Welcome to our new forum
All users of the legacy CODESYS Forums, please create a new account at account.codesys.com. But make sure to use the same E-Mail address as in the old Forum. Then your posts will be matched.
Close
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?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
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).
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
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.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
e.kislov hat geschrieben:
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?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
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?
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).
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?
Max. 100 channels per slave
So... 64 slaves x 100 channels = 6.400 channels per Master ?
(1 channel ==1 read or 1 write telegram)
Yes.