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I need your help to solve a "strange" problem I am facing.
My wago 750-842 does not write digital outputs and does not read digital inputs.
Below you can find my very simple program, along with the harware configuration.
To summarize, I have a 8 channel DO module, a 8 channel DI module and a 2 channel AI module.
I am using Codesys 2.3.9.62. 750-842 is not compatible with Codesys v3 as far as I know.
I correctly receive the 2 AI, but my DI in the program are always false, regardless of the real DI state.
DO are also always false, even if I activate the output from program.
I feel like I am missing some very easy configuration step or something like that.
I also wanto to point out that:

  • hardware is working correctly as all I/O respond to modbus request as expected
  • program is correct as everything works as expected in simulation mode

Can you please give me suggestion on how to properly read inputs and write outputs so that hardware behaves like it is expected? 

K-BUS
|____ 750-530 (channels from AT %QX0.0 to %QX0.7)
|____ 750-430 (channels from AT %IX2.0 to %IX2.7)
|____ 750-461 (channels AT %IW0 and %IW1)

Program (ST):

VAR
   i_ch_1 AT %IX2.0 : BOOL;
   i_pt100_1 AT %IW0 : INT;
   o_ch_1 AT %QX0.0 : BOOL;
   o_ch_2 AT %QX0.1 : BOOL;
END_VAR

o_ch_1 := i_ch_1; (*DO 1 on if DI 1 on, off otherwise*)
o_ch_2 := i_pt100_1 > 100; (*DO 2 on if temperature > 20°, off otherwise*)

Link to download the project
electrical wiring 1
electrical wiring 2

andreapier
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  • first, do you forget to run your PLC after upload? Also, I see `%IX0.0` and `%IW0` is the same tits and cannot be different inputs. – Sergey Romanov Feb 26 '20 at 05:11
  • No i did not forget to run the program after uploading it (online -> Login, then Online -> Run). Those addresses are assigned by Codesys so I can't really change that. But you were right, I made a copy-paste error in the input addresses. See my edited question. – andreapier Feb 26 '20 at 12:09
  • Do you have a power supply to modules and end-module? – Sergey Romanov Feb 26 '20 at 14:05
  • Yes I do. I have a 750-602 power supply before any module and a 750-600 at the end. I will attach a picture when I get home later today – andreapier Feb 26 '20 at 15:53
  • Can you sare your project, please. – Sergey Romanov Feb 27 '20 at 04:32
  • Here you are. Thanks for taking the time to help me, I really appreciate that. – andreapier Feb 27 '20 at 08:17
  • I've checked it today. Everything looks fine and simulation did work for me, Unfortunately, I do not have this model to check online. Anyway, it looks ok. Does the simulation work? – Sergey Romanov Mar 01 '20 at 05:56
  • Yes it does. I attached 2 pictures so you can have a look at the electrical wiring and module connections. Can you check it out please? – andreapier Mar 01 '20 at 09:13
  • The order and number of modules in the project file do not match for me. You should have modules in exactly the same order in K-Bus as they physically attached. – Sergey Romanov Mar 03 '20 at 05:30

0 Answers0