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MODBUS TCI/IP RK512

Thread Starter: alibi   Started: 5/30/2012 4:26 PM   Replies: 13

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  5/30/2012, 4:26 PM
alibi
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Hi to everyone,
Now I am facing the problem of sending and recieving data. Do I need to create new data block for the registers or what?
I am very new to this, but somehow I managed to make a program and configure it. The problem is in sending and fetching.

And second question, if I need to connect several non-similar devices to one master, what I should do?

Please reply ASAP and thank you in advance,
alibi
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  5/30/2012, 4:39 PM
Kaulquappe
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Hello Alibi,
what would you really like to do? Communicate via RK512 - this is a serial point-to-point protocol, or communication via ModbusTCP - this is an ethernet protocol? Which devices are you intending to connect to which system?

Regards,
Kaulquappe




=== Edited by Kaulquappe @ 5/30/2012 4:40 PM [GMT ] ===
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  5/30/2012, 4:43 PM
alibi
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Actually I use RK512 protocol, but my station is connected via Ethernet. I don't know how it is possible, but Is it right?
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  5/30/2012, 4:59 PM
Kaulquappe
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Hello Alibi,
unfortunately I'm not a clairvoyant, just a technician. But I know for sure that you can't use RK512 via Ethernet.
So again: which system do you use, which modules, which device is connected?

Regards,
Kaulquappe
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  5/30/2012, 5:09 PM
alibi
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Hello Kaulquappe,
This is my HW Config: 
1. CPU 314C-2 DP 6ES7 314-6CF02-0ABO
2. CP 343-1 Lean
3. CP 341-RS422/485

I use MODBUS TCP protocol.
Best,
Alibi
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  5/30/2012, 5:17 PM
Kaulquappe
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Hallo Alibi,
which blocks do you use for ModbusTCP communication, the library Open ModbusTCP via NCM CP or blocks which you programmed on your own?
CP343-1 is able to talk TCP/IP. When you'd like to use ModbusTCP some additional programming is necessary.

Regards,
Kaulquappe
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  5/30/2012, 5:32 PM
alibi
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Hello Kaulquappe,
I made a mistake. Not TCP, I used libraries from CP PtP. Sorry for that.
Best,
Alibi
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  5/30/2012, 5:55 PM
Kaulquappe
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So Alibi you are using Modbus RTU. Does the CP341 act as master or slave? Which and how many devices do you want to connect? One and only one connected device is the master and the first and most important thing is to know which one acts as master.

Regards,
Kaulquappe
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  5/30/2012, 9:01 PM
alibi
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Ok. CP 341 acts like a master. I want to connect several non similar multimeters, powermeters and fetch this data on HMI.
Thank you for your help and patience,
Alibi
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  5/30/2012, 10:57 PM
dchartier
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Hello alibi;
You need to answer these questions before we can help you further:
These “several non similar multimeters, powermeters” , are they already Modbus RTU slaves, or can you add a comm. module to them to make them Modbus RTU slaves?
Note that it would be a lot easier if you gave us the make and model of these as yet unnamed equipment.
Second, do they all support RS-485 as a physical layer? Notice that you need a CP 341 woith RS-485 interface to control a multislave Modbus netwrok:
6ES7341-1CH02-0AE0
Third, do they all support the same comm. parameters (data speed, number of bits, number of start bits, number of stop bits). This is important, since one master can only exchange with slaves that commit to the same bus parameters.
Hope this helps,
Daniel Chartier
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