S7 300 Redundant (HW and SW configuration)

Hello FAK;

Very interesting videos, thank you.

However, this form of redundancy for the S7-300 CPUs is not supported by Siemens, so we cannot easily help you out with a solution we have no experience in. I suggest you try to contact the promoters of this solution for more information.

Siemens proposes a Fault-Tolerant (redundant) configuration that is considered a hot-swap system; this is the S7-400H system, in which 2 identical S7-400 racks are connected through proprietary fiber-optic cables in such a way that the the I/O statuses and the PLC programs are constantly being updated between the master and standby (reserve) CPUs. Control of the process is transfered to the standby CPU in milliseconds when a fault is detected in the master PLC.

Siemens' solution for redundancy for S7-300 and S7-400 CPUs (outside of the S7-400H CPUs) is called Software Redundancy, and is considered a warm-swap arrangement, because transfer of control between the master and standby CPU can take up to 1 sec, depending on the network used for synchronisation; you can choose MPI, Profibus or Ethernet. Redundancy for the I/Os requires that youn use a Profibus or Profinet connection to the I/Os, where dual IM 153-x (and the I/O modules) are connected through active bus modules that create a backplane bus, allowing switching of the controlling IM 153-x. 

See the following information, that also addresses some of the concerns I have for the system you showed us today:

Software redundancy for S7-300 and S7-400:

https://support.industry.siemens.com/cs/ww/en/view/1137637

Note ET 200M stations must always be set up with active bus modules (6ES7195-7HB00-0XA0 or 6ES7195-7HC00-0XA0), even when the function "removing and inserting I/O modules in Run mode of the CPU" is not possible due to the design principle of S7-300 CPUs.

FAQ collection for Siemens Software Redundancy

https://support.industry.siemens.com/cs/ww/en/view/87604432

Question 17: How to judge if the redundancy system is working normally?

Answer:The soft redundancy system involves redundancy between CPU's and on the DP bus. Observation on the status of "ACT" indicator light of IM153-2 cannot conclude normal operation of the redundancy system. Since switchover between two 153-2's is controlled by the active bus back plane and normal "ACT" status only indicates normal operation of the hardware switchover, not that of the software. Due to that reason the status word of redundancy should also be watched which indicates software switchover status. The redundancy system works normally when both hardware and software switchover are successfully performed.

Hope this helps,

Daniel Chartier

Hello Frsal;

If you plan to work with a Siemens' SWR project, you must start by studying the SWR manual (the first link proposed earlier) to understand the software and hardware requirements. Doing the hardware configuration without taking care of the rest of the program would be nonsense.

Section 7.4 of the manual describes how to setup the hardware configuration for a redundant S7-300. Read it carefully. The following link shows the hardware you can use with the SWR package:

https://support.industry.siemens.com/cs/ww/en/view/15222081

You could also take into account the information provided by our friend H-H in the following link:

https://support.industry.siemens.com/tf/ww/en/posts/need-software-redundancy-sample-project/41746?page=0&pageSize=10

Hope this helps,

Daniel Chartier

Hellop FAK;

If your software skills are zero, you are heading into much trouble to develop your SWR project.

Setting the redundancy network is not really a problem, as discussed in the manual.  If you read the post from H-H proposed earlier, you will see that you will have access to 3 distinct SWR projects on the SWR CD, once you purchase it from Siemens. Each of these sample projects uses a different network (MPI, Profibus, Ethernet) to connect the CPUs in redundancy. You cluld also look at the sample proposed by Anit Kumar in the following thread:

https://support.industry.siemens.com/tf/ww/en/posts/re-s7-300-software-redundancy-switch-over-sequences-not-switch-over-all-output-switch-off/90171?page=0&pageSize=10

I suggest you start by reading the SWR manual attentively, in parallel with sample programs if you have access to them, because SWR is not easy to understand the first time you start one project. Make sure you understand the required FCs and DBs so you can configure the project properly, and develop your own functions.

Hope this helps,

Daniel Chartier