I'm using C #,working on Siemens PLC(S7-200 SMART),it's a total of 8 DO (0,1,2,3,4,5,6,7),I use the function ABWrite(byte: 1,2,4,8,16,32,64,128). However, DO"2,3,4,5,6,7"are worked fine, but DO"0,1"no response. It may be bug?
Best Regards.
Last edit: seamone 2015-12-11
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1-
I don't know S7200 smart PLC, however if it works as S7200+CP243 you cannot access directly to I/O but you must access to the V Area wich is mapped as DB1.
I.E. with Snap7 you read and write DB1 (so use DBWrite) wich contains I/Q/Flags an so on.
2-
In any case, writing the outputs directly from an external device (HMI/OPC/Snap7) has no effect because their values are overwritten by the program logic.
You should write flags then, in your program, you should "OR" them with your conditions..
👍
1
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
I'm using C #,working on Siemens PLC(S7-200 SMART),it's a total of 8 DO (0,1,2,3,4,5,6,7),I use the function ABWrite(byte: 1,2,4,8,16,32,64,128). However, DO"2,3,4,5,6,7"are worked fine, but DO"0,1"no response. It may be bug?
Best Regards.
Last edit: seamone 2015-12-11
1-
I don't know S7200 smart PLC, however if it works as S7200+CP243 you cannot access directly to I/O but you must access to the V Area wich is mapped as DB1.
I.E. with Snap7 you read and write DB1 (so use DBWrite) wich contains I/Q/Flags an so on.
2-
In any case, writing the outputs directly from an external device (HMI/OPC/Snap7) has no effect because their values are overwritten by the program logic.
You should write flags then, in your program, you should "OR" them with your conditions..
Thank you for your reply.
I can directly access IO, the problem is that in my program can control the DO 2,3,4,5,6,7. but can not control 0,1. Let me confused.