Task Description:
Currently I am working on a program in C # for reading data from RSLogix5000 Series controllers (v18.11). The idea is to do without the RSLinx OPC servers.
The program successfully works using the recommended mechanisms described in manual 1756-pm020 from Rockwell.
(https://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm020_-en-p.pdf)
Everything is fine, but with a large number of tags, the Update Rate greatly increases even using a Multiply Service Request.
I studied using Wireshark how the exchange between RSLinx and PLC occurs during the exchange of tag reading via OPC connection with the server and it can be seen that it is completely different.
You can see that RSLinx creates a class:
Class (0xb2) - Create
And then works with this class 0xb2 using the service 0x4C.
It can be seen that for one such request the controller sends all tag values in one package.
Question:
1. Can anyone help me how the communication mechanism between the PLC and RSLinx is built?
2. Is there any documentation on the classes of the RSLogix5000 series controllers?
Tried to search Google - found nothing ... I really need your help.
Thank you in advance.
Currently I am working on a program in C # for reading data from RSLogix5000 Series controllers (v18.11). The idea is to do without the RSLinx OPC servers.
The program successfully works using the recommended mechanisms described in manual 1756-pm020 from Rockwell.
(https://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm020_-en-p.pdf)
Everything is fine, but with a large number of tags, the Update Rate greatly increases even using a Multiply Service Request.
I studied using Wireshark how the exchange between RSLinx and PLC occurs during the exchange of tag reading via OPC connection with the server and it can be seen that it is completely different.
You can see that RSLinx creates a class:
Class (0xb2) - Create
And then works with this class 0xb2 using the service 0x4C.
It can be seen that for one such request the controller sends all tag values in one package.
Question:
1. Can anyone help me how the communication mechanism between the PLC and RSLinx is built?
2. Is there any documentation on the classes of the RSLogix5000 series controllers?
Tried to search Google - found nothing ... I really need your help.
Thank you in advance.