CODESYS - the IEC 61131-3 automation software

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PostPosted: Mon Apr 01, 2019 6:15 am 
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Hi.
As we know, there is some limits for Modbus TCP Slave quantity under Modbus TCP Master - 32 devices (64 since SP13).
I have many devices and as workaround I use many Modbus TCP Masters with 32 devices in each of them.
Seems like it works but I want to understand it this correct solution or potentially dangerous?

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PostPosted: Mon Apr 01, 2019 10:35 am 
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As modbus TCP relies on TCP, the only limit I see is from IP addressing/subnets.
Standard modbus applies only if your communication is in between modbus RTU/TCP gateways (so you need the use of the slave identifier, which is 0-254).


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PostPosted: Mon Apr 01, 2019 12:05 pm 
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Thanks. Honestly it's obvious.
If there were no restriction (or 247 as upper limit) for slaves in Modbus TCP Master - I would have no questions.
But my question not about specification Modbus TCP or TCP, I just wonder is this correct to use many Modbus TCP Master under same Ethernet Adapter node.
Maybe it's unexpected-from-user solution and it will create problems for IO-drivers or something other...
So I just want to get some advice from developers.

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PostPosted: Wed Jan 22, 2020 3:53 pm 
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e.kislov wrote:
Thanks. Honestly it's obvious.
If there were no restriction (or 247 as upper limit) for slaves in Modbus TCP Master - I would have no questions.
But my question not about specification Modbus TCP or TCP, I just wonder is this correct to use many Modbus TCP Master under same Ethernet Adapter node.
Maybe it's unexpected-from-user solution and it will create problems for IO-drivers or something other...
So I just want to get some advice from developers.

Whooa,no response from Dev?
I have a simmilar newbie question…..
How many slaves/channels can be assigned to a Codesys device ?
(Docs and googling did not reveal this in a second or two.)

From the above posts I get hint of 64 slaves per master.
Multipple masters are possible.
But how many channels per slave?
And what is the total max? Depending on system memory or what?
Probably a number that will fit in a ip subnet of 200+ device will be sufficient. Then again there may be multipple device ids behind an ip.
Anyone?

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PostPosted: Thu Jan 23, 2020 10:38 am 
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Ulvis wrote:
But how many channels per slave?


Max. 100 channels per slave

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PostPosted: Thu Jan 23, 2020 11:21 am 
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e.kislov wrote:
Ulvis wrote:
But how many channels per slave?


Max. 100 channels per slave


So... 64 slaves x 100 channels = 6.400 channels per Master ?

(1 channel ==1 read or 1 write telegram)

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PostPosted: Thu Jan 23, 2020 6:11 pm 
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Yes.

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