PROFIBUS Network Configuration

[AH987]

I am attempting to set up a PROFIBUS network to facilitate data transfer from two S7-300's to an OPC server on a PC. The communications modules I am using are CP5613 A2 [PC] & CP342-5 [PLC's].

I am confused as to the hardware configuration of the CP342-5, in particular the operating mode, i.e. No DP, Master, DP Slave.

I initially thought that the PROFIBUS network would be configured with the CP 5613 as DP Master and the two CP 342-5 modules as DP Slaves but I'm just not certain how to proceed. Any advice would be greatly appreciated.

 

[JesperMP]

For a "normal" OPC connection using S7 connections, you would not use DP master-slave, but master-master. This will also be the case if you want to use Send/Receive connections.

What is possible, will depend on the version of Simatic Net that you have purchased for the PC, if you have come so far.
If it is a "DP" version, the connection must be DP master-slave.
If it is a "S7" version, the connection must be DP master-master.

Just curious why you have gone the Profibus route.
I would have suggested ethernet.

 

[JesperMP]

The "S7" version is called "SIMATIC NET PB S7-5613".
The "DP" version is called "SIMATIC NET PB DP-5613"

 

[AH987]

The version of SIMATIC NET is S7-5613. I inherited this project after the equipment had been specified so had no input into the chosen solution.

 

[JesperMP]

I strongly recommend that you make the two PLCs, and the "PC Station" with the OPC Server, to be part of a single integrated STEP7 project.

You can find the guide I wrote in the downloads section about how to setup an OPC connection with Simatic Net. It is a bit old, and is about MPI, but it gives you a good starting point.
In the guide the CP5611 is used. You have to substitute that for a CP5613.

 

[AH987]

Thanks Jesper, that is excellent information. If you dont mind I have a couple of supplementary questions.

1. In SIMATIC NCM PC Config is there any significance in the assignment of an index value of 4 to the CP5611.
2. Can I assume that to include both PLC's in the project I just complete the OPC Server -> Insert -> New Connection procedure twice, inserting the PROFIBUS address of each of the CP342-5 modules when configuring the connection.
3. In address details I assume the slot value must match the CP342-5 position in the rack.
4. With regard to the hardware configuration of the CP342-5 modules, do I just select DP Master for both, assigning each a unique address and a transmission rate the same as that specified on the PC

Thanks,

Adrian

 

[JesperMP]

1. In SIMATIC NCM PC Config is there any significance in the assignment of an index value of 4 to the CP5611.

No. You can choose freely.

2. Can I assume that to include both PLC's in the project I just complete the OPC Server -> Insert -> New Connection procedure twice, inserting the PROFIBUS address of each of the CP342-5 modules when configuring the connection.

If you do like that, you must expand the dialog to ensure that you specify rack=0 and slot=2 to point to the CPU.
Alternatively you can "browse" for the CPU to make a fully specified connection.

3. In address details I assume the slot value must match the CP342-5 position in the rack.

No. The slot must allways be "2" for an S7-300 PLC. You point to the CPU as the target, not the CP.

4. With regard to the hardware configuration of the CP342-5 modules, do I just select DP Master for both, assigning each a unique address and a transmission rate the same as that specified on the PC

It is important that the CPs are "connected" to the same profibus network. They then automatically get the correct transmission rate, and importantly the TTR value is properly calculated by taking all partners into account.

 

[AH987]

Thanks Jesper,

I'll let you know how I get on.

Adrian

 

[AH987]

Hi Jesper,

I created a test project, to incorporate the PC station and the two PLCs as you suggested. I used your guide as a reference and substituted PROFIBUS where required. I stopped short of downloading the project to the CP5613A2 but up to that point everything seemed to go well. There were however a couple of things that I did not fully understand.

I initially set the operating mode of the CP5613A2 to DP Master with DP Mode the default DPV1. However when I later tried to save and compile the network the result was,

0 Errors 2 Warnings [one for each connection]

The details were as follows,

LocalID – The configured interface operating mode, combined with the set “DP” profile of PROFIBUS “PROFIBUS(1)” may affect the communication via the S7 communication.

Upon changing the operating mode of the CP5613A2 to the default “No DP”, save and compile returned

0 Errors 0 Warnings

Does this mean that in the parameter assignment of the CP342-5 modules the correct operating mode must also be “No DP”?

In addition to the above would you have any advice as to how I should approach the Send/Receive function configuration in the PLC.

I wish to make 8 words of data in the PLC [MB122 – MB129] available for the OPC server to poll

What would the typical function call configuration look like?

Finally, in "Address Details" I do not understand the significance of "Connection Resource"

Regards,

Adrian

 

[JesperMP]

Hi Adrian.

The warning message merely tells you that "DP" Bus profile is not optimal when the application for the CP5613 card is to connect an OPC server for S7 connections.
In stead of the "DP" bus profile, "Standard" bus profile is probably better, and will make the error message go away.
Not sure what selecting "no DP" for the CP5613 will actually do.

You dont have to use any send-receive blocks in the S7 CPU, or any other blocks for that matter. It is the OPC server that does the polling.

The connection resource is not relevant for you now.

 

[AH987]

Hi Jesper,

Ive set up the CP5613A2 in the PC and the installation seems to have gone well. I have encountered another problem while attempting to add the CP342-5 to the S7-300 PLC. I wonder if you have seen this one before. The details are as follows,

To add the CP342-5 to the PLC project I carried out the following steps,

· Established an online connection to the PLC.
· Uploaded the current program from the PLC to the PC.
· Powered down the PLC.
· Installed the CP342-5 on the backplane.
· Connected the CP342-5 to the 24vdc power supply.
· Powered up the PLC.
· Switched the CPU to STOP mode.
· Downloaded the updated hardware configuration to the PLC.
· Switched the CPU back to RUN mode.

At this point the PLC will not return to RUN mode, remaining in STOP mode with the FAULT LED illuminated.

The diagnostic buffer for the CPU indicates,

“Stop caused by parameter assignment error or impermissible difference between preset and actual configuration, start-up disabled”

The diagnostic buffer for the CP342-5 shows the module to be working correctly. The green RUN LED on the front of the module is illuminated.

If I download the original hardware configuration to the PLC the fault is cleared and the processor switches to RUN mode upon request.

The details of the CP342-5 are as follows,

Model: 6GK7 342-5DA02-0XE0
Hardware: Version 7
Firmware: Version 5.7.3

What do you think?

Regards,

Adrian

 

[JesperMP]

Download the updated HW Config again, then check the Hardware Diagnostics to see what the error is.

Post a screenshot of your HW Configuration.

 

[vuthanhbk01]

Hi Jesper,

I encounter the same problem as AH987.My application hardware configuration as below.

CPU314+AI+AI+AO+AO+DI+CP342-5( Firmware: V5.0)

Please get attached file and help me!
Thanks,
Vu

 

[JesperMP]

Hi vuthan.

"Parameter assignment error assigning parameters to modules (not on P bus, cancel download) "
I think this entry means it cannot "see" the CP342-5.
Is it powered up with a separate 24VDC ?
Is it linked with the "U"-connector to the backplane bus ?

 

[vuthanhbk01]

Hi Jesper,

1. CPU and CP342-5 are powered with the same power supply.
2. Yes, I have connected CP342-5 with previous module with "U"- connector.

Thanks,
Thanh Vu