It can be down right confusing setting this up on a Siemens PLC. Hopefully this demystifies the process somewhat! Modbus slave used: www.modbustools.com/modbus_sl... Software: Siemens TIA Portal V16
Thanks a lot brother. Why I am sharing my review is because even the hardware connection error between ports A & B happened to me and rectified it by seeing your video. By following your detailed explanation in hardware and software settings was able to obtain the required result. Thanks once again
Thank you very much for this video. I have managed to connect a Siemens S71212 to a little AB Panelview over RS485 with the help and encouragement it gave me. I did actually manage this using the more recent Modbus blocks. Something that people might overlook is the importance of setting the .MODE parameter of the Load MB block DB correctly. This parameter - hidden away -defaults to zero and must be set to 4 for two-wire half duplex operation as here.
I know im asking randomly but does any of you know a trick to get back into an Instagram account?? I stupidly forgot my login password. I would love any help you can give me.
@Jad Rene thanks for your reply. I found the site thru google and I'm in the hacking process now. Takes quite some time so I will get back to you later with my results.
Realy top-quality instructional video. Will be using the knowledge learned here to start communicating with some ABB inverters for an upcoming project. Many thanks :)
18:40 that's because the MB_MASTER function works by accessing the memory by address with the PEEK/POKE instructions, which can only be done with unoptimized datablocks.
Nice Video, thank you for this! If you don't want to configurate your hardware every time you, also can save your setup in the library and use it per "drag and drop".
I can’t say for sure, but I’ve heard that it’s Siemens that have the A and B/+ and - reversed on the PLC, when compared to most other Modbus devices. Someone else might correct me if I’m wrong.
Hello, I am trying to congigure my PLC as video but "DONE" in first MB_COMM staying at FALSE and not seems values to registers. What may happened? Thank you....
Sorry, I'm a little bit confused! I am going to monitor and control one protection relay by S7-1200 through RS485. I cannot find physical Modbus slave in your program! is it easy to eliminate laptop(as interface) and directly connect modbus slave to S7-1200? How can control 3 slave by this PLC?
Yes, I was just using my laptop here as a simulation slave device. Normally the PLC would be directly connected to the field devices through its CB1241 module. You can definitely control 3 field devices with this. Standard Modbus has an address space of 255. with reserved regions that means you can have up to 247 devices connected.
Hi junt a quick question, I am doing what you say in the video, but there is something weird, even if I don connect a equipment to the serial port still the instrucctions show some activitities for example the comm load intruction shows DONE and the master intruction shows error how this can be?
Do you mean comm load flags done when you dont have a CB1241 attached to the PLC or you don't have the field device connected to the CB1241? Comm load will execute and be fine even if you don't connect anything to the network. it is just establishing itself with the hardware and is slave irrespective.
You rock, thanks for this video. The reverse in wires is a problem from Siemens side or the Slave? Both my slaves had reverse wirings, so I believe the problem is from Siemens side!
Thanks very much! Yeah, since I published this video I've learnt (especially from the comments) that what Siemens classes as "A" and "B" are the reverse of what is general convention in Modbus......... With Siemens, this doesn't surprise me at all!!
Hello, could you please tell me how you added the older version of the MODBUS folder? It would be highly appreciated! (I only have the folder "MODBUS (RTU)")
Sorry! forgot to add it to the description! I'll update it there as well. support.industry.siemens.com/cs/document/109780503/libraries-for-communication-for-simatic-controllers?dti=0&lc=en-SA
Sorry! forgot to add it to the description! I'll update it there as well. support.industry.siemens.com/cs/document/109780503/libraries-for-communication-for-simatic-controllers?dti=0&lc=en-SA
