I have minimal details of hardware configuration of the 6ES7417-4HT14-0AB0 used in a redundant setup, but apparently the spare CPU (not part of the installed CPU's) is of the older firmware version V4.5.2

One of the installed "417-4HT14 CPU's needs to be changed" as it is suspected of causing the vessel management to black out. 

I would just like to confirm if the older firmware can be used? I presume if newer firmware functionality is used in code sections, then the older firmware will not be able to run and the need to downgrade program sections using any new firmware functionality.

Just to clarify, I've not being present at the Control System onboard a vessel offshore. One of my oil & gas contacts shared the Control system Diagnostic files with me to assess and advise if I could assist in diagnosing and identifying the reason this vessel offshore experienced a blackout, total power failure.

Thanks Daniel Chartier,

I have found the “Download Operating System Updates V4.5H CPU412-3H / CPU414-4H / CPU414-4H PG / CPU417-4H ” and will follow the procedure for upgrading firmware from 5.2 to 5.6 step by step.. not able to do from 5.2 to 5.6 I understand. 

https://support.industry.siemens.com/cs/de/en/view/109474703

I have received two file for the Diagnostic buffer of module CPU 417-4 H for both Rack 0 and Rack1 in txt format. Will go to Classic forum to attach for review and advice. I am listing the errors that have occurred since the 11th August 2025 to 16th August 2025 for now to gain a better understanding of what the sequence of event are. 

The history of issues however started way back in 2023.. lol

I have noted the PGS_B.txt file date is all from 1994. I am suspecting Memory Card failure, as well as the Fibre links. Waiting for pictures of the Rack0 and Rack1 for LED statusses

Thanks Daniel, waiting on client, job on hold, think they plan on testing SIPROTECH Protection relays for power generation units as there is locally equipment available to do this and verified in order. Spares of Flash memory for S7400H CPU and OLM's need to be organized onsite.

1. I investigated loss of connection to Profibus slaves for your comment, 

 "Next, your diagnostic buffer shows a large amount of OB122 errors  in FC 1070 and higher. This often happens when you lose connection to a Profibus slave or Profinet IO            Device and attempt to read or write values while they are not accessible."

I have only assessed events that occurred on the 11th August 2025 concerning Profibus slave communication “failure” and “return” these are listed sequentially below as taken from the PGS_A.txt file provided. 

From the event 2175 through event 2152 there are fourteen events listing the “Distributed I/Os station Failure”. 

Profibus slave nodes 11, 12, 13, 14, 15, 16 , 17, 4, 5, 6, 7, 8, 9 & 10.

Event 2175 of 3000: Event ID 16# 39C4
Distributed I/Os: station Failure
Address of the affected DP slave: station number:
11
DP master system ID:
1
Log. base address of the DP slave: Input address: 16352
Log. base address of the DP master: 16383
Requested OB: Rack failure OB (OB86)
Priority class: 25
External error, Incoming event
10:09:01.098 PM 08/11/2025
(Coding: 16# 39C4 1956 C054 3FFF 3FE0 010B)

Event 2174 of 3000: Event ID 16# 39C4
Distributed I/Os: station Failure
Address of the affected DP slave: station number:
12
DP master system ID:
1
Log. base address of the DP slave: Input address: 16349
Log. base address of the DP master: 16383
Requested OB: Rack failure OB (OB86)
Priority class: 25
External error, Incoming event
10:09:01.101 PM 08/11/2025
(Coding: 16# 39C4 1956 C054 3FFF 3FDD 010C)

Event 2173 of 3000: Event ID 16# 39C4
Distributed I/Os: station Failure
Address of the affected DP slave: station number:
13
DP master system ID:
1
Log. base address of the DP slave: Input address: 16348
Log. base address of the DP master: 16383
Requested OB: Rack failure OB (OB86)
Priority class: 25
External error, Incoming event
10:09:01.101 PM 08/11/2025
(Coding: 16# 39C4 1956 C054 3FFF 3FDC 010D) ..... The rest can be found in the PGS_A.txt file.

From event 1368 through event 1025 there are fourteen events listing the “Distributed I/Os station return”. Profibus slave nodes 13, 14, 15, 16, 17, 4 , 5, 6, 7, 8, 9, 10, 11 & 12.

2. What I noticed is that the fourteen events listing the “Distributed I/Os station Failure” follow event 2176, “A master has gone into STOP mode because its partner CPU is also a master (link-up error). This is the specific event that has caught my attention and so would like to focus on the first fifteen events 2176 to 2190 that occurred on the 11th August 2025. and in particular event 2176.

When following the events 2178 to 2176 below, I understand that the loss of redundancy, due to Standby CPU failure of the affected CPU in Rack 1, is the initial step, leading to the Stop of event 2176.

Event 2178 of 3000:  Event ID 16# 7301
Loss of redundancy (2oo2) due to CPU failure
CPU affected: Standby CPU in rack 1
Requested OB: CPU redundancy error OB (OB72)
Priority class: 28
Incoming event
10:08:59.297 PM  08/11/2025
(Coding: 16# 7301  1C48  005B  F100  0000  0000)

Event 2177 has the Master CPU in Rack 0 change from redundant mode to solo mode and is in Run operating mode already, being the Master CPU of the pair of CPU's.

Event 2177 of 3000:  Event ID 16# 43E3
Master CPU: Change from redundant mode to solo mode
Previous operating mode: RUN (redundant mode)
Requested operating mode: RUN
Event occurred in the master CPU in rack 0
Incoming event
10:08:59.297 PM  08/11/2025
(Coding: 16# 43E3  F898  0000  0000  0000  0000)

Event 2176 is the strange situation where the Master CPU of Rack 0 in Run mode goes into Stop mode because it's partner CPU of Rack 1 "is also a Master... (link-up error).

Surely if event 2178 has the "Standby" CPU failure of Rack 1 at 10:08:59.297 PM  08/11/2025, it can't suddenly become a master at 10:08:59.775 PM  08/11/2025, 478ms later...

Event 2176 of 3000:  Event ID 16# 43D4
A master has gone into STOP mode because its partner CPU is also a master (link-up error)
STOP of: unknown (Z1: 0000)
Valid master is: unknown (Z2: 0000)
Previous operating mode: RUN
Requested operating mode: STOP (internal)
Event occurred in the standby CPU in rack 1

3. Also noted below, a Standby CPU submodule error in Rack1.

Event 2188 of 3000:  Event ID 16# 45E4
Standby CPU: Change from redundant mode to error-search mode 
Event: SYNC submodule error 
Previous operating mode: RUN (redundant mode)
Requested operating mode: Error-search mode
Event occurred in the standby CPU in rack 1
Internal error, Incoming event
10:02:53.476 PM  08/11/2025
(Coding: 16# 45E4  F19E  C300  0000  7955  FFFF)

Just to clarify, I've not being present at the Control System onboard a vessel offshore. One of my oil & gas contacts shared the Control system Diagnostic files with me to assess and advise if I could assist in diagnosing and identifying the reason this vessel offshore experienced a blackout, total power failure.