I have meet very unusual issues with analog input modules (6ES7 331-7NF10-0AB0):

2 channels jumped to 25%, when a real value from field device was 0%, and card stucked in this state till turn off. After turning on all meassures become in normal state.

Another case: 6 channels simultaneously alarmed "wire break". This module wasn't connect to any measurement device, and all point were connected to 10K resistors. Trying to simulate real wire break by disconnecting resistor from any point didn't resulted to any changes. After reset all points become to normal.

Both cases happend in different parts of the site and in different time.

What can be reason for such issues?

Hello edr

We performed any believable and unbelievable checks. All looks OK. Grounding and noises are also OK. But problem countinue to appear. Last time we had same AI(6ES7331-7NF10-0AB0) module, simultaneously alarmed CH02-CH07 wire break. In diagnostic buffer of the specific card are next messages:

"External error

Faulty Module

There is a channel error."

Voltage on input is 24.5V

Current 4.8 mA

Inputs are shorted with resistors of 5.0 kOhms.

Any ideas?

We have a customer who is having the exact same problem, all 8 readings on the module freezes and the sf light goes on.

It happened 3 times in the last few months. They have some spare parts and assumed that the module was faulty and replaced it. But today I was there when it happened and I noticed that simply switching on/off made the module work again.

I tried all 3 other modules previously replaced in the last months and they all worked.

Modules are 6ES7-331-7PF00-0AB0 with PT100 reading. System was installed approximately in 2004 and this never happened before recently.

Right now I have a test rig with 4 of those that were removed and supposedly defect, there is nothing connected except for power, maybe this is the reason why I have the same diagnostic (I dont have any resistors or PT100 connected):

External error
Faulty Module
There is a channel error

Any ideas? I will program something to avoid damage to material in the process in case those readings stalls again, but I would like to know the cause to this as well.

I have read entry 6568425 and also 5296808 about a defective component that could cause "inconsistent values" but it says it is solved from version 6 and mine appear to all be version 7.

Thanks and best regards,

Frederik

Dear Ferderik,

Let's cooperate on reosolving this problem, and try to find the reason for such kind of problems. When I applyed to local resepresentive of Siemens i didn't received any objective answer. We performed very wide checks of power supply system on site like harmonics checks, spike checks, and of course voltage and current. And we didh't saw nothing unusual.

I think that the problem can be in firmware, on our site we have following configuration:

Redundand CPU 417-4 H, 2 redundant loops of remote IO panels ET-200M in total aproximately 70 panels, all panels have the same configuration (16DI:16DI;16DO:16DO;32DO;32DO;8AI;8AI), following are firmware versions:

CPU 417-4 H     6ES7 417-4HL04-0AB0     firmware:V 4.0.8

IM153-2            6ES7 153-2BA01-0XB0      firmware:V 4.0.7

CP 443-5 Ext    6GK7 443-5DX04-0XE0      firmware:V 6.1.7

AI8x16Bit         6ES7 331-7NF10-0AB0      E-Stand 5

Which HW configuration and versions of firmwares you have on your customer's site?