ÖNORM EN 1434-3

This European standard applies to heat meters, that is to instnirnents intended for measuring the heat which, in a heat-exchange circuit, is absorbed or given up by a liquid called the energy-conveying liquid. The meter indicates heat in legal units. Electrical safety requirements are not cavered by this standard. Part 3 specifies the data exchange between a meter and a read-out device (POINT / POINT comrnunication). For these applications using the optical readout head and the CL interface, the EN 61 107 protocol is recornmended. Further stipulations are set out for the data communication between several meters and one master unit in a local network (MULTI-POINT communication). This can be done with a few rneten with a hand held master unit by using the inductive interface on the Meter-Bus (in the following called the M-Bus). For bigger networks with up to 250 meters, a master unit with AC rnains supply is necessary to control the M-Bus. For these applications a protocol according to EN 60870-5 is recommended.