For an old s7 300 PLC Project, I am seeking advice on how to effectively manage alarms and trips using Modbus communication. Specifically, I am using the CP341 communication processor for Modbus communication.

Here are the details of my setup:

• PLC Model: Siemens S7-300
• Communication Processor:CP341

My goals are:

1. To configure the CP341 module to handle Modbus communication properly.
2. To set up the PLC program to send and receive alarm and trip signals via Modbus.

Questions:

1. Configuration:
   • What are the essential configuration settings for the CP341 to enable proper Modbus communication for alarms and trips?
   • Are there specific parameters or settings that I should be aware of in the CP341 configuration?
2. PLC Programming:
   • How can I structure my PLC program to handle alarm and trip signals via Modbus? Any examples or references to relevant programming blocks or routines would be greatly appreciated.
   • What are the best practices for integrating alarm and trip management with Modbus communication in this setup?
3. Troubleshooting:
   • What common issues should I be aware of when setting up alarms and trips over Modbus with the CP341?
   • Are there any recommended diagnostic tools or methods to ensure that the communication and signal handling are functioning correctly?

Thank you for your time and assistance.

Hello;

It is possible to use a CP 341 as a Modbus RTU master (it will then communicate with a Modbus slave, what equioment are youplnnng to send th alarm ata to?). But you will need to purchase a rather expensive license to do so.

https://mall.industry.siemens.com/mall/en/CA/Catalog/Product/?mlfb=6ES7870-1AA01-0YA0&SiepCountryCode=CA

You will find the manaul for this driver and how to manipulate the special blocks for Modbus RTU here:

https://support.industry.siemens.com/cs/ca/en/view/1220184

The S7-1200 and S7-1500  families of processors are more modern and integrate Modbus RTU  masterr and slave functions directly in the programming software (TIA Portal v1x) so it coud be much less expensive and a lot easier to implement your task.

Check out the software requirements for communications over Modbus RTU using the S7-300 and the CP 341 first. we can then discuss the collecton and transfer of alarms as a next step.

Hope this helps,

Daniel Chartier

Thank you for your time.

Could you help me find MODBUS RTU solutions with and without a dongle? What are the differences between them?

Do these solutions require a license?

This MODBUS communication is needed for an old project involving an S7-300 PLC to retrieve alarms.