This is the first edition of CSA C900.3, Heat meters - Part 3: Data exchange and interfaces, which is an adoption without modification of the identically titled CEN (European Committee for Standardization) Standard EN 1434-3 (first edition, 1997-02).
This European standard applies to heat meters, that is to instruments 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 covered by this standard.
Part 3 specifies the data exchange between a meter and a read-out device (POINT / POINT communication). For these applications using the optical readout head and the CL interface, the EN 61 107 protocol is recommended.
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 meters 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 mains supply is necessary to control the M-Bus. For these applications a protocol according to EN 60870-5 is recommended.