12/5/2022 11:48 AM | |
Joined: 11/18/2022 Last visit: 6/20/2023 Posts: 6 Rating: (0) |
Dear all, how does xmt and rcv instruction affect its data buffer again I faced another problem when I try to expand my project. All the ladder of my project is attached. The basic concept of this project is inherited from s7200 system manual page 93-94. It is about sending character from PC and the PLC will send it back. So I planned to control the output of the plc based on the character sent from the PC this way it worked fine. Again I added some conditions such that the PLC will only send the character back if one of its input have logic high. for example if pc send char 'a' the plc will switch on its output Q0.4 and send the char 'a' back to the pc and another condition if pc send char 'c' and if plc input I0.0 is on then it will send back the char 'c' back to the pc but if the plc input I0.0 is off it will not send back the char 'c'. this way it worked fine until the condition which prevent sending back the char met. when this conditions met after that all the logic will not work. this seems for me that xmt instruction affects the data buffer on which it works. any idea please ------------------------------------------------------------------------------------------ Attachmentladder1.pdf (846 Downloads) |
Last edited by: Jen_Moderator at: 12/06/2022 08:27:28New subject after splitting |
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12/5/2022 7:36 PM | |
Joined: 3/9/2018 Last visit: 8/31/2024 Posts: 189 Rating: (14) |
Have a look at project tip52b at What are S7-200 programming tips and where can you procure them? In this example you input ON / OFF on the Serial terminal to put Q0.0 - 0.7 ON / OFF . Also you can see/test in this example there is a timeout and wrong character error messages present. |
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