Handbuch-KnxSmartmeter-85A-en-3.odt, 2018-10-04
Seite 9 von 69
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The line should be laid at a distance of at least 10cm to high-frequency sources of
interference. These include for example:
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Inverter, converter
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WLAN Router
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Counter with GSM interface
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Equipment of a radio - bus, as Enocean, KNX-RF ...
For the highest precision the lines to the current sensors can also be cut to the minimum
required length. When shortening it is to make sure that also the drain wire is connected to the
shield terminal. In addition, care must be taken that after shortening, the cable shield is again
insulated by a shrinking tube, as it was the case in the original condition. As an alternative to this
insulation the electrical safety can also be ensured by maintaining a safety distance between the
non - insulated part of the shield and all the live conductors by at least 10mm.
If necessary, it is also possible to extend the lines for the current sensors up to 10m. However,
an increasing cable length is accompanied by a higher disturbance in the measurement signal.
Thus, the measurement accuracy for small currents is reduced. It is therefore recommended not
to extend the line, if currents below 500mA (about 100W) shall be accurately measured. To
affect the measurement accuracy as little as possible in a case of an extension the following is
recommended:
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Only use shielded lines with at least 0.5mm² . The shield of the extension must be
connected to the shield wire (drain wire) of the existing measurement line.
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The extension should be soldered to the existing measurement line.
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The shield of the extension or the extension drain wire must be connected to the
Smartmeter at the shield terminal.
For safety reasons the extension has to be attached so that from the shield and the wires of the
extension to all live parts in the vicinity of the extension a double or reinforced insulation is
maintained. This can be achieved by insulation and/or the observance of minimum distances.
Commissioning
After connecting all the cables according to the connection diagram 1 the device is ready for
operation. Once the KNX bus is connected, the “POWER” LED lights up permanently green after
a short start-up (about 3 seconds). From that time the device performs measurements
continuously.
By a short light up the channel LEDs E1, E2 and E3 signalize measuring an energy amount of
1/1000 kWh in the particular channel. When the Smartmeter record data onto the SD card, the
POWER LED lights up red during the writing process. To prevent data loss on the SD card the
SD card may not be drawn during this writing phase. SD card is inserted in a way, that the
contacts of the SD card are on the top.
Enertex
®
Bayern GmbH – Ebermannstädter Straße 8 - 91301 Forchheim - Deutschland - [email protected]