Engineering notes
Meter pulses: when you do not yet need Modbus
One pulse contact and a kWh-per-pulse factor is enough for some files. Do not buy a Modbus meter if the DDC only has a digital input left.
The file says “BMS to read energy”. Someone buys a Modbus meter, then finds the office DDC has no 485 port. The meter sits in the board. Some files only need daily kWh — a pulse input, the DDC counts, times the factor on the label.
Pulses are enough when you need energy, not live per-phase watts. For P, Q, phases, power quality — Modbus and a register map. Write the pulse weight (imp/kWh) on the schedule, on the label, in the DDC. A wrong weight “works” and is still wrong.