How many M-Bus devices can I connect to one single PCD?
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.
PG5 2.0 / M-Bus
Last update: 19.05.2015 07:10
First release: 26.01.2010 13:08