Hi,
I am working an a project with 8 Omron CS1G-CPU65 PLC's. Those are linked with controller-link. One PLC is equiped with an ethernetmodule and acts as gateway for the other PLC's. Each PLC has a cycletime of +- 70 ms.
The problem is now that if I want to read datawords from the PLC's from a SCADA on a PC, it takes a lot of time.
The communication between PC and PLC occurs via the Omron Fins Protocol. It uses UDP port 9600 to communicate with the PLC's.
What I found out is that a question from the PC is answerred after by the PLC 200 ms.
To check why it takes so long I've built a test setup with one PLC an a networkcard. After some test It looks like the delay between question and answer is caused by the cycle time.
So lets return to the project-setup (8 PLC's): If I want to question a PLC behind the gateway-PLC, I have to pass the gateway-PLC wich takes 70 ms, then ask the question to the PLC wich takes 70 ms, get the answer back wich takes 140 ms. This results in a total of 280 ms to receive ONE answer. Too long
Does someone knows a setting to use the ethernetmodule independend from the PLC cycle time (a kind of direct memory access)?
Any suggestion is welcome! Thanks a lot, WW
I am working an a project with 8 Omron CS1G-CPU65 PLC's. Those are linked with controller-link. One PLC is equiped with an ethernetmodule and acts as gateway for the other PLC's. Each PLC has a cycletime of +- 70 ms.
The problem is now that if I want to read datawords from the PLC's from a SCADA on a PC, it takes a lot of time.
The communication between PC and PLC occurs via the Omron Fins Protocol. It uses UDP port 9600 to communicate with the PLC's.
What I found out is that a question from the PC is answerred after by the PLC 200 ms.
To check why it takes so long I've built a test setup with one PLC an a networkcard. After some test It looks like the delay between question and answer is caused by the cycle time.
So lets return to the project-setup (8 PLC's): If I want to question a PLC behind the gateway-PLC, I have to pass the gateway-PLC wich takes 70 ms, then ask the question to the PLC wich takes 70 ms, get the answer back wich takes 140 ms. This results in a total of 280 ms to receive ONE answer. Too long
Does someone knows a setting to use the ethernetmodule independend from the PLC cycle time (a kind of direct memory access)?
Any suggestion is welcome! Thanks a lot, WW