Circutor ReadWatt Series Bedienungsanleitung PDF herunterladen (Seite 16)

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Transformation ratio:

The pulses generated by a billing meter are always associated to the secondary, so that the

Conversion Ratio (Transformation Ratio) must be programmed in the case of Medium Voltage

installations for transferring the secondary pulses to the real primary measurement.

Example:

Low Voltage Installation:

Forward voltage: 1/1 -- Transformation ratio = 1.

Medium Voltage Installation:

Transformation ratio = X

In a Medium Voltage installation, where:

Voltage Primary = 27500 V, Voltage Secondary = 110 V.

Current Primary = 200 A, Current Secondary= 5 A.

Transformation ratio = 10000�

4�3�5�- SPECIAL BROADCAST COMMAND

In case the peripheral number assigned to the ReadWatt device is unknown, you have the

broadcast command available (address 00). With this command you can change certain basic

parameters, such as the MODBUS peripheral number or communication speed.

For this you need to know the serial number of the device you wish to access.

The serial number is on the front panel of the unit (Figure 9); this number must be translated

into hexadecimal language so that it can be sent in the broadcast command.

Serie no

( in decimal)

Figure 9: ReadWatt serial no�

It is important to remember that because it is a broadcast frame, there is no conrmation reply.

The broadcast command has the following structure:

Voltage Primary

Voltage Secondary

Current Primary

Current Secondary

ReadWatt

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Circutor ReadWatt Series Bedienungsanleitung Seite 16