How many M-Bus devices can I connect to one single PCD?

FAQ #101364

Principally, there's no limitations set by the driver itself ...

 

... but by increasing the number of devices you will sooner or later reach one of these limits:

  • up to 250 devices can be addressed (with primary addressing)
  • the signal converter supplies power for a limited number of devices (PW6=6, PW20=20, an so on)
  • the number of PCD register is limited. Each M-Bus device will need about 20..30 registers.
  • the Program memory of the PCD is also limited. Each M-Bus device will use about 400..800 lines of code. Add about 5000 lines for the driver itself (each driver).
  • the total reading cycle of all devices will be affected by the number of devices.
    Depending on the type and the speed, you may need up to 1 minute for 10..20 devices already.
  • we also noticed that large M-Bus networks are more often affected by cabling errors and disturbances. 

Therefore, we recommend, to limit the number of devices to 30..50 per network.


The 2 last points can be solved by using more than one serial line, converter and M-Bus driver.

 

Categories

PG5 2.0 / M-Bus

Last update: 19.05.2015 07:10

First release: 26.01.2010 13:08

Views: 4633

The requested software / document is no longer marketed by Saia-Burgess Controls AG and without technical support. It is an older software version which can be operated only on certain now no longer commercially available products.

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