Author Topic: ModbusTCP Component valid addressing  (Read 1099 times)

scott.clark

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ModbusTCP Component valid addressing
« on: December 04, 2020, 01:05:58 PM »
I have a torque controller I would like to read and write to by ModbusTCP.

The registers I should be able to read from are in the range of:

308455 thru 308502 (unsigned integer data type)

I setup a BasicLabel component with ModbusTCPCom1 component and PLCAddressValue = 308455.  But all that is returned on this or any of the other registers is 0.

Is this  308455 thru 308502 a valid address range for the ModbusTCP Com component?

I know I have communications.   if I disconnect the ethernet cable, it repsonds with "No values returned from Driver"  and a "Could not connect ...." message.




bachphi

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Re: ModbusTCP Component valid addressing
« Reply #1 on: December 04, 2020, 06:59:43 PM »
What is the brand/model of the torque controller?

Any link or manual to the page where you decoded the given addresses?
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Godra

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Re: ModbusTCP Component valid addressing
« Reply #2 on: December 04, 2020, 11:05:04 PM »
Unsigned 16-bit integer would be addressed as U308455 or 308455@U while 32-bit would also have "L" next to "U".
An offset of +1 might also be required for the address (308456 instead of 308455).

There is also another Modbus master app available for quick testing:

   https://www.advancedhmi.com/forum/index.php?topic=2567.0
 

bachphi

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Re: ModbusTCP Component valid addressing
« Reply #3 on: December 09, 2020, 10:29:04 AM »
so he did not bother to response!
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scott.clark

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Re: ModbusTCP Component valid addressing
« Reply #4 on: December 16, 2020, 02:39:46 PM »
Sorry for the slow response.  I didn't want to respond until I had time to go through all the suggestions that were provided.

The torque controller was an Estic Handy 2000 touch unit. 

The Modbus Master utility Godra provided was an awesome tool to use in resolving the communications. 

What I found was that Estic has a requirement to send a watchdog packet within every 5 seconds.

"Write the value 0xFFFF to Holding Register 0x1000(Watch Dog) in every constant seconds (within 5 sec).
Handy2000 controller is watching values that are stored in this address, and if there is no writing data within
5 sec, the controller will judge the communication with the touch panel is Not-Connected. The controller will
remove input data from the touch panel, and input data will be invalid after the judgement."

So, essentially, it was throwing away my requests and not giving me back any error.

Another issue was that I had to subtract "1" from all the addresses that were published in the programming guide. I have seen this issue before, not sure why this is common.

Thanks for the support.