IC695CPE310 writing to registers using modbus

Hi,

I have an Rx3i IC695CPE310 and I need to be to read/write to the cpu registers (4xxxx / %R) using modbus.

It look like the plc is set to a read only mode and I cant find any information if it is possible to set the plc to a writable mode.

I have set the option 'Modbus Address Space Mapping Type' to 'Standard Modbus Addressing' using Proficy Machine Edition. This enables me to read the plc registers just fine. How ever this option does not enable writing.


Could anyone let me know if this is possible to achieve on a CPE310 and which settings to enable?

Regards
Ryan

P.S. to give a bit more information on the specific application. I need to pull information from the plc into our bespoke web applications. I am currently using a library in java to pull memory value from older plcs in the facility. I am also testing the modbus read/write using a modbus master simulator called 'Radzio! Modbus Master Simulator'

If your Modbus device can read the %R registers but not write to them, it could be because you have assigned a security level to the program and the Modbus master can't enter a password.
I know of no other method to restrict access to read-only and certainly if such a setting existed it would not be the default setting. an HMI panel almost always requires read/write access.

Steve,

Thank you for the reply. I will try and find some references to security levels.

Also, just to curve the subject a bit. Do you have any advice on industry standards on how to access/modify data in the rx3i family of plcs using custom external applications. Specifically being able to achieve this through a programming language such as java.

Regards
Ryan

Also, just to curve the subject a bit. Do you have any advice on industry standards on how to access/modify data in the rx3i family of plcs using custom external applications. Specifically being able to achieve this through a programming language such as java.

Click to expand...

You would need to write a communications driver in one of the two protocols native to the CPU. That would GE's SNP protocol or Modbus. Or you could purchase a license for a commercially available driver from someone like Kepware and include it in your Java app.

Steve Bailey said:

You would need to write a communications driver in one of the two protocols native to the CPU. That would GE's SNP protocol or Modbus. Or you could purchase a license for a commercially available driver from someone like Kepware and include it in your Java app.

Click to expand...

Steve,

I downloaded kepware KepServerEx and pitched it to the higher ups. We will be using this software for all our plcs connectivity needs going forward. This is a great solution for our facility and its super easy.

Thank you for the recommendation.

Regards
Ryan