of the supply voltage of the controller, terminal 1 can be supplied with any current type/voltage (AC/DC, max. 250V, 6A).
Terminals 2 (12) and 3 (13) transmit the desired signals.
Find the right one
Basic function selection
ÜL = overflow TL = dry running s = standard – = not available o = optionally available ü = optional (Example level controller: S-NR 01 – filling function or overflow protection)
(Example double level controller: D-NR 98 – filling function and overflow protection
