Kkula
Dear friends!
I have a trivial question, but at the moment I really do not know, what is wrong there....
At our customer, there is an AS station, which was supplied from another supplier. I was able to make a classic upload from this station to my PG, to provide quality maintanance work, if needed. In uploaded project, I can see, that theere are some "spare" analogue inputs, and from uploaded HW configuration I can also see, that they are declared as 4-20 mA inputs. This AS is allready connected to our SCADA system (through tcp/ip channel), all works OK.
But now my customer needs some additional measurements in system, and they attached one sensor (4-20 mA) to this spare input on AS. Then they asked me to show this value on SCADA. I said OK, no problem, you do not have to call the original AS station SW supplier (because it is difficult, he must come from another country...), I will simply create a new tag on SCADA and convert the values of IW (of analogue input) to physical value directly on SCADA.
But, (what a surprise), SCADA shows nothing. The shown value is allways 0, no matter, which input current actually flows in this analaogue input... The quality of tag is 80, the output field on scada screen is normal... I do not know, what is wrong.
Any idea???
uel123.
Dear uel123, As Siemens Self Support integrated with SiePortal, I understand you're facing issues reading a newly connected 4-20mA sensor via SCADA, despite a good quality tag (80). Here's a likely cause and solution: **The PLC program likely isn't reading/processing the new input.** Even though the HW config *shows* the input, the PLC logic needs to be configured to read its value and make it available for SCADA via the TCP/IP channel. **Recommendation:** 1. **Check PLC Program:** Verify if the spare analog input is included in any OB (Organization Block) or FB (Function Block) scan cycles within the PLC program. 2. **Data Availability:** Ensure the PLC program moves the raw input value (IW) to a data block (DB) accessible by SCADA. 3. **SCADA Tag Configuration:** Double-check your SCADA tag is correctly linked to the DB address where the PLC places the processed analog value – *not* directly to the IW. You can find detailed information on configuring analog inputs and data transfer in the Siemens Industry Online Support ([https://support.industry.siemens.com](https://support.industry.siemens.com)). Use the search term "PLC analog input SCADA integration".
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