I'm dealing with two PLC-systems. One uses passive backplane bus and another uses active backplane bus. What are definitions of active and passive buses? How are working principles different, both are parallel and use data, control and address lines to communicate, and both have power supplies coupled with bus?

 

Passive backplane - no electronic circuits in the backplane = very high reliability

Active backplane - electronic circuits in the backplane (like a PC motherboard)

Meir

 

A passive backplane consist only of the connection for cards. The removable cards contain all active electronics.

An active backplane has active electronics on the backplane itself. Usually the CPU. A typical PC motherboard is an example of an active backplane.

 

Typically a passive backplane will have no active components, just signals, power, ect.

Active types would have the signals, and bus controllers and such on the backplane.

IF the backplanes are just PCB's, with connectors, filter caps, fuses, and tracres, then they are indeed passive, the actually control signals and data, timing and such is handled by a processor or other devices located on other boards.

If you find that one of the backplanes has bus controllers, actual power supply components, interface devices and such, then it is truly an active backplane.

MJH

 

From what I have been reading on this topic, in the case of a Single Board Computer, an active backplane is for where you need more than the 3 PCI slots provided by the CPU card. So the active part comes from the PCI Bridges provided on the backplane.