Micro850 communication via Ethernet/IP

Hello,
I am trying to write a simple C++ application, which is supposed to be able to read/write data from and to an Allen Bradley Micro850 via Ethernet/IP .For this task I chose the Tuxeip library. I have managed to build the test examples, but now I encouter the error that the session can not be registered. In the debugger I found out that the Reply Header Command is an invalid value (which is 52685, also the length, protocol version and option flags of the encapsulation header have the same value. In comparison, the command value for registering the session should be 101). Does anyone have an idea where the problem could be? Is it possible that the tuxeip library is too old ( since the Micro850 is a relatively new PLC) ?

I would not try to use Ethernet/IP to talk to a Micro 850.
Setup the Modbus table in CCW for the items you wish to access and download it to the Micro. Then use Modbus TCP on the C++ side.

baldone said:

I would not try to use Ethernet/IP to talk to a Micro 850.
Setup the Modbus table in CCW for the items you wish to access and download it to the Micro. Then use Modbus TCP on the C++ side.

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hey, thanks for your reply. i am a student on an internship and we need ethernet/ip for the communication, we dont want serial communication. do you suggest modbus because it is easier to implement?

p.s.: a little update, i may have found the problem: its the MSG_WAITALL function which apparently doesnt work with windows sockets, i exchanged it with a simple 0 and the session can now be registered, which now leads to the next problem : i recieve now a timeout error when trying to read the PLC data..

igor_b1991 said:

hey, thanks for your reply. i am a student on an internship and we need ethernet/ip for the communication, we dont want serial communication. do you suggest modbus because it is easier to implement?

p.s.: a little update, i may have found the problem: its the MSG_WAITALL function which apparently doesnt work with windows sockets, i exchanged it with a simple 0 and the session can now be registered, which now leads to the next problem : i recieve now a timeout error when trying to read the PLC data..

Click to expand...

The Micro 800s are not the standard Logix 5000 implementation of Ethernet/IP. They are PLC_Open architecture based and I am not sure what can and can't be done message wise as far as Ethernet/IP goes.

They do handle MODBUS/TCP which is MODBUS carried over ethernet and is pretty widely supported.

baldone said:

The Micro 800s are not the standard Logix 5000 implementation of Ethernet/IP. They are PLC_Open architecture based and I am not sure what can and can't be done message wise as far as Ethernet/IP goes.

They do handle MODBUS/TCP which is MODBUS carried over ethernet and is pretty widely supported.

Click to expand...

Ignore...

I’ve not had the opportunity to work with the Micro850’s but there are two versions of EtherNet/IP, TCP and UDP. UDP is the most commonly used version in Logix based PAC because of its simplicity (among other things). TCP is what is used in SLC’s and MicroLogix. While a Logix PAC can use TCP the SLC’s and MicroLogix can’t use UDP. If I had to guess (and it is a guess) I’d say the Micro850 uses TCP or at very least can use both.

MicroLogix850 communications

Hello,

I have one guestion regarding MicroLogix850. Is it possible to use Modbas RTU and Ethernt IP communications at the same time?

The idea is to connect Servo with PLC via Modbas (plc will only be used to set reference) and the Ethernet will be used to connect some peripheral modules (I/O).

Thanks!