Hello All,

 Am facing strange problem with analog input behavior in my project. Project was commissioned by OEM long ago and was working fine. This particular condition may not come across so far.

S7 400H (6ES7 414-4HM14-0AB0)

IM 153(6ES7 153 2BA02 0AB0)

AI- 6ES7 331 7KF02 0AB0

Main logic is written in OB35. All the input and output are assigned to PIP1(both digital and analog), OB35 is assigned to PIP1 which executes in 100ms interrupt cycle. All the input and output (both digital and analog) are part of process image area and used "IW" addressing for programming. CGP RED IO 52 Library blocks are used for configuring redundancy.

OB35- RED IN - LOGIC - RED OUT- RED DEPASS

OB100, OB80, OB72- RED INIT

OB83, OB85- RED DEPASS

Problem-

Node 8 and 9 are redundant partners with identical card combination. its having DI, DO, AI cards.

Not facing any issue with DI, DO card redundancy behavior.

Analog input card redundancy property is not changed from default. So tolerance=5%, Time discrepancy=0ms, Value applied= lower. Program is done with lower address of AI.

say,

Node 8 AI card=A

Node 9 AI card=B

Test-

1. Remove 1 channel wiring from B

A's reading = actual, B's reading = -32768; result value in logic = A's value-- Good

2. Remove 1 channel wiring from A

B' reading = actual, A's reading = -32768; result value in logic = B's value. ( valid value copied to lower address)--Good

3. Remove Front connector of B

A reading= actual, B reading=32767; result value in logic is A's reading.--Good

4. Remove Front connector of A

B reading= actual, A reading=32767; result value in logic is B's reading( valid value copied to lower address)--Good

5. Power off entire Node8 (A card's node)

All value in A shows 0, all values in B shows actual. Result value in logic shows 0-- Wrong, suppose to get reading of B to A internally by controller. (i think because of discrepancy time exceeded and Value applied setting in project is= lower, A's value not considered)

6. Power off entire Node9 (B card's node)

All value in B shows 0, all values in A shows 0- Wrong (i think because of discrepancy time exceeded and Value applied setting in project is= lower, copied the lower value from B to A)

Am not able to understand why its happening. CPU is not identifying that entire node is in power off condition and value 0 coming from that node is not valid value. I think i missed something in programming part. RED DEPAS was continuously called in OB35, tried by removing that continuous call also, but no improvement. System is in running condition, so am not able to do much R&D in the system.

Attaching plc program, diag buffer taken when node8 is made powered off. Kindly share your suggestions..

Hello Friends,

Any suggestions ?

Hello,

 today i got update from Hotline saying that it is because of - Local Data size is small (CPU property- Memory tab) for priority classes & Priority number for OB81 to 87 are same(interrupt tab in cpu property).

But these are default setting when we created the project. Does anyone come across this kind of issue wrt local data size ?

Dear VIPZ

First sure about RED Configuration. You can use this manual for correct setting:

https://support.industry.siemens.com/cs/ww/en/view/28430682

After new setting delete all chart that is start with @, compile charts and download new configuration and charts.

Regards

sepehr.hsn

Hi,

Thank you for your reply. 

Am using step7, not pcs..will check the manual, could u see any mistake in that attached program ?