Kkula
Browse Questions » STEP 7 (TIA Portal): S7 series 1200 over Supervisory control and data acquisition driver S7a - same values in data monitor

About User

Siemens Self Support

Questions Asked: 37.9K

Answers Given: 32

Statistics

Tags

0
  • Open
Siemens Self Support
Asked:18 Oct 2025

STEP 7 (TIA Portal): S7 series 1200 over Supervisory control and data acquisition driver S7a - same values in data monitor

Hello!
I am beginner in PLC world, also in SIEMENS PLCs. I managed communication over private network. Now I have a problem that I get same values on all inputs. Picture below shows my configuration of driver and data monitor. First picture shows when physical input on PLC I0.0 is in state 0. Second picture shows values when physical input on PLC I0.0 is in state 1. Physically on PLC only input I0.0 is forced to 1, input I0.1 stays 0. But data monitor shows both inputs as state 1. Where is problem? Should I use DataBlocks instead of seperate INputs/Outputs/flags in S7A driver? Third picture shows simple PLC program on my PLC. Please help. Thanks in advance! 
For pictures please take a look at attached .zip file.

#sosflex #STEP 7 (TIA Portal) #siemens
1Answers 6Views 0Votes
0 Likes 0 Favourites 0 Followers 0 Comments
Answers(1)
Siemens Test Added an Answer on18 Oct 2025
Siemens Self Support - Input Issue

Addressing Your Siemens PLC Input Issue

Hello! As Siemens Self Support, integrated with SiePortal, I understand you're encountering a problem where all inputs in your data monitor show the same value, regardless of the physical input state.

Possible Causes & Solutions

Based on the information and assuming your network communication is established, the issue likely stems from how the S7A driver is configured to read input data. Here's a breakdown:

  1. Address Configuration: The S7A driver may be configured to read a block of inputs instead of individual inputs (I0.0, I0.1). This can result in all inputs reflecting the state of the first input read.
  2. Data Type Mismatch: Verify the data type configured in the S7A driver matches the actual data type of the inputs in your PLC program.
  3. Cyclic Read Issues: Ensure the cyclic read interval in the S7A driver isn't too long, potentially causing stale data.

Recommendation: Use Data Blocks

Yes, using Data Blocks (DBs) is generally recommended for transferring data between the PLC and external systems. It offers better organization, scalability, and data integrity compared to directly accessing individual inputs/outputs/flags.

Steps to resolve the issue:

  • Create a Data Block in your PLC program.
  • Map your input signals (I0.0, I0.1, etc.) to memory bits within the Data Block.
  • Configure the S7A driver to read data from the Data Block instead of individual inputs.

Further Support

Please refer to the following resources on SiePortal for detailed information:

If the problem persists, please provide the S7A driver configuration details and the PLC program (PTA or STL) for further analysis.

0