Reliablilty & redundancy using PM865 HI controller and SM811 without BC810 module
Suppose there is redundant PM865 HI controller configuration with SM811 connected adjacent to PM865 controller in both primary and redundant controller.
There is no BC810 module between PM865 and SM811.
Is this configuration allowed in a safety system?
What is Reliablilty & availabilty of this type of configuration?
For your question availability of HI controller without BC810: Yes, The availability of the system is still 1:1 & it continues to run even any one controller or any one SM811 or one Sm811 & one controller fails, then still the system works as designed(redunant).
For your question Reliability of HI controller without BC810:Yes, the system still reliable to perform the desired functions on demand & without degradation/failure even in the obsence of the BC810.
If you are not using BC810 at that time your configuration should require TK850 cable with cable length 0.7mtr
Please refer attached manual on page no 97
Function of BC810:
The primary function of BC810 is to divide the CEX-Bus into two physically separate segments for increased system availability, a faulty CEX-Bus unit on one segment will not affect the processor unit or the other CEX-Bus segment. It is also important to note that when using the BC810 together with redundant CEX-Bus units these units shall be mounted on different BC810 CEX-Bus segments.
If you are going with BC810 then each CEX bus should be terminated with TB850 CEX bus termination unit on both the UPPER & LOWER CEX bus ends.