Example of Modbus TCP Master

[Mr Lam]

Hi there,

I recently downloaded OpenAPC for Windows x86 (my laptop's OS is Windows 7
Professional, 32bit) and I am getting familiar with Control Room's
functions. I have been trying to get status of digital inputs and value of
holding registers from a Siemens's PLC, which I programmed to work as a
Modbus Server, and display the result to Control Room. But I could not
succeed. I have been using some Modbus tool to check the performance of PLC
and it is still working correctly (inputs and register of PLC give correct
results to Modbus tool).
So I would like to get help from experts of OpenAPC. Particularly I would
like to have a simple example which can read status of Digital Input
Register 1 and content of Holding Regster 40001 to Holding Register 40003.

Thanks in advance

Regards

[Mr Lam]

Hi,
I have been doing as your instructions but get no success. Please see the
my attached project. In this project I have tested with both Unit ID of 0
and 1 but all LC_Numeric_Display fields still display results of 0 (it
should display results greater than 0 as I viewed with other Modbus Tool).
Can you suggest some other hints on this matter ?
I am looking forwards to your assistance.
Thanks.


On Mon, Jan 13, 2014 at 1:37 PM, <qxc(a)gmx.de&gt; wrote:

>  Hi,
>
>  please find attached a screenshot of the configuration that should fit to
>  your problem. Regarding the IO base address offset I'm not quite sure, may
>  be values have to be +-1 since I'm not sure if your PLC/the MOBUS plug-in
>  starts counting at address 0 or 1
>
>
>   *Gesendet:* Samstag, 11. Januar 2014 um 12:35 Uhr
>  *Von:* "Mr Lam" <lamtranhn(a)gmail.com&gt;
>  *An:* openapc(a)lists.fedorahosted.org
>  *Betreff:* Example of Modbus TCP Master
>   Hi there,
>
>  I recently downloaded OpenAPC for Windows x86 (my laptop's OS is Windows 7
>  Professional, 32bit) and I am getting familiar with Control Room's
>  functions. I have been trying to get status of digital inputs and value of
>  holding registers from a Siemens's PLC, which I programmed to work as a
>  Modbus Server, and display the result to Control Room. But I could not
>  succeed. I have been using some Modbus tool to check the performance of PLC
>  and it is still working correctly (inputs and register of PLC give correct
>  results to Modbus tool).
>  So I would like to get help from experts of OpenAPC. Particularly I would
>  like to have a simple example which can read status of Digital Input
>  Register 1 and content of Holding Regster 40001 to Holding Register 40003.
>
>  Thanks in advance
>
>  Regards
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>
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-- 
--------------------------------------------------
*Mr*. Trần Hồng Lam

Mobile: [phone]