Hi All,
I have a small system consisting of sensors, buttons and LEDs all connected to a simulated Siemens S7-1200. The PLC runs a program that monitors and the various input pins, runs some logic and generates an outputs written to the Output pins. The system in Siemens works as expected – I’m able to place TIA Portal in online mode, control the various states from the Simulated PLC in SimPLC and watch as they affect the state of tags in the portal. I’m also able to monitor the various PLC pins in Ignition and adjust my graphics accordingly but my problem is writing back to the PLC or changing the states of the input pins on the PLC from Ignition. In other words, I’d like to, for instance, press a button in Ignition and have the value on the PLC change from true to false but the change only seems to happen locally in Ignition, not on the PLC itself. Even when I toggle the pin in the Designer I can see the changes locally in Ignition but not in Siemens. I’ve set the “Optimistic Writes” on the tag’s Tag group to true and the “Read Only” property of the tag to false but none of these seem to work. I’m sure there’s a way of controlling a Siemens PLC pins from SCADA, what am I missing? FYI: I am using Ignition 8.3.3 and the Enhanced Siemens Driver module.
Are they set as writable from HMI in the PLC?
Are you trying to write the value from the tag browser in the designer. is that is working then it means that the issue is between the visualization and the tag in ignition. If not then the problem is between the ignition gateway and plc.
Regards
Hi Andrew, thanks for replying. Yes I made sure to set the tags to “Writable from HMI“
Hi Arnaud, thanks. Yes, I’m able to write to the PLC tag in the tag browser and the value does change in Ignition but not in the Simulated PLC or in the Portal so it definitely does seem that the issue is between my gateway and the PLC. Any thoughts on how this could be addressed?
This might be relevant? S7 1500 Tags Writing Issue - #17 by Kevin.Herron
I don't remember what I found out when I looked into giving an error or something for this issue. If you share more details, I can take a closer look sometime.
Debug logs, wireshark, TIA project, repro steps, etc. You can upload here:
Edit: To be clear, it is expected not to be able to write to inputs. The "issue" is that the driver doesn't give an indication of this. I'm not sure if it can or not. It's possible the PLC "accepts" the write and does not provide an error.
Even in simulation PLC, input can’t and shouldn’t never be overwrite by anything. I would recommend to use a DB an link ignition tag to that DB.
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