Hello.

I have prepared the project based on ET1512 SP F-1 PN cpu with CM PTP (6ES7 137-6AA00-0BA0) wchich I had some bad problems when starting up.

The CPU is communicating 7 ATV320 inverters on modbus RTU.

Now it's time to extend the project with another 5 inverters.

As I had problems with starting up the basic project I have decided to extend the electrical panel by adding the IM 155-6 PN ST with 2 digital inputs , 2 digital outputs and another CP PTP (6ES7 137-6AA00-0BA0)

I have redid the program by simply coping the working project OB networks ( the working one ) and reduing it that the sequence of the calls for communication should work in pararel. 

There are two calls of MODBUS_COMM_LOAD using different instance DB's (DB60 and DB244)

For each call of MODBUS_COM_LOAD the software uses the proper hardware ID of the CM PTP (HW id: 260 for CM connected to the CPU, and HW id 377 for CM connected to IM 155-6 PN )

The MODBUS_MASTER are using different instances for each CM PTP calls.

The problem starts wen i try to start the seqence of calls for CM PTP connected to IM 155-6 PN.

On network number 1 ( CM connected to CPU i'm starting to get errors 80C8 on read operation and 818D on write operation.

On Network 2 ( CM connected to IM 155 ) I'm getting the same errors and sommetimes whole sequece finnishes with error 8200 interface buisy .

I'm getting little bit crazy . For each network ( CM card ) , the instances of MODBUS_COM_LOAD are different , when i checked the parameters inside the MODBUS_MASTER DB's the hardware ID's of the interfaces are different ant properly set.

The seqence of the modbus communication is called in OB31 .

Any ideas what could be the mistake ?

Is it possible for two CM PTP for ET200SP to work in pararell ? Or they have to work one by one ?

Ps. I did a checking if there are no two comunication requests same time on each network.

Cześć.

Thanks for reply.

For the test i have moved the whole sequence of communication from OB31 to the FB called in main OB1 .

As the CPU program cicle time is arout 60ms the only result is that whole communication cicle time on network 1 rised up from less than one second to around 2 seconds. I need to call the MODBUS_MASTER 14 times , 7 read registers operations , 7 write registers operations, to make sure that i have full control about calls I have wrote 14 calls of MODBUS_MASTER. Each call is triggered by done or error status of the previus call, so for each data exchange using OB1 at least 3 CPU cycles are needed.

The result is only extending the time, the errors are the same.

The wiring on the modbus network is independent, I undertand that there can't be two masters on modbus RTU network.

For the second network i don't care so much about communication cicle. If it will be neccesary i will play wit it later. First thing to make it working.

If anybody have some suggetions please help.

First CM PTP was working ok for last 9 moths.

After updating the project when the comminication of network 2 if off ( MODBUS_COMM_LOAD done ok but the communication is not triggered) I get nearly no errors on network 1, less than 0,1 % of the communication attepts finishes with error 80C8 - "The slave does not respond within the set time".

When i start the communication on the second CM PTP i starting to get the errors on Network 1

80C8 - "The slave does not respond within the set time" - on read registers.

818D - "The area addressed by DATA_PTR is longer than the DB, or the area addressed is too small for the number of data bytes to be read or written." - on writing the registers.

More than 1,5 percent of errors on network 1.

The network on CM PTP number two goes crazy. I get the errors :

80C8 - "The slave does not respond within the set time" - on read registers.

818D - "The area addressed by DATA_PTR is longer than the DB, or the area addressed is too small for the number of data bytes to be read or written." - on writing the registers.

8200 - The interface is busy with an ongoing request.

Hello.

Seems that the problem is somwhere elese.

The network 1 works fine with no errors, and when the network 2 starts it gives info about wrong data lenth and so one.

There are only ATV320 inverters in the system, so the data is exaclty the same.

I add an attachement with most important parts of the program.

I didnt added screens of all the triggers and all the MODBUS_MASTER calls , but the idea is the same , i did 5 times check of the double modbus master triggerring, i didn't found nothing.

If theres one condition which I have found and have no idea how to solve when MODBUS_MASTER instances are called the same time for different CM PTP the system goes crazy.

I'm trying to figure out why ;) .

Hello.

The only memory overlaps are for purpouse, the bits representing MODBUS_MASTER buisy status are overlaping the word from which i count if there are no double reqests of communication. If it happens , alarm bit is set.

The bool on function enable was used to restart the communication when the MODBUS_MASTER was freezing on buisy status. I's not used anymore. The bit was moved to data table "waists" wchich I usually remove after finnishing the tests of the software and clean all the uses.

Hello.

A little progress.

I have stopped the seqence of communication requests on network 1 (CM hardware id 260 in the CPU rack) and started the sequence for seconf network CM hw id 377 in the rack of IM155, for the first time i got the communication response on second modbus network.

After restarting the sequence for first modbus network i both networks are working but with a lot of errors:
8200, 80C8, 818D, new feautre ;) is the 81E7- which is not decribed oficially in the manual.

Hello.

Another test.

I have put both networks for both CM's in one sequence.

Now the networks works in this mode 

14requests for communication for network number one, when the sequence is finnished , the seqence for network number two is started.

The both networks work fine, but whole sequence takes more than 2 seconds, which is very long.

I'm trying to figure it out.

There are different instances for modbus com load for each CM, the modbus master are using different instance DB's.

And still when both networks work in pararel , the networks are going crazy, when requests are one by one, everything seems to be ok but the timming is awfull.

Hi

Have you found any solution for this?