Please read exactly the communication manual page 3 chapter 1.2
1.2 — Registers for ElNet Multimeter
The ElNet Energy & Powermeter is capable of supporting either Function 03 or Function
04 Message Format(See Table 1-3). In a reply to a query from the PC master for a reading from
a particular field, the response from the Powermeter can be either in Format 03 or Format 04 but
will depend on which Format the qeuery was originally sent.
The difference is significant because by using Function 03 the ElNet will only send the
INTEGER part of the field value requested and the PC master will only display the INTEGER
part of the field value.
Function 04 on the other hand, is capable of sending two separate halves of the full FLOAT
requested information (each half contained in a separate register). Then it is the task of the PC
master to merge the two halves into a full FLOAT reply. (For more detailed information See
IEEE Standard 754 Floating-Point).
E.G. 1 If the user’s PC master supports Function 03, then the reply will contain the INTEGER
part of the field only.
The PC master requests the Voltage from Line1, and the actual Voltage in that field is
230.5 Volts.
Function 03 will respond with the INTEGER only i.e. 230V.
E.G. 2 If the user PC master supports Function 04, then the reply will contain the information
stored in the two registers asssigned to that field and will contain the full, accurate reply.
The PC master requests the Voltage from Line1, and the actual Voltage in that field is
230.5 Volts.
Function 04 will respond with a composite reply of both register 1 and 2 giving the full
FLOAT value (in IEEE Format) from that field i.e. 230.5V.