5/27/2016 1:19 PM | |
Joined: 4/28/2015 Last visit: 2/7/2024 Posts: 10533 Rating:
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Hello, first thing what had get to my eyes is on MB_COMM_LOAD port address, simply hex 11 is looking strange, I expect another value. Look to PLC HW cfg and check that address of CM1241 module, or click on that PORT area on MB_COMM_LOAD and select right value from list. This is probably problem. I know that you posted that all goes ok with establish of comm_load but can you post Picture of that hw cfg address? |
Last edited by: Duris_I at: 5/27/2016 1:23:08 PMWith best regards... |
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5/30/2016 5:08 AM | |
Joined: 3/28/2010 Last visit: 8/5/2024 Posts: 1051 Rating:
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>Upon establishing the connection successfully, the holding registers show no valves even though the data traffic is active. 1) Most generic Modbus slave simulator programs require you to put some data into the slave registers; they do not self-populate with data. Have you put some known non-zero data into the slave registers? 2) The lack of a blinking Tx LED on the PLC indicates that it is not polling/sending requests. I'm a Modbus guy, not a Siemens guy, so I can't tell from your screen shots; what logic creates a continuing polling action (say, once every second or two seconds) by the Master, so that it is not just a single, one-shot request? |
5/30/2016 8:03 AM | |
Joined: 4/28/2015 Last visit: 2/7/2024 Posts: 10533 Rating:
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Hello Fahad, in case of not light TX but light RX absolutely, pls cross wires Data+, Data-. This is also common problem of not functional communication. |
With best regards... |
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4/1/2017 2:12 AM | |||||||||||||||||||||||||||
Joined: 8/18/2015 Last visit: 4/13/2023 Posts: 5 Rating:
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Hello, Sorry I have the same problem that you had communication with the module CM1241 of siemens, did you manage to solve it? Could you tell me how? Thank you very much good day, greetings |
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4/1/2017 3:38 PM | |
Joined: 4/28/2015 Last visit: 2/7/2024 Posts: 10533 Rating:
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Hello, pls explain your problem clearly. What did you already, what kind of HW, SW? |
With best regards... |
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4/3/2017 5:30 PM | |
Joined: 8/18/2015 Last visit: 4/13/2023 Posts: 5 Rating:
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Hello, Currently my problem is hardware (attached image), the CM 1241 does not blink the LEDs although in the software developed no error is detected. |
5/21/2019 9:10 PM | |
Joined: 11/17/2015 Last visit: 8/13/2024 Posts: 57 Rating:
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There are two unobvious things you should to know, when working with CM 1241 via RS 485 via modbus: 1. Port parameters from HW configuration of CM 1241 have no matter.. because when you call Modbus_Comm_Load - parameters from its instance appling to CM 1241. 2. You have to change mode of communication to RS 485 in the instance DB of Modbus_Comm_Load! Variable MODE in static area should be set to 4. If you will not do that - it will not work at all (no blinking) |
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